Transforming a Pressure Pot for Resin Casting
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- Опубликовано: 7 сен 2024
- I attended a seminar last spring at the Oregon Woodturning Symposium about casting resin. One of the takeaways I got was that I needed to find a used pressure pot to do resin casting in. When casting resin under high air pressure, the bubbles get squeezed down so small that you can't see them and you get a clear resin cast. I found a pressure pot on Craigslist and picked it up for $25. It needed some work to be converted from a paint pressure pot for paint spraying to one for resin casting. There was a bunch of paint spraying functions with the pot that I did not need so I remove those parts. Then I chased down all the leaks in the pressure pot from the different attachments and also made a new lid seal. It now seems to be working and I did a test with some old resin that turned out a little bit yellow. The bubbles in the cast that I did in the pressure pot are definitely smaller but they did not quite completely disappear. I hope this is because I was using old, somewhat thick resin and with some fresh resin I hope I will get a clear cast.
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3:11 perfect demonstration why the direction of the winding of the tape is important :-) when you screw the cap back on it goes against the winding of the tape.. unwinding and bunching it up..
@Bob Ross Think... "left handed hammer". "He meant to say "tape" versus "tap".
Yup, learning that bit of information made using teflon tape much easier for me.
It's also much easier if you unwind off the backside of the tape. That way you're not fighting the length of tape getting farther away from the spool as you unwind.
For sure. Its triggering my OCD. He probably did it on purpose just to get a response out of us... It worked. Damn.
Everybody Screws it up the wrong way at least once.......!
I love your videos Frank. But please be careful with modified pressure vessels. You should definitely have a pressure relief valve in that tank (which you may have removed) and make sure its rated/tested for your working pressure. A regulator on the inlet is not enough to be safe. All that rust on the inside is a bit worrisome as well. If that tank is overfilled, or fails under pressure, it will be a really serious (even deadly) accident.
Angry Nimbus Woodcraft
I hate the safety police, but this is no joke, I’d be very disappointed if I never got to see another Frank video.
I'll second that comment about pressure regulators failing. And they fail into full pressure of the input source. I've had it happen twice. Once on the air compressor regulator, and the other on an Oxygen tank with 2400PSI. Both blew out the diaphragm. Good thing on the Oxygen, this preventing the regulator casting from exploding.
@spim randsley That cap he made is fine - it is not going to suddenly fail. It may develop a leak but it is not going to break. The rest of the pot however is in unknown condition. Old and rusty are not what you want in something that holds pressure.
I do agree relief valves are not optional and this is not something to be taken lightly. Fortunately however for resin casting you don't need much pressure at all. So this should be perfectly safe enough if used correctly. At the pressures needed to make a good resin cast the most catastrophic failure won't be that dangerous - still that won't save you injury if it fails in an air cannon like way into an unfortunate location. Not a fan of the Al plate, but for such low pressures it should be fine as long as a nice low pressure relief valve is added.
Im mostly concerned about the structural integrity of the tank being that it is rusted and the seams may be weakened. Even at low pressure, a catastrophic failure can send shrapnel, brass fittings, chunks of the compressor tank and small bits of steel flying at high speed. If you are right next to it when it fails, its gonna be a very bad day.
I dont want to come off as the safety police. We all take measured risks every day. I only mention it because Ive seen the result of a compressor failure, and Frank mentioned that he doesnt work with pressurized air very often. I'm no engineer, but two wise statements from the illustrious Ave are ringing in my ears right now:
"You are the softest thing in the shop"
"Dont mess with pressure vessels"
This Old Tony is a bike mechanic now and Frank is doing pluming. I stop whatever I am doing to watch these two anyway.
And AvE is making busts of Sean Connery. ;)
@@FieroFats going to have to go hunt that one down... the world is going sideways!
The soft background "Damn it" @9:18 gives me life.
Try using the pot as a vacuum chamber. You can quick dry small wood parts quickly. and evacuate bubbles from castings.
Yes, I think vacuum is better than pressure for casting. But the issue is that it makes a mess if the user is not careful. But the results are much better. Maybe he can it make a pressure and vacuum chamber.
