Probably no one will ever read this, but to drill glass like a champion you use slow speed very light feed, copper pipe, coolant, and abrasive! The copper pipe is soft enough to pick up the abrasive and carry it along the surface of the glass, scraping tiny glass particles away into the coolant. Using copper pipe sized to the diameter of the hole you want you will get a slightly enlarged hole, i.e. using 1/4 inch (.250) pipe could bore a hole .260 to .270 if you have a shoddy set up. This method will drill just about anything, so long as the abrasive powder you use will cut what your drilling. Diamond abrasive and copper pipe, plus time, equals a hole in anything thing you want. Coolant is a must and you really should use the coolant recommended for what your cutting. For glass, sea shells, and some stone, try dishwashing liquid in water (soapy water) mixed with the silicone carbide abrasive. If you want a perfect finish on the front and back, drill half way through each side and meet in the middle of the item. Drilling all the way through glass will almost always chip the edges when it breaks through. Placing the item your drilling on foam or a sponge will actually minimize the breakout and chipping of glass when you drill all the way through it. Wish anyone the best of luck trying this! If anyone reads this and it helps I would love to know someone got some use of my 15 minutes thinking about this response.
I believe you are the winner of the best solution. I was going to suggest copper pipe myself. Your reasoning seems scientifically sound to me, an old lab rat.
Before you attemt to "drill" mineral glass i advise you to check for internal tension in the glass. How? Take 2 polaroid lenses and orient the first horizontally and the second vertically with distance in between to bring your object after the first and before the second lens. Without glass object light transmission throug the 2 lenses wil be very dim. When you bring a hardened glass object in between you wil see tension "flames". With any flaming visible every attempt to drill or grind is useless. Kind regards from an old school optician.
Nothing constructive to add here, so I'm just going to read all the other comments. I'm anxious to see who's an expert cutting glass on a milling machine using a hole saw. 😁
***** If you can drill a small pilot hole though the glass without it breaking, you've at least a chance of drilling the large hole successfully. I think the Dollar stores have glass containers in similar shape and size; perhaps a cheaper glass might work better for this operation?
***** Well, you have found an expert here - Over my past three marriages, I have literally broken tons of these Pyrex dishes. Unfortunately I can't revel my trade secrets as I'm currently under a court order at the moment. So.. apologies, I officially do not have anything to add either.
I would have said something sooner but I was doubled over laughing. Your videos are gold. Fill the container with water. Thermal expansion is your enemy here. Maybe find an adhesive that takes heat well and glue the carbide to the hole saw. There's no need for wood cutting sized teeth for this so try cutting them down but leave some relief for slurry to exit.
tempered glass can not be cut. This dish was probably hardened for two reasons. makes it more resistant to damage from drops, and makes it more resistant to temperature changes. tempered glass basically has a large amount of exterior tension, and once released, it is explosive.
+Thomas Gunkler Yep, I work in a glass factory and one of the fun things we do to new guys working in cutting is give them a piece of tempered and tell them it needs to be cut down. The looks on their faces when the glass pops is priceless, especially if they know nothing about glass. Then ya gotta give them the old 'aw man that unit was hot... the boss is gonna be pissed' Good times.
+huhhman not sure about that. the issue would be the edge of the cut glass. tempered glass must have a tapered edge. if it has a sharp edge, it won't last long. so unless the laser cuts a tapered (beveled) edge. not gonna last long.
+Thomas Gunkler It can be cut, I saw a guy do it in another video. His technique though was to go very slow and dont use constant pressure like AvE is doing. I think it might be cracking due to vibration building up, you need to lift up the saw/drill. All the other guy used was water too I think, he didnt use carbide.
Journeymen glazier here. That's glass is heat strengthened. You can either anneal the glass again or buy a non heat strengthened dish to drill. Any glass that has gone through any strengthening or tempering process can not be cut or drilled with anything. An option you can try is to melt a hole in it.
Also the dish can not be tempered as tempered glass does not like heat. So it is heat strengthened to withstand higher temps. Same process. Just lower temps in the oven and shorter quench time.
there is a way to do it....you drop pyrex making it shatter into a million pieces...then glue the dish back together leaving out only the pieces where you need a hole. :) hope this helps.
Over all weight of the drilling piece should be minimal now you have heavy cuter heave chuck and weight of the turning shaft of the pulley all made a high impact on the glass to break . I think you can made initial cut how you cut and once you have a circular grove You can hold it against the cutting piece with you hand only so it absorbing all the vibration made Sure you ware glove.
How honest of you to show your results even when you're unsuccessful. It's quiet puzzling, why the glass breaks all over the place all of a sudden, even in places that seem to be totally isolated from the point you apply a force to.
That's a property of glass (and other structural plastics, like reenforced concrete) that has internal stresses caused by uneven or rapid hardening, often intentional. The desired effect is mainly to increase the strength and durability of the surface material, at the expense of the internal material's resilience. In short, once the internal stresses of the material become uneven due to a breach, it results in a chain reaction that pulls apart the rest of the structure, that approaches, sometimes exceeds, the speed of sound through the material. For pyrex glass, this is over 5000 m/s. A high speed camera filming at 25,000 fps would not capture two frames of the 8" dish fracturing, and 100,000 fps, only 3 or 4. To get better than 1 mm resolution of a fracture in progress in pyrex, would require a frame rate approaching 6 million FPS: a restricted technology.
***** Well. After reading over 200 positive comments on my German accent a few days ago, changing anything in that direction would simply be a "bad business decision", not even talking about "staying true to oneself" and that kind of stuff. BTW: I had to smile when I heard you talkin' French all of a sudden. Must have caused some irritation :D
Nevin Williams That is why you are not supposed to bang a hammer directly with another hammer. They can "explode". "Crystals" have this tendency to get stressed if they are cooled too rapidly and snap, releasing this energy, if you push them beyond their maximum tolerance. Meaning they are not "plastic" in behavior at all. I do not think that concrete forms crystals. Granite on the other hand will blow out if you heat it or hammer drill it.
AvE; You got it when you referenced the Prince Rupert's drops. Pyrex is pre-stressed glass and that is why it is rock hard and tough to break. You are cutting through the outer stressed layer, stress now looking for places to go, and shazamm you have broken glass. I know in lab class, the only way we could ever try to do anything with Pyrex was to heat that stuff up until it was just about molten and then try to manipulate it. And try to manipulate it is the key phrase. The techs in the shop who made glassware for the profs and grad students would laugh their asses off watching us undergrads try to make something. Well worth the experiment. Regards; Ron Kluwe
Modern pyrex cookware is stressed soda glass, pyrex lab glass is borosilicate. Higher temps used to work borosilicate than "standard" glass but in itself it tends to be more durable.
Nobody seems to be explaining why tempered glass is hard to cut so I'll try my best. I'm sure someone else can do a better job. When a substance like glass is heated it expands and when cooled it contracts. When it is cooled rapidly (i.e. tempered), the outer layer contracts rapidly and its tension places a constant compressive force to the inner glass. When the outer layer is damaged enough to fail, it releases all that compression simultaneously causing catastrophic failure to the piece. I don't think it matters whether the damage is caused slowly or quickly, only that it exceeds the tension balancing that compression force. Prince Rupert drops are an example of what happens when that force is released. It's not the specific location of the damage on them that causes them to explode, but they are under such extreme compression which makes them so hard that you can only cause the damage the tail with conventional tools. Unlike steel, I have no idea if/how tempered glass can be annealed (removing just enough of the temper to relieve the internal stress) but it would seem to be pointless in this case because the goal is to end up with tempered glass at the end. Gorilla glass achieves some of the same surface strength results through a chemical process rather than a heat process, so it might be possible to do this kind of work on a gorilla glass piece if they ever make cookware out of it.
Andrew Crews And this is special how? You can bend the microscope cover plates too, which i believe is thin untempered glass. Resistive touchscreens fully worked based on glass surface bending, and they were not made out of Gorilla glass, they were made out of... not sure, untempered glass? Thermally tempered? I don't know, it was bonded to a plastic sheet usually and hard to break, but eventually they did break. Glass fiber is VERY bendy. Thin glass bends.
+Tim Gilbert Actually, when molten glass is chilled quickly, the outside freezes while the inside is still hot. Then, as the inside cools, it contracts and puts the surface under compression (the inside is under tension). This surface compression closes micro-cracks which are the source of all weakness in materials. A great book about this is _The New Science of Strong Materials or Why You Don't Fall through the Floor_ by J. E. Gordon. This also explains why it breaks just before the hole is complete. The inner bulk strain is relieved, so the surface compression goes away, and the glass cracks.
+Chris Uhlik They use the same process for new cast car rims. Cool the outside and keep center hot when casting makes the wheels stronger by having forces under tension.
Glass artist here. If you can't be arsed to buy a glass bit, you need to go slow, use a softer material for the bit, (wood, maybe?) and put as much water in as you can get to help prevent thermal shock. It's also a good idea to back off every now and then to let more grit get into the groove and rinse the glass powder out.
Cool, but say he goes with the softer material, because shits and giggles, wouldn't that increase the surface area and make it harder to cut? Is it pretty much a case of "suck it up buttercup, she gonna take her time"?
The only concern with surface area is how much glass you're wasting. The "bit" isn't doing the work, it's all about the abrasive. You don't cut glass, you slowly sand it away or break it along an induced fault.
Dominic has sound advice. My diamond saw runs on nylon wheels. The glass get hot even with water and glass is no forgiving. Slow is key. Sanding the glass down.
The same technique is used to cut holes in telescope mirrors. However, you use a copper tube in place of your hole saw as the carbide will embed into the copper. If your glass dish is tempered, it is pre-stressed and will shatter if the surface is scratched or damaged. Look at it with polarized sunglasses, if it looks splotchy, it is tempered. Find one that isn't. Older ones weren't.
This is tempered (or toughened) glass, which has internal stresses which increases its resistance to fracture. Cheap tempered glass (usually cooled too quickly or at a wrong temperature) generally has uneven stresses throughout and can even spontaneously fracture (e.g., like some cheap Chinese glass patio furniture). This also means that if you relieve some of the internal stresses, they tend to fracture readily.
2 things. No. 1: yes it hurts for no reason, time for special old persons exercises every morning, shoulders and neck are the worst, where you retain the most tension. No. 2, don't know what the temperature of the glass was, cold glass cuts badly. I assume the water transmits heat away from the cutter so there is a minimal heat gradient across the whole dish, but it is almost as if the bottom has expanded so put the sides under tension. Cheers, Andy
Hi, I really enjoy your videos and your comments are a blast. I KNOW what the problem is because I have solved the exact same problem. BTW, I am a Ceramic Engineer (I bet you didn't even know they existed...). To start, Pyrex is an annealed glass, not hardened, intentionally to reduce internal stresses. What you are running into is due to intense ultrasonic vibration. This is revealed through the break pattern. If it was due to glass tempering, the piece would have shattered into many, many pieces. If it was due to local heating, you would see the crack propogating outward from the bore hole. These cracks originated at the outer edge and propogated inward. The starting points are also spaced out about 12cm apart around the top edge. All of this points to ultrasonic vibrations. The vibrations are caused by the grit rolling and skipping around at the blade/glass interface. There are a couple ways to address this. You were on the right track trying to embedd the piece to reduce motion. If you had embedded the edge of the bowl, it may have worked. Ultrasonic vibrations scatter in weird patterns and are hard to predict so even this approach is no guarantee. Another thing to do is replace the metal blade with something like a hard rubber or maybe a fiberglass impregnated plastic. And of course another thing is to go with a cutter that has the grit embedded to you don't get all that rolling and chattering around, which is what you were trying to work around in the first place. Even then, it is a good idea to dampen the edges. Good luck.
