Can I Use Vacuum Instead of A Pressure Pot to Cast Resins With?
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- Опубликовано: 16 окт 2024
- I've gotten lots of viewer questions lately asking if you can use a vacuum chamber instead of a pressure pot to cast resins with, and frankly I didn't have a very good answer! So, I called up Alumilite to get an informed answer and thought I'd share my findings.
Big thank you to Carol at Alumilite for taking the time to help me out!
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Thanks for the video and taking the time to explain this.
Someone asked about making a DIY pressure pot and here's what I did: Because I have molds that are weird shapes and sizes, I went to my local Plastics vendor (actually 2 different places) and got mis-cuts for 20 cents on the dollar, including a sheet of clear acrylic, that would end up being a viewing window (because we all like to watch). The rectangular box I made is 4 feet long, 27 inches tall and 12 inches deep, with one side being clear, and it cost $80 not including gauges and fixtures. Gasket material and cam dogs (latches) are readily available. I waxed the bottom with mold release to be able to clean up overflow occasionally and I respray mold release now an then. Have fun!
Thank you very much for the video! There is a lot of confusion about this subject. My take on it and the science of it from what I have gathered is it would be best to use both. Any object submersed in a liquid that could possibly have air in it putting it in a vacuum would pull the air out of the object and then immediately release the negative pressure or vacuum and the liquid or resin would be sucked into any crevice which is what stabilizes the wood. That process would be immediate. Create a vacuum and then immediately release it. Then put it in a pressure pot to shrink the air that has been actually removed from the object which is normally an hour case a piece of wood. I saw the experiment actually used on marinating meat. LOL. The science makes sense
I bought some clear resin to cost the inside of some cups I turned, and wound up with a lot of air bubbles. So the pressure pot is the way to go using clear resin. The type of resin I had is the stuff that you place on a table top to make it real shiny, almost like glass
Some of the early casters and stabilizers used a pressure pot that was configured to do both vac and pressure. Some will argue that vac in pressure vessel is a bad idea and I'm not going to debate it, but this was common practice 10 years ago and I never heard of any problems. The down side to stabilizing with vac using a pressure pot is that you can't see the bubbles to know that the process is complete. The up side is you can release the vac and go directly to pressure to force the resin deeper, but again the benefits of this are debatable. Is it as efficient? debateable, but it is cheaper since you are only buying one vessel (you still need both the compressor and vac pump though)
Michael T Shue Studios Thanks for the info Michael, very interesting. Sounds like a pretty cool set up having both in one, but I definitely don't like the lack of visibility when it's being used for vacuum. I also don't think there is any reason to use vacuum when doing casting. I doubt there would be any noticeable difference in quality of the final product doing vac & pressure vs. just pressure. Probably why that method isn't being used much any more.
Nice video. Calling the company is a great idea. I tried to do a little research on pressure casting and couldn't really find the answer I was looking for.
My understanding is that the air goes into solution in the resin. So basically there are no bubbles. Think of deep ocean divers. When they go down they get nitrogen dissolved in their blood. When they rise is comes out of solution and forms bubbles, giving them the bends. No bubbles on the way down (dissolved), bubbles on the way up to surface (no longer dissolved).
If on the other hand the bubbles are just crushed to a pin point and don't go into solution, then they would still exert pressure when the resin cures. So, if they were in a small point/tip of a cast, or very near the surface I would think they could crack the resin. Maybe the force is far too small to fracture even thin areas of the resin. *shrug* If the air is in solution though, the force is distributed over the entire piece eliminating the chance of fractures.
Really, in the end it doesn't matter. It works and that is answer enough. :) I just love to figure out the science behind things.
Thanks for the video.
Thanks for the input, I like your thoughts on the science too. I originally thought (without thinking about it really) that it pushed the air out of the casting completely, but the more I thought about it that doesn't add up. I'm not entirely sure that they will reemerge if you let the pressure off too soon, but just knowing they haven't really left the casting makes me think I'm best off leaving the casting in the pot for a good long while to make sure.
If it's a issue of your resin's pot-life being too short to reach appropriate vacuum, just add in a spare empty tank under vacuum pressure with an on/off valve attached to it like used on vacuum former machines. the kind used to draw heated plastic sheets over molds. IE: halloween masks, storm trooper armor, etc, etc. Once you evacuate the air from the holding tank, then open the valve it will instantly draw a huge amount of vacuum out of your vac chamber/resin. Might be tricky workin the handle to keep the resin from overflows but worth a shot.
Nice presentation mate, very throughly covered and well put.
I don't have pressure pot yet but am planning on investing in one. What I'm starting to find works best is to degas the resin in a vacume after mixing then pour into the mold then chuck it back into the vacume. De gas for the working time of the resin, release vacume and then hit any remaining bubbles with just the tip of a propane torch. Haven't got my hands on any alumilite yet, using table top epoxy and it seems to work with this so far.
Still want a pressure pot though, just to brokearse for one right just now hahaha.