A large part of your genius is your relentlessness. Bravo!
oh the joys of making something airtight!
omg I want to wire wheel the rusty inside of that lid so badly.
CJC Or have it sandblasted. Any cracks or weak spots would be more evident then.
I was thinking the same. His shop is amazing but he leaves that rust in there to keep eating away at the pressure pot. Also the rust flakes can drop into his work before it sets.
Dear Frank,
it is always a pleasure for me to watch your patience working on your projects.
avoiding air bubbles inside the resin with pressured air is not recommended.
I worked in a department for manufacturing high voltage isolators from resin.
We evacuated the resin after the mixing process for about 3 hours in a vacuum chamber before
starting the casting process.
I recommend to use vacuum too.
Best regards from Hamburg in Germany
Tom
That is of course absolutely correct when considering the breakdown voltage on various dielectric materials. But Frank is using resin casting for its other more visual properties.
Thanks for showing the troubleshooting process. That is the best part.
Like they say, if at first you don't succeed, try and try and try and try and try and try again. VERY WELL done Frank. Way to hang in there.
Frank, I love your videos. The fact that you leave all of your "learning" in them for us to see is inspiring, unlike the heavily edited production videos all over RUclips. It feels quite like real life for the rest of us, who go through the same struggles. Keep it up!
Wen you pour the mixed resin allow it to flow into a thin stream by holding the mixing cup high enough. This causes a lot of shear force on the fluid and pops the bubbles.
Oh, that’s good, thanks.
Won't heat also get rid of the bubbles? I've done resin with a heat gun and gotten it pretty well bubble free and perfectly clear so this whole video was vexing to me
Hali's Hobbies
I’ve been playing with table top epoxy, I think the heat only gets the bubbles on the surface.
HEAT IS GOOD FOR SHALLOW RESIN. DEEP CASTING YOU'LL NEED TO USE SOMETHING LIKE HIS SETUP
@@yourstruly6548 A small torch will also work. A heat gun will push the resin around because it's blowing hot air, which is fine in some cases but a torch will allow you to pop bubbles without pushing it around. Heat makes bubbles rise and pop because the moisture in the air of the bubbles evaporates and it wants to rise and escape.
Hi Frank,just a quick tip from an old plumber. Put thread tape on clock wise to go WITH the thread when screwing. You put the tape on anti clock wise when you put the cap on. That just chews the tape up when screwing. It will still work if you put heaps on which is only waste.
Another great video. I’ve learnt a lot from you. Thank you.
Frank, thanks for showing the trial and error. It gives me a more realistic view of what it takes to make something... all the other montage videos make it look like everything just works when you make something and, in reality, it NEVER does. Thanks again!
Great video... Remember to wrap the sealing tape clockwise with the treading... @3:08
jrainmaker19 I noticed this as well
Frank, another great video, but I must add my caution to the ones already here. Please be sure that you have a working pressure relief device on that thing. None of us want to see anything bad happen in your shop! Your family needs you.
....
Oh please. Like that thing is going to blow up before it leaks?
@@jomgelborn As long as it leaks faster than you're putting air in.
Love you videos---and also love your humility. I love that you don't profess to have all the answers. Your honesty is refreshing and it makes it fun to watch! Keep up the great work!
What I really appreciate about this is watching you troubleshoot and solve problems when you're out of your element while leveraging the things you do well.
I also really liked the audio-masked exclamation when that second bit broke. I cracked up and thought, yeah, I'd do the same. Hahaha.
I have been experimenting with vacuum and pressure for about five years now my solution is vacuum the two parts of the resin before you mix them not after. When you mix them do so carefully trying to incorporate as few bubbles as possible then put them in the pressure pot at 50 to 55 lb and you will have a clear casting. The relief valve is still in place it's that skinny thing with the little rod sticking out of it. If you're worried about it functioning you could replace it. But that pot can handle 60 lb easily. Best of luck in your future projects. Something I did was rap the pot in an electric blanket to help the resin cure. Resins like alumilite have an exothermic reaction which will cause a lot of bubbles. I find art and glow resin to work well at a reasonable price and is a nice clear product.