Works great on glass plates! I suspect that it's VERY difficult to drill cheap tempered glass. That stuff is like car side-windows: you can hit it with a hammer without damage, but any major scratch causes the entire thing to fracture explosively. So, your smooth SiC damage must not be causing problems, but something like a tiny fracture or deep scratch can set off the explosive disruption. The physicists hole-saw is a copper tube. With the soft copper, the SiC becomes embedded in the rotating edge, so it turns into a DIY diamond saw. I don't know if steel does this at all. Probably aluminum pipe does it too, but copper tube of desired diameter is easier to find. Get your lathe and whack out a precision drill from scrap aluminum rod? And I think a thinner slot drills faster, but I haven't tried that. Easier to apply large force using small weights. Or this: perhaps try DIY pre-annealing, bake the glass at ?800F? or hotter? Get it up almost to softening temp, just below dull-red glow, then turn off the oven and let it cool over hours. That would un-temper the bakeware glass and remove the shattering effect ...but also make it far more prone to fracture if later dropped or heated (don't use un-tempered drilled glass for baking or cooktop!) Or maybe its possible to find actual cheap crap glassware, non-pyrex non tempered. Find stuff that will shatter if used for baking. Without the gigantic internal tension produced by annealing, it will act like thick window glass, rather than exploding like Prince Rupert's drops. Total garbage glass can be drilled, and expensive borosilicate chem-lab glass can be drilled. It's the in-between stuff, the tempered soda lime glass that's the problem.
wbeaty what about a cerium oxide paste? also it sounds like the drill bit is striking the glass. maybe make a plywood base on the end of a shaft that just grinds the glass out?
wbeaty Tempered glass is like a flat Prince Rupert Drop. One can surmise that the only way to drill holes in it is to anneal it in a big oven then drill it when its gone cold. The re-tempering is allegedly done by re-heating it then blowing cold air on it.
Hey for that neck you're going to want to look up a video here on youtube. Search beginners yoga. The one that shows up from the Yoga Vidya channel is the one to do. Do it for a week. It'll set ya straight for a good chunk of the year. I'm getting old too. Turning 22 in December
Yep, getting old means that you hurt every damn day (and night) Voice of 70 years of experience. I would make a "saw" from aluminum tubing, cut a slot in two sides. The breaking may have been high frequency vibrations. Every time it freezes my stick sticks to the ice!
If I remember right, Pyrex is under constant pressure, which is how it works. Something about having just the right amount of stress making it near unbreakable. I imagine that when you cut into it, it's breaking that tension as soon as you cut too deep, and snap, crackle, pop! I'd suggest using a non-Pyrex glass and see if you don't get better results.
I remember reading about this phenomenon. Tempered glass is stressed and once you get to the chewey bit in the center it wants to relieve it's stressed outer part, so as the saw makes it to the sweet spot it gets all kinds of wonky and the the outer stress is no longer the same and it says "screw this" and finishes contracting, and then the glass shatters. Work around - HEAT UP THE GLASS =)
Baaaa ha ha ha! That jump cut editing was hilarious! Thanks for the laugh. A bright spot on an otherwise blizzardy snow shovelling filled Ontario day. Cheers
The "new pyrex" el cheapo stuff is just tempered glass. Once you start cutting into it and releasing some of the stress, it's like a row of dominoes. You're going to need real pyrex ie borosilicate or just good ole soda-lime glass. Borosilicate will take longer to cut through but comes with it's benefits. You could also remove the temper on the glass, but it's a whole lot less work just to get soda lime unless you need the properties of borosilicate.
Grind the teeth off the hole cutter, and just use a flat face? Use a softer metal on the hole cutter? Some thick copper or mild steel pipe? The silicon carbide might imbed itself in the metal and make a nice grinding surface. Heat the glass when you are part way though, and let it lose some of its temper? Maybe that will ruin it for the purpose you want. Flush out the glass dust and put fresh grinding compound in? Reduce vibration by using the end of a pipe that has been rounded off a bit? Reduce vibration by using the end of a pipe and filling the interior of the pipe with something to dampen the vibration? Plasticine? A rubber or plastic plug that has be pushed in far enough to clear the thickness of the glass?
Maybe try annealing the vessel before you cut it? Annealing for glass should be ~550C but there's a whole cycle of temperatures and times to make sure the glass is heated and cooled in a controlled manner. Do you still have the kiln or did you never get the bronze lining out of it? :)
From my humble amateur glass blowing experience, I would second Smidge on that anneal. > 514 deg. C for sodalime (standard glass) > 565 deg. C for borosilicate (pyrex and imitations) . With a kiln I would heat the container to temperature. Leave it a good 30minutes for the heat to chooch in there and let it cool down slowly. Of course there is also the real man's way to do it with a torch. I would start by heating the container with a "soft flame" (basically a flame with no or few oxygen that looks more like a lighter on steroids than a torch flame). trying to heat the thing as equally as possible. At first it's going to let soot on the glass, That's going to disappear as you get hotter (and start to let more oxygen in. To know when to stop heating, one could use a thermal camera, if it goes there. I would simply close the lights and and heat until the flame become street light orange (from the sodium burning or something). If you to see the glass glowing red when the flame is removed, that actually might be too late for a sodalime glass (melted), but that would make a great video anyways) . Let cool between a bunch of heat resistant covers or hot sand or in the barbecue, whatever. Once cold, As said by many others, I would try using an aluminum or copper tube à a milling form. instead of an hard piece of metal. A softer metal will be more "compliant" if something hooks between the glass and the cutter. As you did, leave plenty of water for coolling in there. The gluing might actually be great for vibration damping and to hold the pieces and grinding juices from t'chouching on the lathe once done. Maybe lifting the bit frequently to make sure that the SiC grit get under the cutter and that I am not simply grinding glass with only the glass flour stucked under the cutter (SiC cuting glass = Sick fast, Glass cutting glass = Gloomy fast) Good luck! (And if you append to reach the point where the sodalime starts melting ... keep heating the spot that you want to remove and stick a piece of steel tubing or wet wood in there to make your hole.)
I haven't read all the comments nor do I think that AvE is going to read this. A while back drilled out a few holes in single pane windows for AC vents. I used a similar fashion with a drill press and bi metal bits in reverse. I found that it works if you score the glass with a circle cutter and score a grid in the id of the circle you are cutting out.
can you heat treat the glass to de stress it? i have no experience other than my housemate and i tried cutting a safety glass plane about 1.5x2m needless to say... there was blood and a lot of mess
Use a smooth tube as the cutter, the teeth of the bi-metal saw are generating vibrations that work on the glass. A copper tube ought to work fine, as the carbide is the actual cutting tool here. Secondly, due to the heat treat of the glass, internal stress is high, so use a bit of clay around the edges of the glass to dampen vibration. Third, build a small (say 4" diameter) clay ring around the hole area and fill with the water and silicon slurry to localize the cutting mix. put water outside the clay ring to aid in vibration dampening.
Thiago Ennes Water jet shatters tempered just the same as anything else. As soon as you compromise the outer layer, the internal stress causes it to fracture. The only thing that partially made it through was a laser before on colored tempered glass mostly because the laser, by melting the glass, would relieve some of the internal stress, but it the end, it shattered just the same. The only way to cut tempered is to untemper it.
***** That has been my experience as well. One of my hair-brained projects required a tempered glass tray, and after 6 attempts using similar methods to what AvE tried, we brought 3 more trays to the water jet shop, who warned us that the outcome wasn't likely to be successful. Only one of the three trays ended up with a clean hole without shattering, and it seemed like it would have done the job, but when it warmed up in the car on the way home, it spontaneously shattered as well. We ended up using a stainless tray with a tempered glass window.
I am so happy I can give you an answer! Pyrex is tempered glass. Tempered glass is unique in that you can take a mallet to the broad surface of tempered glass and there's a good chance that hammer will bounce off and hit you instead. However, a moderately light amount of force either from the edge of the glass will cause it to shatter or, if a sharper fragment than glass is pushed into the surface (I saw a guy on a video shatter a piece of tempered glass by hurling a piece of ceramic from a spark plug at the surface). Standard practice of cutting glass is to use either annealed or laminate glass. First you cut them very similarly to your idea except a reservoir is made for lubricant from glazier's putty and gasoline (don't use gasoline. that's what the old timers used -C2H6O is fine). TLDR; Glass is cut before it is tempered.
+AvE Will diamond hole saws go through it? Ive drilled some pretty hard brittle porcelain that had the double fired surface tension thing going for it with em. I have a set
Hey Brother, The only thing I know about glass is that it breaks easy and cuts you really bad but, I can tell you from many years of experience that every thing you did to your body in life comes back with a vengeance and it seems to just happen overnight! Get used to it because it gets worse as time goes on! Ray
I agree with the comments below about the pre stressed layer, this is probably a task that is really hard to do with Pyrex, cheaper quality dish may actually be better, but thats a guess. Also drilling the hole closer to the center, and away from the stress concentrating curved sides may help. I did have an idea if you wanted to reduce vibration, you could secure the pyrex into a larger tub, and the put fluid around it (additional fluid in it is obviously gonna get in the way), to dampen vibration, possibly reduce possibility if sonic fracture. But that might be a solution to a problem that isnt present/the most pertinent.
Don't clamp it, at most use some silicone. Cut the teeth of the saw off so it is just a tube that might also help, a soft tube would be better as it will load with the abrasive. Reduce the down pressure, grinding can be a very gentle process. But maybe the internal stresses are the issue and you just can't do it without some sort of annealing.
So glad I came across this video. We got a new "Pyrex" measuring cup because the paint on the old one wore off. A new one was cheap enough so we got a new one. I was going to clean up the old one and etch it so the writing would never wear off. I wondered why these things were painted instead of etched. I cussed the manufactures for being cheap and building in planned obsolesence. Before I etched the glass I answered my own question by remembering that the good old Pyrex was made from borosilicate while new Pyrex is made from tempered soda lime. Suspecting that etching would weaken the glass I decided not to etch the old measuring cup and just buy a new one every 10 years. This video and following discussion confirmed my suspicions. Real diamond bits are dirt cheap these days BTW but that wouldn't have helped anything. It was the internal stress not the drilling method that caused the failure.
So after a little research to whats going on with your fancy bake ware here is that pyrex is now made using tempered glass, now that being said what is causing the point of failure for the hole. Well to get into that tempered glass is basically a form of stressed glass. so when your cutting your hole here every time you getting through or close to the center of the glass you giving the glass enough "weakness" (someone could of said that better). to shatter under is own internal forces. Now the fix buy cheaper glass or more expensive glass that are not under the internal forces that are found in you tempered glass ware.
I wanted a hole in some tempered glass cookware too. After failing a few times with the same results (didn't use silicon carbide powder), I asked a friend to help out. He just set it on a hot plate and drilled right through. The temperature does not have to be hot enough to melt the glass, just hot enough to relieve the tension. It cuts a bit faster, even though the Chuck was turning a LOT slower than I would have thought necessary.