Great video Zac, you have answered a few questions I have had regarding Vacuum versus pressure. Personally I always cast my blanks around the tubes for pens. the reason for this is, when you drill the hole for the tube it almost always clouds up from the drill bit heating up the resin. I don't use pressure or vacuum because it forces the resin in to the tube. I usually warm the resin to make it a thinner viscosity and the bubbles float out. I use epoxy resin as Alumilite is not available here in the UK but epoxy never seems to be as Crystal clear as Alumilite. Thanks for posting this.
All the best
Tony
Hey Tony thanks for watching, I'm glad it was helpful.
If you're interested in trying out pressure or vacuum in the future, there are some silicone molds that you can buy that use silicone plugs that seal off the tube for tube-in casting (I'm assuming you have a homemade setup for your molds). I use them when I'm doing a tube-in casting with pressure and haven't had any issues yet. They are set up perfectly, so I use them rather than making a homemade setup for that. You could just get some of those silicone plugs and try it out with a different type of mold. I get mine at www.ptownsubbie.com/siliconemold.html
Down below in the comments, Cory mentioned using vacuum to degas the resin prior to pouring. According to what he's seen, it helps with the cloudiness in epoxy. I haven't tried that personally though since I use Alumilite. It just sets to fast to use vacuum.
If you try out some new methods, let me know. I'd love to hear what results you get.
Thanks Zac, it all makes perfect sense when you hear someone else say it. I wasn't sure if pressure made the bubbles smaller or compressed the resin and squeezed the bubbles through the resin to the edge of the blank. Now all I have to do is try to find a pot that doesn't cost $500 here.
Best Wishes Brendan.
Hi Brendan, it's too bad the pressure pots are so expensive. I'm considering trying to make one DIY with a large threaded pipe in the future. Need to research tolerances and such, but it may be something to try out. I've even seen people re-purpose air compressor tanks, but it requires a bit of welding & fabrication to get it set up with a lid and all. Glad you found the video helpful, I know I had never really thought about what's taking place in a pressure pot, and I am glad I know now.
+Zac Higgins I was watching some of your videos out of curiosity and the fact that we all do things a little different so it pays to see what someone else has to say. You pretty much nailed it, no pun intended. I often vacuum my resin before mixing and then again after mixing but before pouring and then I use pressure when casting. Taking that extra step definitely makes a difference. I am a fabricator by trade and would like to caution you to be very careful when trying to make a home made pressure pot as they can be very dangerous if they explode. They may hold the pressure initially but the metal fatigues as it flexes under pressure over time and this could be a recipe for disaster...
+sams iam Thanks for the heads up. I'm aware of the dangers of the pots, and I take every precaution I can to keep it safe.
Zac Higgins you are completely wrong with the microscopically small bubbles theory! It's laughable that you actually believed this stupidity! The answer is simply this; The extreme pressure breaks the surface tension of the bubbles, but they don't get smaller and smaller till you can't see them. The bubbles breaking causes agitation and friction = heat, and pushes the bubbles up and out of solution.
@@samsiam6174 hey.. Could you please share more on the process of using vaccum on epoxy resin before mixing and before pouring?
How long is your pot life of resin and how long do you mix and how long do you vaccum it for before mixing and after mixing before pouring. Would appreciate your help.
Thanks in advance..
Can u just use a pressure pot for both removing the bubbles from the silicone mold and the resin?
THIS!! Need some info on that one as well .__.
Chubby Bunny Ive seen 2 professional videos where they only use a pressure pot, if u use a silicone that specifies it doesn't require degassing and only produces small bubbles those can be eliminated in a pressure pot.
Hey Dave, I'm not sure which vacuum chamber you have, but with pressure it's going to want to blow the lid off whereas vacuum just wants to suck it down. Many vacuum chamber lids don't have any way to clamp the top down to the pot, so it wouldn't work. I'd be careful with your setup, make sure it can handle holding pressure before you try it.
Thanks,Zac! The question I have was about stabilizing wood with the vacuum chamber. How do you set up the material to do the stabilizing? Do you put in a piece of wood and then pour the resin over it to cover it? If so why would pressure not work to press the resin into the pores of the wood?
Jim Jakosh first you have to suck the air out, before you can push resin in
The same reason a vacuum chamber SHOULD work for casting
The vacuum would not only help provide some force to move the air, but could also help in allowing the timber to expand slightly too
I think in another video he put the timber in first
best video ever on this. completely answered my question in a way I understand and explained why vacuum and why pressure for each. thanks Zac.
Nice information. People on my channel keep asking why I am not using casting on my wood or stabilizers. So I am curious even though I understand the differences, can you just do the job with a vacuum chamber and what or how do you add the resin per say? Do you just pour it in even though the chamber might be much larger than you piece? if so how do you remove the final piece from the chamber?Thanks
You would use vacuum for the stabilizing resin only. Casting is done in a mold under pressure usually. Some of the slow setting resins don't require pressure technically, but if you embed objects it's best to cast it under pressure regardless. Check out my stabilizing wood playlist and some of the other resin casting videos, you should get a good idea of the differences between the two methods from them
Excellent video. I’m going to stay with the pressure pot. Thanks for the explanation
Glad it was helpful. Pressure is definitely my choice for casting, quick and easy =D
Great video, thanks! I bought a used cornelius beer keg and a manometer on eBay and used it for 50+ plus resin castings now and it has worked as a charm. Cost me 67 $ in total.