I especially enjoyed watching as you continued to focus on resolving each challenge as they presented themselves, Frank! Good on you for hanging in there.
I must admit you definitely have a way with editing. Perfect job. I noticed in the background your flat surfaces have become a shelf, storage area. No matter how hard I try my large tools if not used every day become an convenient place to set stuff on. Glad to see in some respects you are mortal like most of us.
Can’t wait to see your first attempt !!!
I began watching Frank's videos for the woodworking, but I have learned so much other stuff that I don't miss any of his videos. He's the only content creator who always has my full attention and he is wonderful. Thank you, Frank!
I like how you demonstrate that using a CNC isn't as easy as most people thing. I think most people thing you just drawn and hit print and really there is a lot of experience and skill that goes into making a cnc work as smoothly as it usually does for you.
I admire your persistence! In our shop we let the resin degass using a vacuum chamber before we pour it in the mold, then finally let it set in the pressure chamber. Works great!
Fascinating to watch you eradicate issues one by one, and to see you use all your nice tools. Now that's over, PLEASE throw that ticking bomb away and go buy you a pressure pot! :)
Just went through a similar process on a used pot. Leaks, dead gauge, more leaks, etc. Finally got it all air tight and functioning properly. So you have my sympathy for all the trial and error needed to get your pot functioning properly. Low purchase price made it all worth it!
thanks Frank. Geez, it amazes me every time that I watch your videos that you can take something like this, or the big water container or just about anything and make it interesting.
Resin claims another victim! Welcome to the void Frank. :)
I applaud your patience and perseverance 👍🏻
Hi Frank, it was great to watch you problem solve and fix the chamber. Sometimes though you get what you pay for ... Cheers
Frank, you might consider doing a hydrostatic test of the pressure vessel to give you some confidence that it is safe. This lets you take the container to something like 150% of the working pressure without the risk of a catastrophic explosion. And after its done, you'll be able to see if the container comes back to the same volume.
How does one do this test?
What a patient guy. Great work!
I love your sense of humor, you find enjoyment in everything you do, thanks for sharing.
Hi Frank, enjoy your videos. This may already be listed in the ton of comments below, but there are so many, I don't have time to read them all. The best practice I have seen to get clarity is to first put is under vacuum. This will remove many of the bubbles as it causes them to expand and float up then pop. You have to do it slowly as it will cause the resin to "boil over." After you put is under vacuum and get the "boiling" to almost stop, then put it under pressure to shrink any remaining bubbles. Best wishes.
I think you sorted it in the end, I love the knobs to help, you should make some more so that you don't have to change them around. Good luck with your castings.
Can't wait to see your resin projects! :)
I love this error searching and the whole process of making it work.... thx for another great video :)
Always a pleasure watching your videos Frank! Good Luck with your future projects Buddy! Have A Super Week!.....Gus
I absolutely LOVED your take on a restoration video. You had all the necessary tools! Please consider doing more videos like this in the future!
I am a pressure vessel and pipe Inspector in refineries, what we use is a soapy water to test for leaks.
Have fun Frank! My whole channel is pretty much dedicated to pressure resin casting, so let me know if you have any questions.
Binks pressure pots are the best of the best. They are ASME rated for 110 PSI I believe. Obviously that’s voided with your aluminum contraption but regardless, you got a fantastic deal on yours.
I've been thinking about this too, but I'm interested in first pulling a vacuum, and then pressurizing. The advangtage is that the vacuum would draw air from crevices, and then the pressure would drive the resin into the crevices. Pressure alone, just compresses any air bubbles - it doesn't remove the air. For many resin castings, this may not be a problem, but sometimes i think that pulling a vacuum first would be a good thing to do.
Great video!! That’s a cool old tank!! 👍👍
Hey Frank, although I have no interest in making a pressure pot, I gained a lot from this video. I admire your thought process and patience when facing obstacles. I started watching your channel for the woodworking aspect, but find I'm learning more from your way of thinking. Thank you for sharing this with us.