Yep obviously defective glass. Great video though. I hope you picked those up at the store and not in the kitchen, just saying. I get the same level of success cutting holes in glass with a 45 acp but it is a lot faster. Thanks for the video.
I've had great luck drilling or trepanning holes in glass etc using a similar method. Yes, SiC abrasive and water BUT instead of bimetal hole saw, I use copper tube or pipe. Dead soft annealed with some tri file fornication to get the abrasive to the cut. My wife likes to make desert serving tiered plates, each with a 10mm hole drilled. I do the drilling and have yet to crack or break one. Pine pitch makes great backing, melt it and bed the item to be drilled to cast iron platten etc. Keep it cool with some solid tap water if the shop is warm.
If it's the new, cheap 'Pyrex', it isn't even Pyrex (Borosilicate) - it's just tempered glass. Corning sold the Pyrex trademark to a Chinese holding company, and now they're selling bogus product.
Yup getting old sucks that's for sure. As for putting a hole in glass try using a torch and slowly heating up the spot that you want the hole in. Or you can put an old socket in your glass pan then heat it up with the torch slowly until the socket melts a hole in the diameter you need..
I just recently thought about it but i believe you can use hydrofluoric acid to create a very clean cut without releasing the stresses in the glass and such and shattering.
I would recommend that you use the softest metal cutter that you have, but use, basically, a goop of the silicon carbide. Basically make a think paste of the stuff. and stuff it inside of the bit. As it goes down, it will deposit the mixture onto the cutting surface and will cut the glass with more ease. make sure that you also put some of the mixture on the outside of the bit as well so that you cover everything so that it will be the most effective as an abrasive. ALSO, from what I have seen with glass, you have to either go really really fast, or really really slow, never take the middle ground. when going fast, just remember that you don't want to hit the resonant frequency of the glass or else it will shatter without warning. Like you said, this glass is under stress, most likely caused by the tempering that factories do, because of this, I usually go on the slow path. Hope this helps, -UnforeseenLife
Did both drill attempts fail at roughly the same drilling depth? Is the hole saw bit tapered or flared inside to where at a certain drilling depth it grabs onto the glass cookie it's cutting out, jamming and causing failure? I think the baked in tension of Pyrex could be a cause too, but wouldn't it break sooner if it was? Wouldn't a glass blower burn a hole with a torch? You could try that, or a cheap glass bit hole to prove or disprove the tension theory. Slow speeds and a light torque setting could help? In my experience using a hole saw, it wants to rip the cookie out at the end, you could try drilling the bottom to form a deep score, then drill from the top. Put some abrasive inside the hole saw. Idk just ideas. Love your channel.
Your intuition is correct. New Pyrex from the past several years is no longer borosilicate, but tempered soda lime glass. They made the change in the U.S. to thwart people manufacturing drugs, can't recall which one unfortunately. The drug making process relied on the low CTE of the BSG to crash cool something, the soda lime can't handle it and will shatter.
I'm going to go with sonic fracture here, the teeth on that hole saw probably cause a vibration at the dish's resonant frequency as they bounce along the surface, maybe try a softer cutting surface with no teeth and lower speed, as others have suggested.
It's only because it is crap that you got as far as you did. Think of tempered glass as being like a balloon. As soon as you put a hole through it, no matter how carefully, BANG.
I used to cut holes in the bottom of whiskey bottles for a carnival ride effect in a similar way. I made a dam around the hole with clay and chucked up a 3/4 inch copper sweat fitting in the drill press. It always worked.
I like what you tried to do. Reminds me of critical flaw size fracture in reverse - when the uncut section equals some critical dimension the thin section pops and propagates. I have seen glass cut all sorts of ways with a water jet. Garnet + H20 at 50kpsi. Some smart guys morphed that technology into Garnet + liquid NH3 at 50Kpsi to cut up something special for a undisclosed client. It ended with tears and a call to the fire dept, but hey we have to push the envelop. Google patent 6080907 for the public domain version.. A Sears pressure washer should be able to do 3000 psi maybe that could work just more slowly than the 50kpsi slicer of doom.
That is freaking cool. My dad worked in the high precision optical instrument industry, and used to come up with some pretty cool stories of stuff hiding behind closed doors.
I have drilled through quart fruit jars with the silicon carbide slurry and a piece of copper tubing as a bit. The drilling action is very slow and use a pecking action on the feed. This limits the heat and allows fresh abrasive to flow into the cut zone. The soft copper doesn't bind in the cut. I use modelling clay as a dam around the work area to contain the water slurry. It's slow but it works.
Pyrex needs to be stress relieved. Gotta use something else that's not oven-safe. Also, have seen cheap hole-saws at our (aus) big-box hardware stores for cutting thru tiles to fit over taps in showers, etc. might be the solution instead of toothed holesaw or diamond-tipped thing. They seemed to be a tube with abrasive stone glued on one end.
Being Pyrex I would be surprised if you could achieve what your trying, and if you did I would expect it to end up being a hair trigger from breaking soon after. Pyrex is just to highly wound up with stress. Does it have to be glass? I think you would have much better success if you attempted what you are going with a ceramic baking dish. It would likely survive subsequent handling and temperature variations a lot better than glass. You might be better off with a softer metal cutter as well. The old style cutters before cheap industrial diamonds use to use brass and sometimes copper, no teeth at all. (except maybe for a slurry slit). The abrasive slurry embeds particles in the relatively soft metal edge. (maybe use either very thin brass pipe or maybe a large copper pipe off cut). Also the resonance frequencies maybe a bit more dulled than with a hardened ferrous cutter so the rest of the work piece is not being punished as much. I have also heard tell that sometimes they used slurry with almost razor thin Stainless steel shells. I think the principle was that the abrasive worked on both the sides of the cut but also wore the SS shell leading edge to an ultra thin ragged (microscope level almost) cutting edge.
Hey I'm a glass blower and i think the problem might be heat stress from the bit. I also work in a machine shop and know that end mills create a lot of heat especially with constant friction. It appears that the break occurs at around the same point of the cut and it could be that enough heat accumulates and causes a heat fracture causing the glass to fail. When i drill holes with an abrasive drill I usually back off to expend heat and clear the glass dust (chips) that are left behind. If it was tempered the vessel should have shattered as soon as the cut started.
No, +Connieandblyde -- that is what was done at the factory, which is the cause of failure when the hole is almost through. The glass needs to be heated as hot as his oven will go, kept there a few hours to let the glass "relax". Then very gradually turn the temperature down, over the course of a whole day. At the end, the glass will have near zero internal stress, so it will not be prone to cracking.
harmonics is a good suggestion of the cause. You could hear the squeeking. The vibrations got to bad. Possible the suggestion using a copper pipe as drill-bit would dampen the squeeking?
I've drilled holes in glass but a little differently. I used 1" copper tubing as the cutter. I used some Clover lapping compound. I just smeared a bunch on the end, ran it at about 300 RPM and gently pecked at it. Let the grit do its work. I drilled into some beer and wine bottles. CLC is just silicon carbide and grease.
If this was a Prince Rupert's Drop issue (inside under pressure, but unable to defeat the outside surface tension), it would rupture and explode the moment the surface of the glass was broken, and the entire dish would likely disintegrate.
I work with tile and the diamond blades cut trough the glass no problem, I usually do it on the water saw. Your best bet is to get the same hole cutter like in the vid but naturally with the carbide tip for cutting porcelain, B&D makes nice ones that I have used before to drill trough hard full body porcelain. I would also recommend to put 3-4 layers of blue tape on the glass where u want to open the hole and fill up the glass pot with water.
+Kevin Jacobson yeah. im with this guy. though i think a kiln is over kill. you could probably put your oven on self cleaning with the dish inside and walk away. i've done a little bottle cutting and its some finicky stuff, glass.
+Shadowrcmegatech yeah! I watched a lot of videos before I started doing it and I found his to be the most informative. although he tells a few fibbs in his video "that would only take like 5 min to sand smooth." no. I don't know what he calls smooth... or 5 min but that's BS. second all I use is a micro torch. no water or ice. plus I use wide painters tape to keep the HAZ (heat affected zone) down to a minimum. I'm about to start experimenting with annealing or normalizing the stresses in the glass first before I cut. got a lot of broken wine bottles at the house. Which brings me to another fibb. the best bottles are easier. subscribe to my channle and I promise to post a bottle cutting video soon. you can seey set up, tools and method. might even break a few bottles too :D
hexadecimil holy shit! Is the painter's tape a common thing? I tried putting painter's tape .5in above and below the scoreline cause I thought it would help. I think it does at least a little bit. Where do you put painter's tape? Yea it definitely takes awhile to sand the bottles. I put wet sandpaper on a foam floor mat and keep the cut bottles in the same place as I rotate them back and forth. How close to perfect can you get the bottles using the torch? What % are successful? How often can you save both halves? For me it really depends on the bottle. Glass soda bottles are the easiest; sometimes a perfect scoreline can end up forming a crack most of the way around without any heating or cooling.
+Shadowrcmegatech yeah. it really does depend on the glass and apparently Coca Cola co. uses the best glass. wine bottles on the other hand are a real crap shoot. so far I'm 1 and 3 with those. beer bottles are the all arround best. though they break about half the time, they are plenty full and easy to score because of the often straight sides. as for the painters tape I go about 1/4" below the line, which Google tells me is round about 6 mm (just in case your not state side) I do this to further isolate the HAZ as much as possible to the score line. since I don't care about the top of the bottle for making cups and vases I hesitate to say I've saved every one, even the ones where the bottle broke on me. I've got a stack of them. maybe I broke one. not sure. now I haven't experimented with quote, unquote annealing the bottle yet but I know that glass will melt round about 2000°F so I'm dubious 360°F in my toaster oven will do anything but I'm gonna try it anyway.
heat up the glass and the water? and keep it all warm constantly? ive made a bong from labware before but also i went to the home store and got a glass bit. and used a propane torch to keep it all nice a cozy warm. took a few beakers (9) but i did it. thank you to my old high school for the "donations"! ha!
I have drilled through glass using a copper pipe as a tool, Silicon Carbide as abrasive but you have to be patient and use a pecking action with the quill feed so you are grinding for maybe 1-2 seconds, lift the tool and let the abrasive replenish then go anoth4er 1-2 seconds. This helps cooling and keeps fresh abrasive in the cut.
steamgadget has it right about drilling. However, whenever I need a hole through glass I use my abrasive blaster w/200 mesh silicon carbide. Use a rubber or plastic washer as a template. Takes under a minute to penetrate 1/4" plate glass. I think you're right about the pre-stressing. Likely a result of improper annealing.
I've cut thru tempered/saftey glass by scouring the area to be drilled first, then going at it. Whenever I have clamped what I wás drilling it broke, I use fabric as a buffer between my clamp and material. It keeps the vibes down. cheap bits do best on glass.
Stupid question maybe but does your glass container with the hole in it need to be Pyrex? If your not heating it after I'm thinking of an aquarium type setup. Old window glass cut with glass cutter and make your own vessel by the same means, silicone the corners. Easy to drill that type of glass.
It's tempered glass. Made to resist impact. You'll want to slow the drill way down and keep the silicon carbide slurry flowing to the saw in a constant fashion and keep it cool. A hot spot causes the glass to expand and kaflooey. Lots more slurry might do the trick if you keep it chilled and mix it during the process.