Perfect, just the answer I was looking for. Thank you for your time!
I have seen a short video of a guy that worked for McFarlane that learned how to cast and all that cool stuff, and after he mixed his resin and poured it into his pot, he used vacuum pressure to pull out more of the air bubbles trapped inside from mixing his mold material, and it pulled up towards the top but he only hit it for a few seconds and he did this a few times, I cant remember if he had his proof in before or added it after, then, he shot his air in to force the material around the proof
I've tried using Smooth On Urethane plastic in a vacuum chamber with interesting results. (7 minute pot time) I will vacuum the individual components, then vacuum the mix, then fill the mold in the vacuum chamber and turn it on. When you fill the mold, if you just let the vacuum go, the mixture will froth and bubble and ruin your casting.
On the other hand, if you watch your mold in the chamber and ride/release the pressure to keep the frothing and overflow to a minimum, it seems to remove the large bubbles from the inside of the material and brings the smaller bubbles to the surface of the casting. It's just like what happens when you release the pressure on rising material in the chamber to push it down and then bring the pressure back up. I can't get the pressure back all the way to 29Hg. The plastic will start to froth and overflow the mold well before that point. Ease the pressure before that happens so the mold stays full, and let the material settle completely in the mold before it sets up. This doesn't work with plastics that have a very short pot life. 3 minutes is too short. 7 minutes seems just about ideal.
Although the surface of the mold winds up less smooth [more bubbly] than before, it definitely has eliminated a number of voids and seams inside the mold that I was having problems with. I will try pressure casting when my pot arrives, but I'm worried it may not work since I am encapsulating objects with voids inside them and I don't want to force the plastic into the voids.
+StudioVoodooMusic Interesting results! Thanks for sharing that info with everyone. You might be right about the pressure pushing resin into the voids of your encapsulations, but perhaps if you only use low pressure it might help. I've never really tried it, but I crank mine up when casting wood and things so that the resin will be forced into the cracks as much as possible.
Great video, thank you.
I do use vacuum to degas polyurethane and have even had good results from degassing polyester resins. I did find I had to mix slightly less catalyst for the polyesters as the vacuum tends to heat up the mix, therefore kicking the exothermic reaction faster. In the end, I still think I need a pressure pot because I still can trap air when I pour the resin into the molds.
+cavx01 Thanks for watching! Sorry for the way late response, I didn't see this comment until now. I had a feeling it might be close using the slow set resins in vacuum, but I wasn't sure what kind of result you would really get. Thanks for letting me know about your experience.
Awesome!! Thanks Zac, you cleared up a lot of misconceptions.
I am contemplating my first resin casting project. I want to make cylindrical shapes with somewhat strategic air bubbles in it, to make a light fixture for a bathroom, when the light shines through the clear acrylic it will reflect against the bubbles and make it look like bubbles in water. How would I be able to draw out the unwanted bubbles and then ad about a dozen somewhat larger ones randomly throughout the cylinder. Could I first vacume then before it sets up use a syringe to ad bubbles from the bottom? Any thoughts?
Hi Zac-love your videos and all your great explanations. I have the exact opposite question for you-forgive me if this is a dumb ask. If I have a vacuum chamber and pressure pot-can I soak in cactus juice-under vacuum, and then take that same saturated wood, place it into a pressure pot, and maybe achieve a higher saturation of resin because the pressure would force the resin in? Or am I just un-doing my vacuum work?
Thanks for any thoughts you might have!
I had a crazy idea for ensuring you don’t get voids in the resin. The idea is to have a valve where you have the resin on the outside of the vacuum pot and the mould on the inside. After you extract the air from the mould, you open the valve to suck the resin into the mould. Once the mould is filled/overflowing, then you let air into the rest of the vacuum pot. Probably not practical since the valve would be ruined, but I’m thinking that using just a rubber tube kinked could work.
I only got a vac chamber so far will that help with resin that has working time of 45 mins?
Thanks Zac. This was very helpful. If you get the right stuff, I do think it is possible to use one pressure chamber for both vacuum and pressure. It would be a steel pot with a structural clear top. That would allow you to use the same chamber for both applications (not at the same time of course!) As long as your fittings matched both the vacuum tubing and the air hose, and your valve read both air pressure and vacuum, you should be good to go. Unless I'm missing something. Am I?
Thanks for the video. Yours are very helpful.
Dave
+Dave Dontgiveout Thanks for the kind words David, and thanks for watching! You're not missing anything, you can definitely use one thing for both if you have all the necessary parts, but it's a whole lot nicer to have them separate. Plus, I recommend using the TurnTex chambers because you can see inside the chamber from the sides. It really takes the guesswork out of stabilizing since you can tell for sure that all the air bubbles have been removed. It's a little more difficult to tell what's really going on when looking down from the top.