It was great seeing how you went through the trial and error process with this.
When using teflon tape, you only need to do one wrap around the thread. Pipe threads are tapered and the teflon allows the mating thread to screw on further thereby making a better seal.
You should try and see if you can make it work as a vacuum chamber too. Always good to have that avalible as an option if you need it.
Frank, I also love your videos. Let me suggest that you use the same vessel for vacuum. It will be a hell of a lot SAFER as you will only apply one atmosphere. And specifically, you can create a greater effect on your bubble elimination by expanding them and raising them to the surface. Even a 2% vacuum (really coarse) could be as effective as a 30 Bar pressure - something your pot should never do. I am sure you can find a used HVAC pump. The exact result depends on the resin surface tension. One side bonus is the vacuum will pull the lid closed and all your other fitting will work well enough. A vacuum can be really useful for lots of projects (for another time).
Also the reason there was bubbles in your test piece was because there’s moisture in the paper of paper cups. Moisture causes problem with any resin, but especially Alumilite, which I could tell is what you used.
If you used a plastic cup, it would have came out perfect.
Have fun Frank, I know you’ll love it!
Frank, if you can't remove the remaining long tube inside the pot, you can cut it off. It isn't needed and will get in the way of some things you may want to put in the pot... like a rack for getting your molds in and out of the pot more easily. The most important thing is knowing the limits of your pot. Based on it's current condition I wouldn't take it above 60 psi, but for most resins that should be fine.
Thanks Frank, that was quite the journey, finding all the various leaks. Hope you find the reason for the stubborn bubbles, might very well be the old thick resin. Looking forward to resin involved projects.
Good job. Persistence pays off.
Such a pleasure to watch you go through the steps in videos. I also like old power tools and find many challenges in repairing them for use in my shop. But that's half the fun too. I also love that you don't have a ton ads on your videos. Most people are getting so many ads that I dont even watch them anymore.
Thanks for all that you do, and keep up the great work. By the way, I have a little CNC envy. That is a very nice setup.
For what it's worth, I've had amazing results from vacuum degassing resin before pouring. I get perfect bubble-free casts without using pressure pots.
That was my first thought. It seems like this would be a much easier (and smaller footprint) solution. Thanks for letting me know it works.
vacuum is safer than pressure, I sold a couple of these on ebay and they both used vacuum for resin casting.
@Some Guy of its done right you won't even see the bubble with pressure, and I disagree about the vacuum being better, it takes a lot longer to cycle through and get all the air bubbles out, so shorter casting times are not possible and you need to worry about it bubbling over.
Implosions can be dangerous too. I'd direct you to ask submariners, but any with fist hand knowledge are not saying much anymore.......that said, vein severing or eye piercing shrapnel is significantly less likely.
@@gregmislick1117 Luckily, nobody will be inside this apparatus, unlike submarines..
@@gregmislick1117 submarines also see way higher outside pressure than a vacuum chamber at sea level.
That being said, once i evacuated a glass jar in my kitchen, luckily it failed while i went to the bathroom.
There was a loud bang and thousands of small glass shards all over my kitchen. :D
Try putting the resin under vacuum first - to pull out any trapped air in your resin whilst it is in your pouring container, then you can pour into your wood/object on the bench. By all means you could also cast under pressure for a double-whammy bubble size reduction, but you restrict the size of your cast items to those that fit inside your chamber.
in resin casting a vacuum chamber works wonders BEFORE you pour and a pressure pot while curing... IF you want crystal clear castings
This, the vacuum does a better job of getting rid of the bubble, the pressure pot pushes the resin into the corners of a part and helps with the tiny bubbles that are left post vacuum.
I think we have all experienced projects that turn out like this, thanks for sharing
What a neat project! I'd really like to see a return to this pot where you work on restoring it/modifying it some more! Maybe attach those wooden handles, remove all the rust and resurface it, etc. Put your own twist on your new toy, ya know?