I got about three uses out of a 30mm diamond bit drilling through the bottom of very chunky whisky bottles. Made a dam out of bluetac and filled it up with water and added more when it started to heat up. Very slow feed and very light pressure toward the end. Even then, I got a small chip when breaking through each time.
- Don't use metal, use something much softer, like a pvc-pipe (maybe copper or bronze will also work). With a hard material like steel, you will put the pressure on only a few points. The softer material will also hold the abrasive in place - Glue the glass on a hard surface. I used thin spread hot glue on a steel plate. - use oil as lubricant. Water is OK, but oil worked better for me. And only make a paste. You have to reapply it regularly. - Reduce the pressure even more when you nearly through. Glass breaks from the surface, the smallest crack will travel trough the hole object. I hope it helps.
I once tried to cut a hardened table glass on a water jet machine. It was a security glass, the one that brakes in thousand peaces if you brake it. In the beginning we cut with very low cutting speed and it cut fine. But as soon as we increased cutting speed it broke. So from my experience of that project, what you could do is to try again with minimal force. The stress in glass should not be underestimated. If you heat a glass bottle with a welding torch it will beak.
Pyrex sold in North America is no longer made of borosilicate (as AVE kind of noted). It is tempered (pre-stressed) soda lime glass and can not be cut without being annealed first. Can't be done, as soon as you remove the stress from the one side (in the cut) the stress from the other side will break the glass. This will work fine on an old Pyrex dish made of boro, or some kind of untempered, not-for-cooking dish. Stock up on old 'real' pyrex at flea markets and such when you see some.
I have used a cheap diamond coated hole saw from a good hardware store to cut holes in normal liquor bottle glass. The key is very low pressure and a slow but steady water supply to keep the heat down.
A few years ago I built a decently large Dobsonian Telescope 12.5" and I made it out of a big thick glass table top. First I used a hammer to bust it into smaller pieces because it was like 36X36 and 0.75 thick. Then I got some of those diamond dremel like cutting wheels from Harbor Frieght and used those to cut little pie shapes out of a rotozip diamond blade. Yeah I tried a normal cutting/ grinding wheel and that's a no go on diamond =). With a few of those pieces I attached them to the ends of a fly cutter so they were 12.5" apart. I used water and just let it go. I actually have a really short video of it on my phone somewhere. I also used a super calibrated auto feed system like you but I think mine might of been a gallon jug with water in it ;).
29.10.2015 Hi from Switzerland (the country next to Hilti-Land and with the nice money) What about: 1. cut the big glass to small parts, one has to fit to your needs 2. fix it very very softly with clamps as if you would clamp your little finger ;-) 3. avoid or fix the sharp edges of the glass - do they have any tension left? 4. heat the fixed glass a little bit with a heat gun (no direct fire please) - if you use water - no cold water, rises the tension, use warm water to egalise the heat between glass bottom and the drilling circle 5. drill it, stop from time to time, heat it gently to egalise the heat between glass bottom and the drilling circle 6. start drilling, watch for cracks in the glass 7. if I'm wrong with this tip... do you best to "compliment" me in your unique way 8. try plan b: put a fitting small piece of glass in the lathe and do as the young Dr. Frankenstein: try it to drill - may be from the inside to the outside? 9. Important: this advice is given freely and if you follow it fully or partially - it's on your own risk and safety - you are a Canadian so you have to have a brain and take a good use of it (xxx sticks paperclip in ele...) so no fat chance to see me in the front of a jugde or court...
I used to fret over that "I can't do as much as I could when I was younger" thing. When I was 21 y/o, I could to 135 pushups. Now I'm 62. I pay people to do pushups for me. Thanks - Lumpy
Might be good to put it in a kiln at 1200f and leave it for 2 hours then shut the kiln off and let cool naturally, this will get the pyrex hot enough to flow without losing shape and will remove the stress that is trapped.
Alrighty boss I haven't had the need to try it out on Pyrex or tempered glass. But it does work and quite well on regular glass. I learned this trick making bongs out of Miller High Life bottles. Tape yes that strip of plastiqu with the sticm on the back. And for that dude I recommend heavy duty packing tape. Maybe even the woven fiber reinforced stuff with super skuckum shmoo for stickum! BTW you are #1 really the best channel on the tube!
I was down the engineering part of bangkok and there was a stall selling dremel styled cutting heads, for display he was using a electric dremel with a tungsten carbide tip, straight cut shank with a 90 degree flat face end, small diameter cutter, he had a beer bottle and was cutting swirled shapes in the glass with no lube, he went in dry! I was impressed at the ease of the cut, to start the cut he worked it in at a 45 degree and let the tip do the work. I dont think it can be cut on machine, to hard the vibration will case a resonance freq, free hand with a dremel, with the glass on rubber, then a cloth on top of the rubber, looks like you have lots of bits to test on, and chances are you have a dremel and a carbide tip in the man cave. Dont know if it will work on the tempered class but it worked on a beer bottle and that glass although not hardened it does have its own stresses.
pre-stressed glass is going to shatter when the surface tension is removed. So just use a plain glass bowl instead to save the effort of having to anneal it, difficult without a temp-controlled pottery oven or such. I've cut non-tempered glass before without problem. You use abrasive like you're doing (you can use a lot less if you make a small dam of putty to hold the abrasive slurry around the "bit" But for the bit, you chuck a piece of copper pipe in the drill. Prep the end by making a few diameter cuts across the bottom. The copper is soft enough to grab the abrasive and also to wear away and keep grabbing new abrasive. Taught to do this in shop class in high school of all places
Soda lime glass is tempered, so like you said the same properties that take place in a Prince Rupert's drop probably apply here too. It also isn't as capable of withstanding thermal shock as borosilicate glass. So I'm guessing the rapidly changing temperature from all the friction combined with the vibrations are probably to blame. Bonus fun fact: Pyrex does not make their glassware out of borosilicate glass anymore. In 1991 they changed to tempered soda lime glass.
Try using a flexible bit (aluminum bar) instead of the hole saw. The grit is what's doing the work anyway. The glass breaks because of the high impact loads from the interaction between the two very hard materials. If one material is soft, it absorbs the shock that would otherwise overstress the glass.
Fill your Pyrex with heated material to relax the stresses a little while you're cutting. You can try sugar heated in the oven for an hour or so at 500F until it starts to bubble. Fill your dish, then turn your drill up as high as she'll go and stand right next to it so you can keep a close eye on the progress. Everything should turn out fine.
I feel like spinning backwards was on the right track. In addition to all the commentary about internal stresses - I would think any glass would respond best to a grind type process. Use a plain tube instead of a bit with teeth - drastically reduce the stress concentration and avoid "cutting" type forces - all the work will be done by abrasion. I would think, however, that a tube for a "bit" would mean more load required on the quill. You could even add a few cuts to the tube for cuttings removal - but no teeth where it does contact just flat. And that advice is NOT backed by experience so take it for what it's worth which is obviously very little.
AvE you're the best brother. In another life time I from time to time would be asked to make water pipes for the fellas. They wanted them made from beer bottles and I knew the secret. Every time the bit would penetrate through the glass the bottle cracked. I learned through many errors that a piece of Scotch tape helped the glass resist expanding. And if you could rig up a drimmel with a stone bit to cut that radius it might just chooch. I would do a prototype except on account. On account my wife would string me up by the short and curlys if she caught me cutting holes in her Pyrex. Any way good luck professor schmoo.
fluted (to bring slurry into friction/cut out area) WOOD ring? soft enough not to cause resonance in the glass? slow as frig, similar to sandpaper, only more better. maybe cut out of pressure treated to prevent too much wood soakage/swellage. brings up a question. reason I think wood might work is because glass will damage wood more with the safe (same! frigging anti-correct) energy that metal will damage (break due to brittleness) glass. the obvious explanation is hardness, but is there a nomenclature to categorize what breaks what with what energy in what frequency, compared to what... what?
Don't know why it's breaking but it's certainly an interesting problem. In both cases it broke when you were a good part of the way through. My guess would also be internal stress which is overcoming the material strength when you get down to the last few mm of material. The downside of that is you don't stand much chance of ever drilling through it unless you can anneal it - at least it gives you a good excuse to build a furnace.
Your problem with frequency can be solved by surrounding the glass container with dissolved sure gel let it cure then cut the glass with your technique. It should work by dampening the harmonics . If not then I would try to acquire on a diamond bit or hole saw. Oh and plus your vids are awesome AvE...
Dad taught me to drill glass when I was a kid. The water is there for cooling. Never used Silicon Carbide. Put the glass under water (the whole thing), drill slow and pull the bit up after 5 seconds. 3-5 seconds to cool. Drill again, not too much pressure. When the other side gets thin you have to go light (so not to break it with the pressure or the bit) and less time with the bit engaged (because of heat).
"Tempered glass" is made by cooling the outside layer faster then the inside layer. The outside layer strains to compress the inside layer and the inside layer pushes against the outside layer. The two acting against each other and the molecular bond of silica creat surface tension. That surface tension can easily exceed 10k psi and once broken by an equal or greater force results in shattering. Annealed glass can be cut since it is evenly cooled and is not under excessive strain. You do not have to overcome the surface tension to break it, however, making it easier to break.
i did that with a piece of copper tube, the abrasive will embed in it and it'll grind away the glass. The idea is to clamp the glass between 2 wood planks, one with a hole already drilled used for guiding the "drill bit" Fill it with water and drill easy peasy, very common for drilling aquariums. But you cant drill tempered glass, it has too much stress.
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Probably no one will ever read this, but to drill glass like a champion you use slow speed very light feed, copper pipe, coolant, and abrasive! The copper pipe is soft enough to pick up the abrasive and carry it along the surface of the glass, scraping tiny glass particles away into the coolant. Using copper pipe sized to the diameter of the hole you want you will get a slightly enlarged hole, i.e. using 1/4 inch (.250) pipe could bore a hole .260 to .270 if you have a shoddy set up. This method will drill just about anything, so long as the abrasive powder you use will cut what your drilling. Diamond abrasive and copper pipe, plus time, equals a hole in anything thing you want. Coolant is a must and you really should use the coolant recommended for what your cutting.
For glass, sea shells, and some stone, try dishwashing liquid in water (soapy water) mixed with the silicone carbide abrasive. If you want a perfect finish on the front and back, drill half way through each side and meet in the middle of the item. Drilling all the way through glass will almost always chip the edges when it breaks through. Placing the item your drilling on foam or a sponge will actually minimize the breakout and chipping of glass when you drill all the way through it. Wish anyone the best of luck trying this! If anyone reads this and it helps I would love to know someone got some use of my 15 minutes thinking about this response.
I believe you are the winner of the best solution. I was going to suggest copper pipe myself. Your reasoning seems scientifically sound to me, an old lab rat.
bump
I've heard hardwood dowels also works.
commenting so it goes to the top, too
bump
Before you attemt to "drill" mineral glass i advise you to check for internal tension in the glass. How? Take 2 polaroid lenses and orient the first horizontally and the second vertically with distance in between to bring your object after the first and before the second lens. Without glass object light transmission throug the 2 lenses wil be very dim. When you bring a hardened glass object in between you wil see tension "flames". With any flaming visible every attempt to drill or grind is useless. Kind regards from an old school optician.
Nothing constructive to add here, so I'm just going to read all the other comments. I'm anxious to see who's an expert cutting glass on a milling machine using a hole saw. 😁
***** If you can drill a small pilot hole though the glass without it breaking, you've at least a chance of drilling the large hole successfully.