Thanks for the explanation Zac. It's exactly what I was looking for.
These kits seem to be a lot cheaper in the US. In the UK just the vacuum chamber without the pump is about £400 and you'd be looking at the same sort of money for a pressure pot.
Luckily your advice coupled with a few tutorials on Instructables means I only need to find a vacuum pump to start stabilising wood.
Cheers,
Ben
Glad it was helpful Ben, I know how confusing and expensive this stuff can be!
TeamWild Vacuum Chamber and Pump on this website for £410 ex VAT, So not too bad.www.easycomposites.co.uk/products/vacuum-equipment/complete-vacuum-degassing-system.aspx
When you use positive pressure, air bubbles are extruded from the medium. When using negative pressure, the low viscosity of the medium allows higher pressure bubbles to move toward lower pressure in the chamber. What method you use is based on viscosity. The implements take the same amount of time to reach positive 50 psi or negative 30 Hg.
Hi Zac
I'm starting to stabilize wood and cast some resin. As I was researching this topic I cane across your video. Very infomative, thatnks for that. I have a question: Why wouldn't be able to suck air (vacuum) out of the same paint pressure pot when I want to stabilise and then use the same pot to push pressure to cast resin???? why do i need 2 pots?
I'm starting to do my research on this, too, and I had a similar thought, initially. Visibility and timing are the only things I can think of off the top of my head that would be an easy "no" answer to using it for both. When under vac, you need to observe the resin to determine when all the air has been evacuated. If you try to pour your mold, then pull vac, you will end up with a mess as the gasses bubble and expand, so keep it in a large enough plastic mixing container at first and pour when done.
+andre Levesque It's possible to use one for both, but I prefer to use the TurnTex chambers for stabilizing wood because you can see everything that's going on in them. Even with a clear conversion lid on a regular pressure pot, you can't really see what's happening very well with the wood. It helps tremendously to see from the sides so you know when you've pulled all the air out of the wood. The other reason I prefer having separate vacuum chambers and pressure pots is I am using both at the same time.
If I understand correctly, when pressure casting you get pre-stressed cast, material properties will be different. Also if mold is soft it will get smaller when pressurized? Bubbles inside will diffuse in to the resin, but what about bubbles on the edge cast/mold?
A vacuum could work with slow setting resins (or a very powerful vacuum in a small container) like he said because when there's no air in the environment, that air is going to want to float out of the resin because it's lighter than the resin and wants to move around but how a pressure pot works is completely different.
The reason a pressure pot compresses those bubbles to a microscopic level is that they're trapped in the resin at 1 atm (14.6 psi) and when you change the air pressure on the resin to 50 - 60 psi while it's still not set that's 3 to 4x what the bubbles have in them so the molecules are naturally pushed into a smaller space and the flowing resin moves simultaneously to fill the space those molecules took up at 1atm.
Of course, if you could cast all your resin in a vacuum or hypobaric chamber, there'd be almost no air to mix into it and you'd have perfect casting without a pressure pot every time! Of course, making a personal vacuum or hypobaric chamber is probably not the best or safest route and would cost you 10s to 100s of thousands of dollars for minimum benefit.
I put the two portions in the vac and remove most of the air.. Takes a while because it is thick. Then I mix the parts together and then pressure. Word of caution, if you vac it and there are big bubbles in the parts you could have a big bubble to compress and it may not. Then you have a void in your blank.
THANK YOU.I really appreciate it when experts are prepared to share their knowledge.
Can I use my basic airbrush air compressor with a pressure pot.I am considering building one from the Harbor Freight pressure pot and convert it. I’m hoping I don’t have to invest in a gigantic air compressor. Thanks for your time.
I’d like to start casting. I’m going to use either ecopoxy or Art Resin’s new casting resin thick cast whine it comes out. I’d like to do the pressure pot thing but I don’t get how to modify a paint pot and it looks scary? How to do this in an easy peasy way?
Zac I have that same pressure pot, the first time I put air in it (30-40psi) it started to make popping and pinging sounds. Is that normal?
If I want to pull bubbles out of resin before I pour a project is a vacuum chamber the way to go?
The principle of how the pot works seems insane to me ! Thank you very much ! I have had hideous bubble problems trying to trying to create new products and transcend to more fun and cool things but I am beat right now ! I am down , but not OUT ! I AM TAKING A BREAK for a week ! Yes I bought a pressure POT ! ☀☀☀☀☀
Thank you for your video about epoxy! They are gorgeous.
Can I ask you something? Pressure chamber - what effect does it offer? except for the resin degassing? whether a resin harder (stronger) after this chamber, than before, as an example? or just degassing? I can not understand why do you use for resin vacuum chamber at first, and then give the resin to harden in the pressure chamber
Why vacuum is not enough?
Thank you.
I don't use vacuum at all. I just use pressure to shrink the air bubbles in the resin, it doesn't do anything else to the resin
I live right down the street from Alumilite and they are awesome people....