That teflon threading tape is not a sealant like many people think it is. It is anti-seize, drinking water grade anti-seize. You only put 1 wrap of it around the pipe and helps disassembly in the future. The seal is made with the taper of the fixtures being as tight of a fit as possible, if it leaks without the tape, it will eventually leak again with the tape.
Epoxy works pretty good for sealing those threads. Good info in this video....thank you!
Frank, I loved this video.
I agree with some of the other commentors; a pressure relief valve (which it appears you still have, the 2-1/2 to 3in brass fitting standing beside the base of the gauges) only works when you reach its designed pressure. You might want to test or replace it. But if the tank has a weak spot that will give way at a lower pressure, well, I suggest you use it only when no one - especially your wife and kids - is in the building. FYI, multiply 50psi by the surface area of the inside of the vessel; it's an eye opener.
Hi Frank, I noticed you using Teflon tape. Next time hold the pipe in your left hand put the tape on your thumb finger...etc so that it rolls from the bottom of the roll hold the end with your thumb and starting two threads from the end start rolling the tape on go towards the end of the pipe till your only one thread from the end then start rolling the tape back up the thread. There are usually 11 threads on the pipe only go back 8, 7 works and once there hold that part with your thumb and pull the tape till it brakes than give it a rub with your thumb and you're done. That way when you thread the fitting on to the pipe the tape stays put and makes it look just like a Pro did it. One more thing I noticed you put tape on the male end of that brass fitting ....never tape that part brass on brass makes a really tight fit. Hope you find this interesting. Really like your work.
I love that you share your lessons learned. Thank you.
Try pulling a vacuum on the chamber to get most of the bubbles out of the resin, and then put it under pressure to shrink the size of any remaining bubbles. This will also help present to penetrate the pores of whatever you have mixed with it, and will make for a better bond in the long run.
Resin projects are really cool, excited to see what you create with it
Now that you have a pressure vessel, you could add a vacuum pump and make it a two-step process. Mix the resin, hardener and pigment, then 1) pull a vacuum to de-gass it and 2) cast it and pump a pressure to make whatever bubbles remain very small.
Great video as always Frank! One of my favorite things about your channel is the narrative nature. We are going along with your journey as you figure out a new project, and I love seeing the ideas and the failures as well as the end result.
I will be very interested how this positive pressure environment works out, and whether or not you try a vacuum system to compare :D
Not sure if this has already been stated, but I have a similar pressure pot that I use for painting in our metal fabrication shop. In addition to the rubber seal at the top, my supplier offers drum liners which are a sort of thick plastic insert that go in the pot and have an edge which folds over the top of the drum. This helps seal and prevents the metal edge of the drum from cutting into the rubber seal. I would be happy to send you one to try if you are interested. My pressure pot is meant to hold a 5 gallon pail of paint, so I am not sure if it would fit yours. Thanks for all of the great content!
Can't wait to see your new casting projects awesome awesome thumbs up my friend
Wow, kudos for your perseverance - now we await some masterpieces of resin casting!
That's a steal what you paid for that pot. I work on those on a daily basis and that particular pot is not cheap. Great video
If you're still getting bubbles try degassing the resin in a vacuum desiccator hooked up to a HVAC vacuum pump before you pressurize it to cure. I got both for $150 total and they make a big difference. Also, pour slow and high like others have mentioned.
Frank I have been DYING to see what you could do with some resin projects!! Looking forward to this!
One tip for pneumatics the thread sealing tape when putting it on threads leave 1-3 full threads uncovered so threading other parts on is easy. Just makes your life a headache if they dont thread
Plumber here. Soapy water in a spray bottle will pin point any leaks with bubbles.
Great video as usual!
Edit: commented too early and see you already used that trick haha.
advertised for $85, bought for $25. Brutal negotiator!
Omg I love all your videos but this one scared me to death! I'm a kid of the 60's & I remember horror stories of pressure cookers blowing up. All that kept playing in my mind was Marvin the Martians voice "Where is the Kaboom? There was supposed to be an earth shattering kaboom?!!!"
You have a fantastic shop!
Excellent as usual!!!