I think the Dollar stores have glass containers in similar shape and size; perhaps a cheaper glass might work better for this operation?
*****
Well, you have found an expert here - Over my past three marriages, I have literally broken tons of these Pyrex dishes.
Unfortunately I can't revel my trade secrets as I'm currently under a court order at the moment.
So.. apologies, I officially do not have anything to add either.
***** I also have absolutely nothing to add
hahahaha - Adam started it :)
I would have said something sooner but I was doubled over laughing. Your videos are gold. Fill the container with water. Thermal expansion is your enemy here. Maybe find an adhesive that takes heat well and glue the carbide to the hole saw. There's no need for wood cutting sized teeth for this so try cutting them down but leave some relief for slurry to exit.
tempered glass can not be cut. This dish was probably hardened for two reasons. makes it more resistant to damage from drops, and makes it more resistant to temperature changes. tempered glass basically has a large amount of exterior tension, and once released, it is explosive.
+Thomas Gunkler Yep, I work in a glass factory and one of the fun things we do to new guys working in cutting is give them a piece of tempered and tell them it needs to be cut down. The looks on their faces when the glass pops is priceless, especially if they know nothing about glass. Then ya gotta give them the old 'aw man that unit was hot... the boss is gonna be pissed' Good times.
+damedog19 fuck now I wont sleep :D
+huhhman not sure about that. the issue would be the edge of the cut glass. tempered glass must have a tapered edge. if it has a sharp edge, it won't last long. so unless the laser cuts a tapered (beveled) edge. not gonna last long.
+Thomas Gunkler
The fun part of proving this is using a polarized lens to see the stress marks. Cheaper the polarized sunglass, the better you see it.
+Thomas Gunkler It can be cut, I saw a guy do it in another video. His technique though was to go very slow and dont use constant pressure like AvE is doing. I think it might be cracking due to vibration building up, you need to lift up the saw/drill. All the other guy used was water too I think, he didnt use carbide.
Journeymen glazier here. That's glass is heat strengthened. You can either anneal the glass again or buy a non heat strengthened dish to drill. Any glass that has gone through any strengthening or tempering process can not be cut or drilled with anything. An option you can try is to melt a hole in it.
Also the dish can not be tempered as tempered glass does not like heat. So it is heat strengthened to withstand higher temps. Same process. Just lower temps in the oven and shorter quench time.
+Lunar Lancer oooooo. melt a hole! sounds awesome!
Great idea, Decim.
Gunpowder, it always works. Maybe not as intended, but it works.
patw52pb1 For KABOOMs of course!
there is a way to do it....you drop pyrex making it shatter into a million pieces...then glue the dish back together leaving out only the pieces where you need a hole. :) hope this helps.
Over all weight of the drilling piece should be minimal now you have heavy cuter heave chuck and weight of the turning shaft of the pulley all made a high impact on the glass to break . I think you can made initial cut how you cut and once you have a circular grove You can hold it against the cutting piece with you hand only so it absorbing all the vibration made Sure you ware glove.
How honest of you to show your results even when you're unsuccessful.
It's quiet puzzling, why the glass breaks all over the place all of a sudden, even in places that seem to be totally isolated from the point you apply a force to.
The Post Apocalyptic Inventor I just read your post in that German accent of yours... :)
That's a property of glass (and other structural plastics, like reenforced concrete) that has internal stresses caused by uneven or rapid hardening, often intentional. The desired effect is mainly to increase the strength and durability of the surface material, at the expense of the internal material's resilience. In short, once the internal stresses of the material become uneven due to a breach, it results in a chain reaction that pulls apart the rest of the structure, that approaches, sometimes exceeds, the speed of sound through the material.
For pyrex glass, this is over 5000 m/s.
A high speed camera filming at 25,000 fps would not capture two frames of the 8" dish fracturing, and 100,000 fps, only 3 or 4.
To get better than 1 mm resolution of a fracture in progress in pyrex, would require a frame rate approaching 6 million FPS: a restricted technology.
***** I had it coming ...
***** Well. After reading over 200 positive comments on my German accent a few days ago, changing anything in that direction would simply be a "bad business decision", not even talking about "staying true to oneself" and that kind of stuff. BTW: I had to smile when I heard you talkin' French all of a sudden. Must have caused some irritation :D
Nevin Williams
That is why you are not supposed to bang a hammer directly with another hammer.
They can "explode".
"Crystals" have this tendency to get stressed if they are cooled too rapidly and snap, releasing this energy, if you push them beyond their maximum tolerance.
Meaning they are not "plastic" in behavior at all.
I do not think that concrete forms crystals. Granite on the other hand will blow out if you heat it or hammer drill it.
AvE;
You got it when you referenced the Prince Rupert's drops. Pyrex is pre-stressed glass and that is why it is rock hard and tough to break. You are cutting through the outer stressed layer, stress now looking for places to go, and shazamm you have broken glass.
I know in lab class, the only way we could ever try to do anything with Pyrex was to heat that stuff up until it was just about molten and then try to manipulate it. And try to manipulate it is the key phrase. The techs in the shop who made glassware for the profs and grad students would laugh their asses off watching us undergrads try to make something.
Well worth the experiment.
Regards;
Ron Kluwe
Exactly. You need regular old glass. Pyrex is all about the internal stress.
Modern pyrex cookware is stressed soda glass, pyrex lab glass is borosilicate. Higher temps used to work borosilicate than "standard" glass but in itself it tends to be more durable.
Nobody seems to be explaining why tempered glass is hard to cut so I'll try my best. I'm sure someone else can do a better job.
When a substance like glass is heated it expands and when cooled it contracts. When it is cooled rapidly (i.e. tempered), the outer layer contracts rapidly and its tension places a constant compressive force to the inner glass. When the outer layer is damaged enough to fail, it releases all that compression simultaneously causing catastrophic failure to the piece. I don't think it matters whether the damage is caused slowly or quickly, only that it exceeds the tension balancing that compression force.
Prince Rupert drops are an example of what happens when that force is released. It's not the specific location of the damage on them that causes them to explode, but they are under such extreme compression which makes them so hard that you can only cause the damage the tail with conventional tools.
Unlike steel, I have no idea if/how tempered glass can be annealed (removing just enough of the temper to relieve the internal stress) but it would seem to be pointless in this case because the goal is to end up with tempered glass at the end.
Gorilla glass achieves some of the same surface strength results through a chemical process rather than a heat process, so it might be possible to do this kind of work on a gorilla glass piece if they ever make cookware out of it.
Andrew Crews And this is special how? You can bend the microscope cover plates too, which i believe is thin untempered glass. Resistive touchscreens fully worked based on glass surface bending, and they were not made out of Gorilla glass, they were made out of... not sure, untempered glass? Thermally tempered? I don't know, it was bonded to a plastic sheet usually and hard to break, but eventually they did break.
Glass fiber is VERY bendy.
Thin glass bends.
+Tim Gilbert Actually, when molten glass is chilled quickly, the outside freezes while the inside is still hot. Then, as the inside cools, it contracts and puts the surface under compression (the inside is under tension). This surface compression closes micro-cracks which are the source of all weakness in materials. A great book about this is _The New Science of Strong Materials or Why You Don't Fall through the Floor_ by J. E. Gordon.
This also explains why it breaks just before the hole is complete. The inner bulk strain is relieved, so the surface compression goes away, and the glass cracks.
+Chris Uhlik They use the same process for new cast car rims. Cool the outside and keep center hot when casting makes the wheels stronger by having forces under tension.
@@speeddr2000 I'm three years late but your absolutely right. If you cut through one they spring like crazy.
Glass artist here. If you can't be arsed to buy a glass bit, you need to go slow, use a softer material for the bit, (wood, maybe?) and put as much water in as you can get to help prevent thermal shock. It's also a good idea to back off every now and then to let more grit get into the groove and rinse the glass powder out.
Cool, but say he goes with the softer material, because shits and giggles, wouldn't that increase the surface area and make it harder to cut? Is it pretty much a case of "suck it up buttercup, she gonna take her time"?
The only concern with surface area is how much glass you're wasting. The "bit" isn't doing the work, it's all about the abrasive. You don't cut glass, you slowly sand it away or break it along an induced fault.
Dominic has sound advice. My diamond saw runs on nylon wheels. The glass get hot even with water and glass is no forgiving. Slow is key. Sanding the glass down.
The same technique is used to cut holes in telescope mirrors. However, you use a copper tube in place of your hole saw as the carbide will embed into the copper. If your glass dish is tempered, it is pre-stressed and will shatter if the surface is scratched or damaged. Look at it with polarized sunglasses, if it looks splotchy, it is tempered. Find one that isn't. Older ones weren't.
This should work
This is tempered (or toughened) glass, which has internal stresses which increases its resistance to fracture. Cheap tempered glass (usually cooled too quickly or at a wrong temperature) generally has uneven stresses throughout and can even spontaneously fracture (e.g., like some cheap Chinese glass patio furniture). This also means that if you relieve some of the internal stresses, they tend to fracture readily.
2 things. No. 1: yes it hurts for no reason, time for special old persons exercises every morning, shoulders and neck are the worst, where you retain the most tension. No. 2, don't know what the temperature of the glass was, cold glass cuts badly. I assume the water transmits heat away from the cutter so there is a minimal heat gradient across the whole dish, but it is almost as if the bottom has expanded so put the sides under tension. Cheers, Andy
Hi, I really enjoy your videos and your comments are a blast. I KNOW what the problem is because I have solved the exact same problem. BTW, I am a Ceramic Engineer (I bet you didn't even know they existed...). To start, Pyrex is an annealed glass, not hardened, intentionally to reduce internal stresses. What you are running into is due to intense ultrasonic vibration. This is revealed through the break pattern. If it was due to glass tempering, the piece would have shattered into many, many pieces. If it was due to local heating, you would see the crack propogating outward from the bore hole. These cracks originated at the outer edge and propogated inward. The starting points are also spaced out about 12cm apart around the top edge. All of this points to ultrasonic vibrations. The vibrations are caused by the grit rolling and skipping around at the blade/glass interface. There are a couple ways to address this. You were on the right track trying to embedd the piece to reduce motion. If you had embedded the edge of the bowl, it may have worked. Ultrasonic vibrations scatter in weird patterns and are hard to predict so even this approach is no guarantee. Another thing to do is replace the metal blade with something like a hard rubber or maybe a fiberglass impregnated plastic. And of course another thing is to go with a cutter that has the grit embedded to you don't get all that rolling and chattering around, which is what you were trying to work around in the first place. Even then, it is a good idea to dampen the edges. Good luck.
im stumped too, but this was a very interesting video.
so sorry that it did not chooch.
Works great on glass plates! I suspect that it's VERY difficult to drill cheap tempered glass. That stuff is like car side-windows: you can hit it with a hammer without damage, but any major scratch causes the entire thing to fracture explosively. So, your smooth SiC damage must not be causing problems, but something like a tiny fracture or deep scratch can set off the explosive disruption.
The physicists hole-saw is a copper tube.
With the soft copper, the SiC becomes embedded in the rotating edge, so it turns into a DIY diamond saw. I don't know if steel does this at all. Probably aluminum pipe does it too, but copper tube of desired diameter is easier to find. Get your lathe and whack out a precision drill from scrap aluminum rod? And I think a thinner slot drills faster, but I haven't tried that. Easier to apply large force using small weights.