With the right resin and feeds you can cast flawless by vac. The art is in the mould making and the cut of the mould. I have vac cast for 5 years and I am fortunate that I am classed as a good product due to my casting. I do own a pressure pot and comp but until now it hasn't been needed. I cast from 54mm to 200mm full fig. My point is you can vac cast to a high standard with prep
I notice that you have the same vacuum pump that I have. Mine came with a filter on the intake side and it appears that yours does not. I'm new at this, but I assume that the filter will keep fluid/water from the pump. Have you had any issues with it? Also, what is the inches of vacuum that you obtain? I'm running about 25", thanks.
+William Pitzer I have no clue if the filter would help or if I'm missing it! LOL I haven't had any problems though. According to my gauge, it pulls right around 25. That number is dependent upon your elevation though as well as barometric pressure I believe. I'm pulling near the full vacuum I can get at my elevation...assuming the gauge is accurate.
I didn't read all the comments, but I can't help thinking that the down side to pressure curing is you are trapping high pressure bubbles inside of the resin, which I think would stress the resin more than if you sucked the air out. This is basically how they make pop rock candy, taking molten candy, whipping air into it, then putting it under great pressure, and allowing it to cool to trap the bubbles. In my younger years when I worked in the electronic industry, we would always vacuum out the bubbles in the casting resin before encapsulating the electronic components. Yes, you need a slow cure resin to do it, but we didn't need to get 100% of the bubbles out. The bubbles that were left were small, and then when the vacuum was released in the vacuum jar, those small bubbles shrunk to nothing. No trapped super pressure bubbles to contend with. But that all changes if Alumilite creates it's own outgassing bubbles as a byproduct of curing, and not just from introducing air into the medium while mixing.
I agree that it seems like that would be the case, but I don't think that's actually how it works. If that were the case, every blank I turn would blow up the instant I started cutting into it. My theory is once the bubbles are collapsed, they mostly float to the surface. Need to find a chemist/physicist who can give us the run down on what's happening exactly. For now, I'll just chalk it up to magic since it works =D
I see this pressure tank listed at Harbor Freight as a (2 1/2 Gal Air Pressure Paint Tank), How high (psi)do you cure at and what is it rated for?
Also, Will that tank hold the proper pressure for the entire time when pressurized?
I actually use C.A. Technologies pots now, they are rated at 80 PSI, and I run them no higher than 70. The Harbor Freight pot I used to use was rated at 60 max psi, I would go up to 50 in it. Just make sure you read the label on any pot you get, they will say what the max psi is, and I always stay 10 psi below whatever the max is. They will hold pressure as long as it doesn't leak. I have a video that covers finding and fixing leaks in pressure pots that might be helpful: ruclips.net/video/ZzdNZ6nqrgM/видео.html
So stabilizing wood with resin, you have to use a vacume chamber? And cant use a pressure chamber? I'm new to this and have some cool, very porous wood pieces I'd like to turn.
Best explanation of the pros and cons I’ve seen! Thanks!
The problem with a vacuum is that most resins produce gasses as they cure - thus filling your vacuum with gas and ruining its effect. Pressure pots force out gasses in the resin or nuclearize them, this increases pressure, maintains efficacy and will be taken care of by the pressure valves (or more likely compensate in some small ways for the leaks)
Can you use the same vacuum pot motor for the pressure pot ?
I wanted to start using resin in my bowl turning. It sounds to me that you said you can avoid the vacuum and go straight to the pressure pot to make the bubbles so small that you can't see them. But I didn't understand when you said you need a vacuumto stabilize wood.
Wood stabilizing and resin casting are two totally different things. Check out my Wood Stabilizing videos to get an idea of how that works, it's more for hardening up soft/punky wood. You replace air inside the cellular structure with stabilizing resin and bake harden it. Think resin impregnating. Resin casting is like making acrylic blanks, casting resins will fill voids but doesn't penetrate the wood fibers like stabilizing resin would
Just to clarify a bit technically the best way is a vacuum, that will give you the best product with the most solidity and structure but is not practical bc it pulls the bubbles out and in doing so causes a boiling and over flow which will leave you with half your resin in your mold and the other half around it and in the bottom of your chamber. While pressure puts pressure on the outside of the bubble making it much smaller but the bubble is still there just so small you can't see it all that well this, this leaves a clear products that is almost as clear as a vacuum, doesn't make a mess and doesn't waste resin. So yeah pressure is much better and easier especially if you don't need structural strength. This is why carbon fiber is done in a vacuum and not under pressure bc it's way stronger
Looks like it's gonna be a pressure pot for me! Thanks!
Can pressure pots be used as a vacuum chamber as well?
Zac, it seems to me that a pressure pot could also be used as a vacuum chamber the only problem may be that you can't see through the lid unless you make a clear lid, do you see any reason why this wouldn't work?
Thanks
You could, but you really need to see inside when you are using it for vacuum or the contents can overflow out of the mold. They make clear conversion lids for them though, I have one that I use for degassing silicone
Thanks bud.....been looking and I have a vac chuck system and all the pressure I could use.......building blocks
Hey Zac, this makes me wonder if vacuum will create a more structurally strong end result... just thinking out loud
Thanks for the content!