That video could have been my experience. I went thru the same process but it kept leaking. I had a small leak along the rolled edge on the bottom. I tried to weld it and to my surprise was sealed with solder. It all melted out. I ended up buying a new one. Good Luck
Frank, You are killing me on this one! You are a genius, but RTV 108 from McMaster Carr will solve almost all of your problems.
Cut off both tubes in your pressure pot first and then attend to the gasket. Use .125 thick BUNA-N sheet and cut it to size for the gasket - no need for the router as most of us don't have one. I love your stuff, man, but this should have been a few hour's worth of work tops. A relief valve set to open at 50 is very important. I found out the hard way....Boom and impact to my wife's rear quarter panel. Lots of explaining thereafter.
Cheers!
i really enjoy your videos Frank, thanks for taking the time to make them
Would recommend not going up to 60psi, thats usually around the limit of most pressure pots and can become dangerous. With resin you can easily do the job with 45-50psi no problem.
I believe that I would install a relief valve on it for safety just in case it is ever over pressurized.
@@robstephens Yeah, I have one on mine set to go off around 57psi
I was using a 2 part casting silicone to pour a seal on my pressure pot which works perfectly. Just level the lid and pour it in the groove and let cure.
And as others said, pressure vessels are no joke!
Nice size pot. Mine is 5 gal. and yours may be bigger. I made a cradle for mine and use it horizontal most of the time. I fit a shelf in a little below center. I can always use it standing up but never really need to.
My molds are 12.75 and just fit in for my mills.
Oh my, I knew the RUclips safety police would be in full force but come on guys. The guy is an architect, you don't think he understands the risks associated with working with high pressures? The cap he removed was for adding paint without taking the entire device apart! The safety valve is still attached, it's part of the regulator setup. You can clearly see it in the video.
He didn't test it with water first tho...
Everyone is coming from a place of care for Frank! And just because Frank is an Architect and clearly an intelligent man, this does not mean he knows all the ins and outs of pressure vessels- which clearly shows in some of the smaller details. Don’t be so quick to jump on people for not wanting Frank to unintentionally kill himself. Honestly, this attitude is more dangerous than this tank.
The thing that makes pressurized containers so dangerous is that they don’t appear to be so. Stay safe
In SCUBA class, we learn about Charles' Law. Essentially that the volume of a gas is proportional to the pressure exerted on it. At the pressure you're working at, the bubbles are only going to be reduced to about 1/4 their size. Understandable why they're still visible.
That drag knife is the coolest thing!
When casting resin another way to get clarity is to put the resin in a Vacuum chamber before you cast it. The Vaccum pulls out the gas bubbles and gives you a homogenous mixture. If you are casting large volumes this can be a bit tricky, but a vacuum tank will work better than adding air to the system. Still pressure, however, it is the absence of air that creates the most ideal result.
Totally think of some vacuum generator, I've seen some videos and it does wonders! But it takes a while until all bubbles you pulled out of resin disappear.
that was a job for a metalworker, you still did great with the tools you got at hand.
I always thought you needed a vacuum pot for resin casting. Thanks Frank!
Now that you have the tank, pull a vacuum on the resin before pouring. Vacuum again after pouring to remove larger bubbles. Then pressurize to reduce small bubbles.
Hey Frank, love your show. Next time just use a $5 Walmart butane torch to pop the bubbles on the surface. Works well for you, I'd hope. Take care and keep up the great work.
Thanks for sharing all the problems. Please follow up with a video of you actually using the pot for a project. Great video, very nicely done as always.
Great video as always Frank, the rubber seal ring is called an 'o' ring, they are readily available online :)
Oh, the other benefit of pressure casting with wood is that it pushes the resin into the wood.
you should try getting a 1/2" or 3/4" thick piece of plexi or lexan and cutting it the same size as the aluminum plates. try putting 1 piece in the bottom, siliconed and gasketed on the inside. i think the pressure pushing up on the plexi would seal it it to the bottom of the lid. you wouldn't have to drill a hole in it or do a top piece. it would be really cool to have a window looking in so that you can include some internal footage in future videos!
Great work!