Or this: perhaps try DIY pre-annealing, bake the glass at ?800F? or hotter? Get it up almost to softening temp, just below dull-red glow, then turn off the oven and let it cool over hours. That would un-temper the bakeware glass and remove the shattering effect ...but also make it far more prone to fracture if later dropped or heated (don't use un-tempered drilled glass for baking or cooktop!)
Or maybe its possible to find actual cheap crap glassware, non-pyrex non tempered. Find stuff that will shatter if used for baking. Without the gigantic internal tension produced by annealing, it will act like thick window glass, rather than exploding like Prince Rupert's drops. Total garbage glass can be drilled, and expensive borosilicate chem-lab glass can be drilled. It's the in-between stuff, the tempered soda lime glass that's the problem.
wbeaty what about a cerium oxide paste? also it sounds like the drill bit is striking the glass. maybe make a plywood base on the end of a shaft that just grinds the glass out?
wbeaty Tempered glass is like a flat Prince Rupert Drop. One can surmise that the only way to drill holes in it is to anneal it in a big oven then drill it when its gone cold. The re-tempering is allegedly done by re-heating it then blowing cold air on it.
Hey for that neck you're going to want to look up a video here on youtube. Search beginners yoga. The one that shows up from the Yoga Vidya channel is the one to do. Do it for a week. It'll set ya straight for a good chunk of the year.
I'm getting old too. Turning 22 in December
it's just from sleeping on a dodgy position
in*
Geof Dumas "Manly Men" don't do yoga! But I did hear that it helps the schmoo to flow!
Yep, getting old means that you hurt every damn day (and night) Voice of 70 years of experience.
I would make a "saw" from aluminum tubing, cut a slot in two sides. The breaking may have been high frequency vibrations.
Every time it freezes my stick sticks to the ice!
You gotta sneak up on tempered glass first.
If I remember right, Pyrex is under constant pressure, which is how it works. Something about having just the right amount of stress making it near unbreakable. I imagine that when you cut into it, it's breaking that tension as soon as you cut too deep, and snap, crackle, pop! I'd suggest using a non-Pyrex glass and see if you don't get better results.
I remember reading about this phenomenon. Tempered glass is stressed and once you get to the chewey bit in the center it wants to relieve it's stressed outer part, so as the saw makes it to the sweet spot it gets all kinds of wonky and the the outer stress is no longer the same and it says "screw this" and finishes contracting, and then the glass shatters. Work around - HEAT UP THE GLASS =)
Baaaa ha ha ha! That jump cut editing was hilarious! Thanks for the laugh. A bright spot on an otherwise blizzardy snow shovelling filled Ontario day. Cheers
The "new pyrex" el cheapo stuff is just tempered glass. Once you start cutting into it and releasing some of the stress, it's like a row of dominoes. You're going to need real pyrex ie borosilicate or just good ole soda-lime glass.
Borosilicate will take longer to cut through but comes with it's benefits. You could also remove the temper on the glass, but it's a whole lot less work just to get soda lime unless you need the properties of borosilicate.
Grind the teeth off the hole cutter, and just use a flat face?
Use a softer metal on the hole cutter? Some thick copper or mild steel pipe? The silicon carbide might imbed itself in the metal and make a nice grinding surface.
Heat the glass when you are part way though, and let it lose some of its temper? Maybe that will ruin it for the purpose you want.
Flush out the glass dust and put fresh grinding compound in?
Reduce vibration by using the end of a pipe that has been rounded off a bit? Reduce vibration by using the end of a pipe and filling the interior of the pipe with something to dampen the vibration? Plasticine? A rubber or plastic plug that has be pushed in far enough to clear the thickness of the glass?
Maybe try annealing the vessel before you cut it? Annealing for glass should be ~550C but there's a whole cycle of temperatures and times to make sure the glass is heated and cooled in a controlled manner. Do you still have the kiln or did you never get the bronze lining out of it? :)
From my humble amateur glass blowing experience, I would second Smidge on that anneal. > 514 deg. C for sodalime (standard glass) > 565 deg. C for borosilicate (pyrex and imitations) . With a kiln I would heat the container to temperature. Leave it a good 30minutes for the heat to chooch in there and let it cool down slowly. Of course there is also the real man's way to do it with a torch. I would start by heating the container with a "soft flame" (basically a flame with no or few oxygen that looks more like a lighter on steroids than a torch flame). trying to heat the thing as equally as possible. At first it's going to let soot on the glass, That's going to disappear as you get hotter (and start to let more oxygen in. To know when to stop heating, one could use a thermal camera, if it goes there. I would simply close the lights and and heat until the flame become street light orange (from the sodium burning or something). If you to see the glass glowing red when the flame is removed, that actually might be too late for a sodalime glass (melted), but that would make a great video anyways) . Let cool between a bunch of heat resistant covers or hot sand or in the barbecue, whatever.
Once cold, As said by many others, I would try using an aluminum or copper tube à a milling form. instead of an hard piece of metal. A softer metal will be more "compliant" if something hooks between the glass and the cutter. As you did, leave plenty of water for coolling in there. The gluing might actually be great for vibration damping and to hold the pieces and grinding juices from t'chouching on the lathe once done. Maybe lifting the bit frequently to make sure that the SiC grit get under the cutter and that I am not simply grinding glass with only the glass flour stucked under the cutter (SiC cuting glass = Sick fast, Glass cutting glass = Gloomy fast)
Good luck! (And if you append to reach the point where the sodalime starts melting ... keep heating the spot that you want to remove and stick a piece of steel tubing or wet wood in there to make your hole.)
I haven't read all the comments nor do I think that AvE is going to read this. A while back drilled out a few holes in single pane windows for AC vents. I used a similar fashion with a drill press and bi metal bits in reverse. I found that it works if you score the glass with a circle cutter and score a grid in the id of the circle you are cutting out.
can you heat treat the glass to de stress it? i have no experience other than my housemate and i tried cutting a safety glass plane about 1.5x2m needless to say... there was blood and a lot of mess
you cannot.
Use a smooth tube as the cutter, the teeth of the bi-metal saw are generating vibrations that work on the glass. A copper tube ought to work fine, as the carbide is the actual cutting tool here. Secondly, due to the heat treat of the glass, internal stress is high, so use a bit of clay around the edges of the glass to dampen vibration. Third, build a small (say 4" diameter) clay ring around the hole area and fill with the water and silicon slurry to localize the cutting mix. put water outside the clay ring to aid in vibration dampening.
I wonder if ooblek is good for vibration dampening
Add a small off-centered motor to the top of a small stick, place in the non-newtonian and vary the speed and voltage to watch the weird effects.
I only know one thing about tempered glass: You can't cut tempered glass.
But you do impossible things sometimes, so good luck.
Jeff Ratliff water jet can cut tempered without shattering, but i think it would ruin the purpose of the video...
Jeff Ratliff or maybe he could try reannealing the glass...
Thiago Ennes Water jet shatters tempered just the same as anything else. As soon as you compromise the outer layer, the internal stress causes it to fracture. The only thing that partially made it through was a laser before on colored tempered glass mostly because the laser, by melting the glass, would relieve some of the internal stress, but it the end, it shattered just the same. The only way to cut tempered is to untemper it.
Jeff Ratliff Not that you can't, you SHOULDN'T. Not because it's a harder but because it shatters at the slightest sign of damage.
***** That has been my experience as well. One of my hair-brained projects required a tempered glass tray, and after 6 attempts using similar methods to what AvE tried, we brought 3 more trays to the water jet shop, who warned us that the outcome wasn't likely to be successful. Only one of the three trays ended up with a clean hole without shattering, and it seemed like it would have done the job, but when it warmed up in the car on the way home, it spontaneously shattered as well. We ended up using a stainless tray with a tempered glass window.
I am so happy I can give you an answer!
Pyrex is tempered glass. Tempered glass is unique in that you can take a mallet to the broad surface of tempered glass and there's a good chance that hammer will bounce off and hit you instead. However, a moderately light amount of force either from the edge of the glass will cause it to shatter or, if a sharper fragment than glass is pushed into the surface (I saw a guy on a video shatter a piece of tempered glass by hurling a piece of ceramic from a spark plug at the surface).
Standard practice of cutting glass is to use either annealed or laminate glass. First you cut them very similarly to your idea except a reservoir is made for lubricant from glazier's putty and gasoline (don't use gasoline. that's what the old timers used -C2H6O is fine).
TLDR; Glass is cut before it is tempered.
+AvE Will diamond hole saws go through it? Ive drilled some pretty hard brittle porcelain that had the double fired surface tension thing going for it with em. I have a set
as long as the glass is not tempered.
Hey Brother,
The only thing I know about glass is that it breaks easy and cuts you really bad but, I can tell you from many years of experience that every thing you did to your body in life comes back with a vengeance and it seems to just happen overnight! Get used to it because it gets worse as time goes on!
Ray
I agree with the comments below about the pre stressed layer, this is probably a task that is really hard to do with Pyrex, cheaper quality dish may actually be better, but thats a guess. Also drilling the hole closer to the center, and away from the stress concentrating curved sides may help.
I did have an idea if you wanted to reduce vibration, you could secure the pyrex into a larger tub, and the put fluid around it (additional fluid in it is obviously gonna get in the way), to dampen vibration, possibly reduce possibility if sonic fracture. But that might be a solution to a problem that isnt present/the most pertinent.
Don't clamp it, at most use some silicone. Cut the teeth of the saw off so it is just a tube that might also help, a soft tube would be better as it will load with the abrasive. Reduce the down pressure, grinding can be a very gentle process.
But maybe the internal stresses are the issue and you just can't do it without some sort of annealing.
So glad I came across this video. We got a new "Pyrex" measuring cup because the paint on the old one wore off. A new one was cheap enough so we got a new one. I was going to clean up the old one and etch it so the writing would never wear off. I wondered why these things were painted instead of etched. I cussed the manufactures for being cheap and building in planned obsolesence. Before I etched the glass I answered my own question by remembering that the good old Pyrex was made from borosilicate while new Pyrex is made from tempered soda lime. Suspecting that etching would weaken the glass I decided not to etch the old measuring cup and just buy a new one every 10 years. This video and following discussion confirmed my suspicions.
Real diamond bits are dirt cheap these days BTW but that wouldn't have helped anything. It was the internal stress not the drilling method that caused the failure.
So after a little research to whats going on with your fancy bake ware here is that pyrex is now made using tempered glass, now that being said what is causing the point of failure for the hole. Well to get into that tempered glass is basically a form of stressed glass. so when your cutting your hole here every time you getting through or close to the center of the glass you giving the glass enough "weakness" (someone could of said that better). to shatter under is own internal forces. Now the fix buy cheaper glass or more expensive glass that are not under the internal forces that are found in you tempered glass ware.
I wanted a hole in some tempered glass cookware too. After failing a few times with the same results (didn't use silicon carbide powder), I asked a friend to help out. He just set it on a hot plate and drilled right through. The temperature does not have to be hot enough to melt the glass, just hot enough to relieve the tension. It cuts a bit faster, even though the Chuck was turning a LOT slower than I would have thought necessary.