Hey William, very valid question. I am still trying to get to the bottom of exactly what is happening to the bubbles under pressure. The best explanation I've heard is that the air bubbles go into solution with the resin once it turns from liquid to solid effectively removing them from the equation. So I don't think there is any drawback to the resin in terms of strength using pressure. Vacuum just takes too long for most resins, and it also has different effects on certain chemicals which can cause more problems that it's worth. Peter Brown just did a video on it a couple weeks ago with the same results and conclusions about it. Just don't think it's the best option when it comes to resin casting, but it definitely has it's uses for silicone or stabilizing
Zac Higgins Thank for the reply and the content!
I casted a two pen blank mold last night for about four hours. After the first thirty minutes I noticed that the pressure had dropped from 45 psi to 30 psi. I added more air and it did it again so I added more air. After the third time I added air and left it alone. After I finally released the pressure I could see some air bubbles on and near the surface of the blanks. What should I expect to happen when I turn the blanks? Can the holes be filled with CA glue before sanding?
Hey Keith, first off I would recommend watching my video on finding and fixing leaks in pressure pots so you don't run into that problem: ruclips.net/video/ZzdNZ6nqrgM/видео.html
You should be ok if there are a just few some small pinholes, you can fill with them CA. If the blank is riddled with holes, it could be a little chippy, but you should be able to get through turning without problems. You might want to pull out the face mask out just to be safe
Zac I have just bought a pressure pot and the set is : one outlet for the pressure gauge and one outlet for the paint collection: My question is do I seal the one pipe that goes to the bottom.? Or what goes where??? PLEASE HELP
Hey Geoff, probably easiest to direct you to my videos that cover setting up a pressure pot. I have one for C.A. Technologies pots (ruclips.net/video/6iQEPaa82Z0/видео.html) and one for Harbor Freight pots (ruclips.net/video/vO1sD3rvZdA/видео.html). Should help you figure out which parts you need and where they go. Make sure to check out my video on finding and fixing leaks before you begin, I have a tip on what type of thread sealer to use, and I'd recommend using it off the bat to help ensure the fittings don't have any leaks: ruclips.net/video/ZzdNZ6nqrgM/видео.html
So how long do you wait for it to cure?
A vacuum chamber is also known as a degassing chamber. When you use silicon and slow setting resins (not alumilite) for molds and parts engineering you want to "degas" the silicon before you pour it into a mold so you get a pure cast. Depending on the set time of alumilite you could theoretically degas it before poring it as long as you can accomplish it before it's set time. I assume they (alumilite) recommend the pressure pot because the set time is too fast for degassing. Sounds good in my head anyways lol
Thanks for mentioning silicone molds, they definitely can use degassing if you want to make good quality molds. As far as resins go, as long as you don't shake up the bottle of part A and part B, there shouldn't be any air in the resins before you start mixing anyway. I may be missing something though. Alumilite would cure too fast to cast it in a vacuum chamber, but it may be possible with PR or epoxy.
I've never tried it personally but I've seen it, if you mixed two batches of clear epoxy one just trying to mix it without causing too much air to get in and the other put through a vacuum chamber the degassed batch will come out super clear while the other will be kinda cloudy. think it was west epoxy they used.
Cory Tichenor Interesting, might have to try that out one of these days.
I found that when de-gassing polyester casting resin, it gasses indefinitely. I suspect that the resin creates gas during the reaction but not enough to create bubbles in normal sea-level pressure but it's noticeable in a lower pressure. So I cannot see how anyone can leave a cast to set in a vaccum pot.
I think the issue with vac instead of pressure is that vacuum reduces the boiling points of the compounds that make up the resin so it will likely froth as it releases all of them gasses, with pressure it pushes all of the air out of the resin without lowering the boiling points (it increases boiling points with pressure). Disclaimer: I've never actually done a vac on resin but just my thinking with my experience in organic chemistry 👍
I think that using a vacuum when casting wood and resin together is likely to make the problem worse by drawing air out of the wood and creating more bubbles. Cheers, Jim
Yeah, you nailed it. That's exactly what happened when Dema tried it in his video with Alumilite Clear. Foamed up like crazy
Agree, but you can vacuum only resin and then poor it on the wood. Maybe that way it will be better solution for removing bubbles with just vacuum chamber?
Awesome video. Thanks for sharing. Tells me a ton being a newbie just getting into casting resin.
That's awesome you're getting started, it's a blast!! Glad the video was helpful too, I know there's a lot to take in when you're just getting started
Zac Higgins can u please explain the plumbing - like parts I'd need and what connects to what. I'd like to go today and purchase them to assemble my chamber this weekend.
do you have a recommendation of the best pressure cooker to use when starting up im doing resin casting of small models and want to find a cost effective way
You don't want to use a pressure cooker, you want to use a converted paint pot. I personally use C.A. Technologies brand pots, they aren't cheap but they're excellent quality. I think the cheapest way to go is the Harbor Freight pots, they're around $90 plus parts to convert them. I have videos that cover converting them and tips to get them sealed up. There are videos that cover both brands and a feature comparison between the two: ruclips.net/p/PLoeB-EPC_91uBZHKS1mbeoy9AZyjjZmrA
What pump do you recommend?
very helpfull video!!.... can i use any kind of compressor with the pressure pot? like the compressor i use for my airbrush?? thanks!