Yep obviously defective glass. Great video though. I hope you picked those up at the store and not in the kitchen, just saying. I get the same level of success cutting holes in glass with a 45 acp but it is a lot faster. Thanks for the video.
cerberus I hear Hornady Critical Duty works well for that.
I've had great luck drilling or trepanning holes in glass etc using a similar method. Yes, SiC abrasive and water BUT instead of bimetal hole saw, I use copper tube or pipe. Dead soft annealed with some tri file fornication to get the abrasive to the cut. My wife likes to make desert serving tiered plates, each with a 10mm hole drilled. I do the drilling and have yet to crack or break one. Pine pitch makes great backing, melt it and bed the item to be drilled to cast iron platten etc. Keep it cool with some solid tap water if the shop is warm.
+AvE look up a polaroscope... itll let you see if the glass is stressed... Very simple to make
he already knew it was Pyrex, which is always stressed.
David Schroeder South Milwaukee, Whitefish Bay, nothing stinks like Cudahy! SM class of '87
If it's the new, cheap 'Pyrex', it isn't even Pyrex (Borosilicate) - it's just tempered glass. Corning sold the Pyrex trademark to a Chinese holding company, and now they're selling bogus product.
Yup getting old sucks that's for sure. As for putting a hole in glass try using a torch and slowly heating up the spot that you want the hole in. Or you can put an old socket in your glass pan then heat it up with the torch slowly until the socket melts a hole in the diameter you need..
I just recently thought about it but i believe you can use hydrofluoric acid to create a very clean cut without releasing the stresses in the glass and such and shattering.
I would recommend that you use the softest metal cutter that you have, but use, basically, a goop of the silicon carbide. Basically make a think paste of the stuff. and stuff it inside of the bit. As it goes down, it will deposit the mixture onto the cutting surface and will cut the glass with more ease. make sure that you also put some of the mixture on the outside of the bit as well so that you cover everything so that it will be the most effective as an abrasive. ALSO, from what I have seen with glass, you have to either go really really fast, or really really slow, never take the middle ground. when going fast, just remember that you don't want to hit the resonant frequency of the glass or else it will shatter without warning. Like you said, this glass is under stress, most likely caused by the tempering that factories do, because of this, I usually go on the slow path.
Hope this helps,
-UnforeseenLife
Did both drill attempts fail at roughly the same drilling depth? Is the hole saw bit tapered or flared inside to where at a certain drilling depth it grabs onto the glass cookie it's cutting out, jamming and causing failure? I think the baked in tension of Pyrex could be a cause too, but wouldn't it break sooner if it was? Wouldn't a glass blower burn a hole with a torch? You could try that, or a cheap glass bit hole to prove or disprove the tension theory. Slow speeds and a light torque setting could help? In my experience using a hole saw, it wants to rip the cookie out at the end, you could try drilling the bottom to form a deep score, then drill from the top. Put some abrasive inside the hole saw. Idk just ideas. Love your channel.
Bradford McAdams I was thinking that was probably it too
Your intuition is correct. New Pyrex from the past several years is no longer borosilicate, but tempered soda lime glass. They made the change in the U.S. to thwart people manufacturing drugs, can't recall which one unfortunately. The drug making process relied on the low CTE of the BSG to crash cool something, the soda lime can't handle it and will shatter.
I'm going to go with sonic fracture here, the teeth on that hole saw probably cause a vibration at the dish's resonant frequency as they bounce along the surface, maybe try a softer cutting surface with no teeth and lower speed, as others have suggested.
***** Woo! I'm helping! Let me know what happens... Well, I guess it'll end up in a video... So yeah, do that!
Taberwette! Your Quebec french is spot on! Awesomely entertaining yet educational videos!
It's only because it is crap that you got as far as you did.
Think of tempered glass as being like a balloon.
As soon as you put a hole through it, no matter how carefully, BANG.
I used to cut holes in the bottom of whiskey bottles for a carnival ride effect in a similar way. I made a dam around the hole with clay and chucked up a 3/4 inch copper sweat fitting in the drill press. It always worked.
I like what you tried to do. Reminds me of critical flaw size fracture in reverse - when the uncut section equals some critical dimension the thin section pops and propagates.
I have seen glass cut all sorts of ways with a water jet. Garnet + H20 at 50kpsi. Some smart guys morphed that technology into Garnet + liquid NH3 at 50Kpsi to cut up something special for a undisclosed client. It ended with tears and a call to the fire dept, but hey we have to push the envelop. Google patent 6080907 for the public domain version..
A Sears pressure washer should be able to do 3000 psi maybe that could work just more slowly than the 50kpsi slicer of doom.
That is freaking cool. My dad worked in the high precision optical instrument industry, and used to come up with some pretty cool stories of stuff hiding behind closed doors.
I have drilled through quart fruit jars with the silicon carbide slurry and a piece of copper tubing as a bit. The drilling action is very slow and use a pecking action on the feed. This limits the heat and allows fresh abrasive to flow into the cut zone. The soft copper doesn't bind in the cut. I use modelling clay as a dam around the work area to contain the water slurry. It's slow but it works.
Pro tip. Dont drill *tempered* glass...
Pyrex needs to be stress relieved. Gotta use something else that's not oven-safe.
Also, have seen cheap hole-saws at our (aus) big-box hardware stores for cutting thru tiles to fit over taps in showers, etc. might be the solution instead of toothed holesaw or diamond-tipped thing. They seemed to be a tube with abrasive stone glued on one end.
Being Pyrex I would be surprised if you could achieve what your trying, and if you did I would expect it to end up being a hair trigger from breaking soon after. Pyrex is just to highly wound up with stress.
Does it have to be glass? I think you would have much better success if you attempted what you are going with a ceramic baking dish. It would likely survive subsequent handling and temperature variations a lot better than glass.
You might be better off with a softer metal cutter as well. The old style cutters before cheap industrial diamonds use to use brass and sometimes copper, no teeth at all. (except maybe for a slurry slit). The abrasive slurry embeds particles in the relatively soft metal edge. (maybe use either very thin brass pipe or maybe a large copper pipe off cut). Also the resonance frequencies maybe a bit more dulled than with a hardened ferrous cutter so the rest of the work piece is not being punished as much.
I have also heard tell that sometimes they used slurry with almost razor thin Stainless steel shells. I think the principle was that the abrasive worked on both the sides of the cut but also wore the SS shell leading edge to an ultra thin ragged (microscope level almost) cutting edge.
Hey I'm a glass blower and i think the problem might be heat stress from the bit. I also work in a machine shop and know that end mills create a lot of heat especially with constant friction. It appears that the break occurs at around the same point of the cut and it could be that enough heat accumulates and causes a heat fracture causing the glass to fail. When i drill holes with an abrasive drill I usually back off to expend heat and clear the glass dust (chips) that are left behind. If it was tempered the vessel should have shattered as soon as the cut started.
What you need to do is get the glass super hot then dip it in ice water to prep it.
No, +Connieandblyde -- that is what was done at the factory, which is the cause of failure when the hole is almost through. The glass needs to be heated as hot as his oven will go, kept there a few hours to let the glass "relax". Then very gradually turn the temperature down, over the course of a whole day. At the end, the glass will have near zero internal stress, so it will not be prone to cracking.
That feed pressure assemblys friklen genius!
harmonics is a good suggestion of the cause.
You could hear the squeeking. The vibrations got to bad.
Possible the suggestion using a copper pipe as drill-bit would dampen the squeeking?
Lol both wrong he answered himself, it's tempered, impossible to cut tempered, will shatter every single time regardless.
I've drilled holes in glass but a little differently. I used 1" copper tubing as the cutter. I used some Clover lapping compound. I just smeared a bunch on the end, ran it at about 300 RPM and gently pecked at it. Let the grit do its work. I drilled into some beer and wine bottles. CLC is just silicon carbide and grease.
maybe it could be a frequency issue? possibly a vibration problem...
If this was a Prince Rupert's Drop issue (inside under pressure, but unable to defeat the outside surface tension), it would rupture and explode the moment the surface of the glass was broken, and the entire dish would likely disintegrate.
I work with tile and the diamond blades cut trough the glass no problem, I usually do it on the water saw. Your best bet is to get the same hole cutter like in the vid but naturally with the carbide tip for cutting porcelain, B&D makes nice ones that I have used before to drill trough hard full body porcelain. I would also recommend to put 3-4 layers of blue tape on the glass where u want to open the hole and fill up the glass pot with water.
You should've annealed the glass in a kiln before trying to bore through it.
+Kevin Jacobson yeah. im with this guy. though i think a kiln is over kill. you could probably put your oven on self cleaning with the dish inside and walk away. i've done a little bottle cutting and its some finicky stuff, glass.
+hexadecimil what do you do to cut ur bottles? I use GREENPOWERSCIENCE's method
+Shadowrcmegatech yeah! I watched a lot of videos before I started doing it and I found his to be the most informative. although he tells a few fibbs in his video "that would only take like 5 min to sand smooth." no. I don't know what he calls smooth... or 5 min but that's BS. second all I use is a micro torch. no water or ice. plus I use wide painters tape to keep the HAZ (heat affected zone) down to a minimum. I'm about to start experimenting with annealing or normalizing the stresses in the glass first before I cut. got a lot of broken wine bottles at the house. Which brings me to another fibb. the best bottles are easier. subscribe to my channle and I promise to post a bottle cutting video soon. you can seey set up, tools and method. might even break a few bottles too :D
hexadecimil holy shit! Is the painter's tape a common thing? I tried putting painter's tape .5in above and below the scoreline cause I thought it would help. I think it does at least a little bit. Where do you put painter's tape?
Yea it definitely takes awhile to sand the bottles. I put wet sandpaper on a foam floor mat and keep the cut bottles in the same place as I rotate them back and forth.
How close to perfect can you get the bottles using the torch? What % are successful? How often can you save both halves? For me it really depends on the bottle. Glass soda bottles are the easiest; sometimes a perfect scoreline can end up forming a crack most of the way around without any heating or cooling.
+Shadowrcmegatech yeah. it really does depend on the glass and apparently Coca Cola co. uses the best glass. wine bottles on the other hand are a real crap shoot. so far I'm 1 and 3 with those. beer bottles are the all arround best. though they break about half the time, they are plenty full and easy to score because of the often straight sides.
as for the painters tape I go about 1/4" below the line, which Google tells me is round about 6 mm (just in case your not state side) I do this to further isolate the HAZ as much as possible to the score line. since I don't care about the top of the bottle for making cups and vases I hesitate to say I've saved every one, even the ones where the bottle broke on me. I've got a stack of them. maybe I broke one. not sure. now I haven't experimented with quote, unquote annealing the bottle yet but I know that glass will melt round about 2000°F so I'm dubious 360°F in my toaster oven will do anything but I'm gonna try it anyway.
heat up the glass and the water? and keep it all warm constantly? ive made a bong from labware before but also i went to the home store and got a glass bit. and used a propane torch to keep it all nice a cozy warm. took a few beakers (9) but i did it. thank you to my old high school for the "donations"! ha!
just a tad too much chooch.
viol999 I have a slight feeling that AvE is indeed not a 15 year old, and knows when to stop chooching.
***** you just needed sweetchooch
I have drilled through glass using a copper pipe as a tool, Silicon Carbide as abrasive but you have to be patient and use a pecking action with the quill feed so you are grinding for maybe 1-2 seconds, lift the tool and let the abrasive replenish then go anoth4er 1-2 seconds. This helps cooling and keeps fresh abrasive in the cut.