I'm glad it was helpful Pedro =) If it's a tankless airbrush compressor I don't think it will work too well. If it can push enough cfm's though, it might work. I think the pancake compressors are about the smallest compressor I've seen people use without any problems
So... my paasche D3000R compressor with 1gallon tank will work?? Do you sell pressure pots for casting? Thanks!!
I'm not familiar with that one, but it might work. Usually best to have a tank that's similar in size to the pot, but as long as it has the horse power and can provide the cfm's, it should work. Always worth a try. I don't sell any equipment myself, just pen blanks. I purchased my CA Technologies pots at Finish Systems online, they have some that are set up for resin casting: www.finishsystems.com/resincastingpressurepots.html
you rules Zac thanks!
Happy to help :D
Vacuum can/will make volatile compounds in the resin gas out so you may need to be a bit careful about which resins to use in vacuum.
Thanks for mentioning that. I wasn't aware of it when I made this video, but I found out the hard way during a test I did with epoxy under vacuum since I posted this one. Pressure is definitely the way to go for casting resins, vacuum just causes problems with most resins and takes forever even if it doesn't boil it or cause the resin to expand out of the mold
@@ZacHiggins the ideal would be a short vac to release trapped bubbles and spraying top of resin with a bubble burster will help.
This avoids removing any volatiles. Then pressure can be used to suppress any remaining microbubbles.
Sorry to ask nut I am new to all of this. Where do I get a pressure pot at the cost you mentioned?
Harbor Freight has cheap ones, I'd recommend going with a CA Technologies pot though, far better quality. I have links to the CA Technologies ones and lots of other casting and turning tools and supplies on my website: nvwoodwerks.com/tools/
Thank you sir I will check it out
Hi Zac the ones from CA do you have to purchase all of the fittings separately?
Yes, you will still need the ball valve, elbow and male air hose connector for the 'in' side of the regulator and a cap for the 'out' side, all 1/4" fittings
thank you sir I really appreciate the information I literally just saw the video between the Harbor Freight and CA Technologies pot I appreciate all that you have discussed with all of us Anna videos you post are very helpful thank you for taking the time to do this
That was a question I've had rolling around my head for a while. Thanks for the answer Zac. -Chris.
Me too! I really had no clue how it worked, just that it did! Glad I could pass it on.
whats the minimum pressure that has to be used to get a good cast in a pressure pot?
Well, that depends on how big the air bubbles are. The higher the pressure, the smaller they get. I think Alumilite recommends over 40 for their products, I usually run my CA Technologies pots at 65-70
thanks for the quick reply!
unfortunately a proper pressure pot costs around 400euro where i live so im trying to make a homemade one out of a steel cooking pot
I have a few molds and wanted to know how i would keep them from deforming my castings or the mold it's self with 60 psi becouse if you couldn't tell, thats a lot of pressure(thank you for reading the coments)
Side question. Dose it only work for reson?
What is the difference with Cactus juice from Amazon, and Medium volume and High volume
Very helpful tutorial! Thanks for sharing this information.
My pleasure John, I'm glad it was helpful =D
couldn't you use the the pressure pot as vaccum container just by switching between vaccum pump and air compressor with quick connect fitting? It seem people like the clear vaccum so you can see the bubbles escaping the wood.
Yes it's possible, but if you can't see in the chamber you don't really know when it's done. Bare minimum you want a clear lid. I actually prefer a totally clear chamber made out of clear PVC pipe
Do you have a diy pressure pot video?
To stabilize the wood just drop it in Pentacryl. That's supposed to flush out the water and replace it with Pentacryl. No resin needed. Then cast the wood if that's what you want to do. Montana Wood Art.
Thank you Zac, you giant angel you (maybe I’m wrong but you look pretty tall, 6’3 maybe taller). I’ve been so stumped as to why this works.
You're welcome Alexia I am 6'3 by the way good eye =D
Thanks so much for this video Zac. Supper helpful!!!
Glad it helped out Mitch =D
Can I use the pressure pot with an acrylic lid as a vacuum chamber?trying to minimize space and cost. Just not sure if the pressure pot can handle the vacuum
Hey Greg, yeah it's possible to use an acrylic lid to convert your pressure pot to vacuum. Just make sure it's thick enough to handle the stress of being subjected to vacuum, too thin and it can crack or possibly shatter. There are companies out there that sell lids for that purpose, or you could make your own. Unfortunately I don't have any expertise in that area, so I couldn't tell you what the minimum specs would have to be for it. Just know that if it's too thin you could run into problems
Zac Higgins thanks for the info. Been doing research. 5/8 is thick enough but have been reading that cactus juice Will ruin plastic lids. Says I should use glass vac for stabilizing wood. Any input on acrylic lid? Thanks in advance.