You might want to chooch a plastic basin under the workpiece next time so that you don't spill abrasive slurry all over your mill.
steamgadget has it right about drilling. However, whenever I need a hole through glass I use my abrasive blaster w/200 mesh silicon carbide. Use a rubber or plastic washer as a template. Takes under a minute to penetrate 1/4" plate glass. I think you're right about the pre-stressing. Likely a result of improper annealing.
Où as tu appris à parler le français? 😊
+Hugo Delorme C'est n'est pas francais. C'est Quebecois :D
+AvE Tu sonne comme un Acadien de Shediac NB
+themirra2 c'est clairement ça, c'est beau du Chiac!
I've cut thru tempered/saftey glass by scouring the area to be drilled first, then going at it. Whenever I have clamped what I wás drilling it broke, I use fabric as a buffer between my clamp and material. It keeps the vibes down. cheap bits do best on glass.
Stupid question maybe but does your glass container with the hole in it need to be Pyrex? If your not heating it after I'm thinking of an aquarium type setup. Old window glass cut with glass cutter and make your own vessel by the same means, silicone the corners. Easy to drill that type of glass.
It's tempered glass. Made to resist impact. You'll want to slow the drill way down and keep the silicon carbide slurry flowing to the saw in a constant fashion and keep it cool. A hot spot causes the glass to expand and kaflooey. Lots more slurry might do the trick if you keep it chilled and mix it during the process.
I love the carefully calibrated drill lever weight! Exactly what I would have done after two minutes of boredom.
I got about three uses out of a 30mm diamond bit drilling through the bottom of very chunky whisky bottles. Made a dam out of bluetac and filled it up with water and added more when it started to heat up.
Very slow feed and very light pressure toward the end. Even then, I got a small chip when breaking through each time.
- Don't use metal, use something much softer, like a pvc-pipe (maybe copper or bronze will also work). With a hard material like steel, you will put the pressure on only a few points. The softer material will also hold the abrasive in place
- Glue the glass on a hard surface. I used thin spread hot glue on a steel plate.
- use oil as lubricant. Water is OK, but oil worked better for me. And only make a paste. You have to reapply it regularly.
- Reduce the pressure even more when you nearly through. Glass breaks from the surface, the smallest crack will travel trough the hole object.
I hope it helps.
it's the frequency of the cutter that's doing it!! pack the cutter out and I would put sand around it too
I once tried to cut a hardened table glass on a water jet machine. It was a security glass, the one that brakes in thousand peaces if you brake it.
In the beginning we cut with very low cutting speed and it cut fine. But as soon as we increased cutting speed it broke.
So from my experience of that project, what you could do is to try again with minimal force.
The stress in glass should not be underestimated. If you heat a glass bottle with a welding torch it will beak.
Pyrex sold in North America is no longer made of borosilicate (as AVE kind of noted). It is tempered (pre-stressed) soda lime glass and can not be cut without being annealed first. Can't be done, as soon as you remove the stress from the one side (in the cut) the stress from the other side will break the glass.
This will work fine on an old Pyrex dish made of boro, or some kind of untempered, not-for-cooking dish. Stock up on old 'real' pyrex at flea markets and such when you see some.
your french is awesome , im french canadian from quebec :) i do really enjoy your video , thank you!
I have used a cheap diamond coated hole saw from a good hardware store to cut holes in normal liquor bottle glass. The key is very low pressure and a slow but steady water supply to keep the heat down.
A few years ago I built a decently large Dobsonian Telescope 12.5" and I made it out of a big thick glass table top. First I used a hammer to bust it into smaller pieces because it was like 36X36 and 0.75 thick. Then I got some of those diamond dremel like cutting wheels from Harbor Frieght and used those to cut little pie shapes out of a rotozip diamond blade. Yeah I tried a normal cutting/ grinding wheel and that's a no go on diamond =). With a few of those pieces I attached them to the ends of a fly cutter so they were 12.5" apart. I used water and just let it go. I actually have a really short video of it on my phone somewhere. I also used a super calibrated auto feed system like you but I think mine might of been a gallon jug with water in it ;).
29.10.2015
Hi from Switzerland (the country next to Hilti-Land and with the nice money)
What about:
1. cut the big glass to small parts, one has to fit to your needs
2. fix it very very softly with clamps as if you would clamp your little finger ;-)
3. avoid or fix the sharp edges of the glass - do they have any tension left?
4. heat the fixed glass a little bit with a heat gun (no direct fire please) - if you use water - no cold water, rises the tension, use warm water to egalise the heat between glass bottom and the drilling circle
5. drill it, stop from time to time, heat it gently to egalise the heat between glass bottom and the drilling circle
6. start drilling, watch for cracks in the glass
7. if I'm wrong with this tip... do you best to "compliment" me in your unique way
8. try plan b: put a fitting small piece of glass in the lathe and do as the young Dr. Frankenstein: try it to drill - may be from the inside to the outside?
9. Important: this advice is given freely and if you follow it fully or partially - it's on your own risk and safety - you are a Canadian so you have to have a brain and take a good use of it (xxx sticks paperclip in ele...) so no fat chance to see me in the front of a jugde or court...
I used to fret over that "I can't do as much as I could when I was younger" thing. When I was 21 y/o, I could to 135 pushups. Now I'm 62. I pay people to do pushups for me. Thanks - Lumpy
First video I ever watch on your channel.
I have been hooked ever since! Your channel is incredible and makes me happy to watch
Might be good to put it in a kiln at 1200f and leave it for 2 hours then shut the kiln off and let cool naturally, this will get the pyrex hot enough to flow without losing shape and will remove the stress that is trapped.
Alrighty boss I haven't had the need to try it out on Pyrex or tempered glass. But it does work and quite well on regular glass. I learned this trick making bongs out of Miller High Life bottles. Tape yes that strip of plastiqu with the sticm on the back. And for that dude I recommend heavy duty packing tape. Maybe even the woven fiber reinforced stuff with super skuckum shmoo for stickum! BTW you are #1 really the best channel on the tube!
I was down the engineering part of bangkok and there was a stall selling dremel styled cutting heads, for display he was using a electric dremel with a tungsten carbide tip, straight cut shank with a 90 degree flat face end, small diameter cutter, he had a beer bottle and was cutting swirled shapes in the glass with no lube, he went in dry!
I was impressed at the ease of the cut, to start the cut he worked it in at a 45 degree and let the tip do the work.
I dont think it can be cut on machine, to hard the vibration will case a resonance freq, free hand with a dremel, with the glass on rubber, then a cloth on top of the rubber, looks like you have lots of bits to test on, and chances are you have a dremel and a carbide tip in the man cave. Dont know if it will work on the tempered class but it worked on a beer bottle and that glass although not hardened it does have its own stresses.
pre-stressed glass is going to shatter when the surface tension is removed. So just use a plain glass bowl instead to save the effort of having to anneal it, difficult without a temp-controlled pottery oven or such.
I've cut non-tempered glass before without problem. You use abrasive like you're doing (you can use a lot less if you make a small dam of putty to hold the abrasive slurry around the "bit" But for the bit, you chuck a piece of copper pipe in the drill. Prep the end by making a few diameter cuts across the bottom. The copper is soft enough to grab the abrasive and also to wear away and keep grabbing new abrasive. Taught to do this in shop class in high school of all places
Soda lime glass is tempered, so like you said the same properties that take place in a Prince Rupert's drop probably apply here too. It also isn't as capable of withstanding thermal shock as borosilicate glass. So I'm guessing the rapidly changing temperature from all the friction combined with the vibrations are probably to blame. Bonus fun fact: Pyrex does not make their glassware out of borosilicate glass anymore. In 1991 they changed to tempered soda lime glass.
Try using a flexible bit (aluminum bar) instead of the hole saw. The grit is what's doing the work anyway. The glass breaks because of the high impact loads from the interaction between the two very hard materials. If one material is soft, it absorbs the shock that would otherwise overstress the glass.
Fill your Pyrex with heated material to relax the stresses a little while you're cutting. You can try sugar heated in the oven for an hour or so at 500F until it starts to bubble. Fill your dish, then turn your drill up as high as she'll go and stand right next to it so you can keep a close eye on the progress. Everything should turn out fine.
I feel like spinning backwards was on the right track. In addition to all the commentary about internal stresses - I would think any glass would respond best to a grind type process. Use a plain tube instead of a bit with teeth - drastically reduce the stress concentration and avoid "cutting" type forces - all the work will be done by abrasion. I would think, however, that a tube for a "bit" would mean more load required on the quill. You could even add a few cuts to the tube for cuttings removal - but no teeth where it does contact just flat. And that advice is NOT backed by experience so take it for what it's worth which is obviously very little.
AvE you're the best brother. In another life time I from time to time would be asked to make water pipes for the fellas. They wanted them made from beer bottles and I knew the secret. Every time the bit would penetrate through the glass the bottle cracked. I learned through many errors that a piece of Scotch tape helped the glass resist expanding. And if you could rig up a drimmel with a stone bit to cut that radius it might just chooch. I would do a prototype except on account. On account my wife would string me up by the short and curlys if she caught me cutting holes in her Pyrex. Any way good luck professor schmoo.
fluted (to bring slurry into friction/cut out area) WOOD ring? soft enough not to cause resonance in the glass? slow as frig, similar to sandpaper, only more better. maybe cut out of pressure treated to prevent too much wood soakage/swellage.
brings up a question. reason I think wood might work is because glass will damage wood more with the safe (same! frigging anti-correct) energy that metal will damage (break due to brittleness) glass. the obvious explanation is hardness, but is there a nomenclature to categorize what breaks what with what energy in what frequency, compared to what... what?
Don't know why it's breaking but it's certainly an interesting problem. In both cases it broke when you were a good part of the way through. My guess would also be internal stress which is overcoming the material strength when you get down to the last few mm of material. The downside of that is you don't stand much chance of ever drilling through it unless you can anneal it - at least it gives you a good excuse to build a furnace.
Your problem with frequency can be solved by surrounding the glass container with dissolved sure gel let it cure then cut the glass with your technique. It should work by dampening the harmonics . If not then I would try to acquire on a diamond bit or hole saw. Oh and plus your vids are awesome AvE...
Dad taught me to drill glass when I was a kid. The water is there for cooling. Never used Silicon Carbide. Put the glass under water (the whole thing), drill slow and pull the bit up after 5 seconds. 3-5 seconds to cool. Drill again, not too much pressure. When the other side gets thin you have to go light (so not to break it with the pressure or the bit) and less time with the bit engaged (because of heat).
"Tempered glass" is made by cooling the outside layer faster then the inside layer. The outside layer strains to compress the inside layer and the inside layer pushes against the outside layer. The two acting against each other and the molecular bond of silica creat surface tension. That surface tension can easily exceed 10k psi and once broken by an equal or greater force results in shattering.
Annealed glass can be cut since it is evenly cooled and is not under excessive strain. You do not have to overcome the surface tension to break it, however, making it easier to break.
Not gonna convince me that was cheaper than a diamond hole saw
i did that with a piece of copper tube, the abrasive will embed in it and it'll grind away the glass.
The idea is to clamp the glass between 2 wood planks, one with a hole already drilled used for guiding the "drill bit"
Fill it with water and drill easy peasy, very common for drilling aquariums.
But you cant drill tempered glass, it has too much stress.