Cactus Juice doesn't hurt plastics, my entire chamber is plastic. The lids crack because the material is too thin or improperly machined for the fittings. I'd contact Curtis Seebeck directly to get the scoop on it, I'd imagine he can tell you what the minimum thickness required is too www.turntex.com
Zac Higgins you have been a wealth of information. Thank you!
My pleasure =D I know it can be tough sifting through all the info out there
Thank You Zac. For doing this Video! have been getting beatup over this issue!
+Carl Smith Definitely! Sorry I never was able to do the side by side test though. To be honest, I just felt like it was a waste of time and resin to actually test it. Dema also did a video on this, and actually put Alumilite in a vac chamber. Results were horrible LOL. I'm pretty satisfied that pressure is the best way to go for casting, vacuum is good for silicone molds.
can you suggest a good entry level pressure pot?
Hey Jim, I recommend going with the C.A. Technologies pots. It's a little more expensive than the cheap ones, but they are far better quality, safer, and you can go to a higher PSI with them. Most of the cheap brands will not stand behind the max psi rating they show on the pot if you call and ask about it (assuming you can even call and talk to someone about it), which worries me.
C.A. Technologies knows that their pots are being used for resin casting at higher pressures, and they have absolutely no problem with it. They even introduced a model made for resin casting that is easier to set up for casting. I have a "tools I use" page on my website with links to the ones I buy that are set up for resin casting: nvwoodwerks.com/tools/
With the safety aspect involved, as well as the night and day difference in quality, I just can't recommend one of the cheap pots in good conscience.
Thank you for responding. I ended up buying a 5 gallon pot from California air tools for $207 and some change. It is rated up to 80psi and has the big latches like the one you have. much better than Harbor Freight. It did take a little bit of modification to get it ready to use, but not to much.
Here is the model that I got. California Air Tools 365B 5-Gallon Pressure Pot
Before you use it, I'd recommend contacting the manufacturer to see what psi they recommend using it at and what you plan to use it for. I tried saving a couple bucks once on a pot that looked pretty similar to C.A. Technologies, and the company told me they wouldn't recommend going over 35 psi in it even though they advertise a max of 90. I'm not saying it's a bad pot, but cheaper price tag typically means cheaper materials or less quality control. Better to be safe than sorry
Thanks Zac.
I had just gone to your website and asked this question. Then began to wonder about your RUclips channel to find the answer and there it was. I am a subscriber so I don't know how I missed it when you posted it.
Anyway. Thanks for the clarification. JimE
Just sent you an email, then I saw your comment here. Between the video and the email, I'm hoping they cleared things up. Don't hesitate to send me a message if you have any other questions though.
Zac Higgins Thank you. The email must have gotten eaten by the internet aliens. It never came through. Such is life. JimE
blackemmons Holy cow, thank you for letting me know that you didn't get my email. I went back to see what happened, and I realized that I have been sending response emails to myself instead of the person who sent me the email on accident!!! I've been doing it for months now without even knowing. I feel horrible, but at least I know now and was able to get in touch with everyone that had emailed me. Thank you again for letting me know!
Zac Higgins Zac, Now that is funny. If you don't get enough emails and have to write to yourself, let me know. I'll write you more often. :-) JimE
blackemmons Haha!!
Buenas tardes No hablo inglés pero soy de Costa Rica y me gustan sus videos Me gustaría me explique Cuándo se utiliza bomba de vacío y cuando se utiliza presión para Cuál de los dos tipos de procesos
Thanks Zac! That was really nice and informative. :)
Was hoping you would do examples.
can i use a vacuum chamber to day plywood
Iv tired it with small blanks and it just creates a mess because it's pulling air from the wood threw the epoxy. But I do mix epoxy and put it in the chamber to pull the air bubbles out for pouring on larger projects.
Too many variables in the questions/offerings here. 1) A series of brief vacuum/lower pressure over just the solutions expands dissolved gas, letting it rise and escape before pouring, as long as the cure time is slow enough; 2) A vacuum over wood blanks does the same but the wood density means trapped air can take hours to be slowly pulled; 3) Releasing vacuum means a return to ambient pressure, forcing whatever liquid the part is submerged in to penetrate where trapped air was pulled from. 4) Adding more pressure only serves to speed up the rate the liquid can penetrate, and will compress any remaining bubbles but only if the solution reaches those areas. 5) This slow process precludes most catalyzed resins, as they harden long before deep penetration occurs; 6) hence, the value and practical advantage of Cactus Juice type liquids, which stay thin until baked. For wood stabilizing, pressure is less valuable than slow long vacuum, because pressure benefits more crystal clear castings where bubbles are undesirable, but pressure alone will not force resins deep into dense material like wood where trapped air pockets will just shrink but not vanish.
I think you might have misunderstood the topic. This video is focused on casting resins, it is not at all about stabilizing wood. The intention is to remove air bubbles from casting resins only
Thanks for the video. It's quite educating. When I cast the resin I try to use vacuum chamber, and the resin began like to 'boiling' out of silicone mold. Then I decided to degas mixture of two components itself, couse the bubbles, as i read on one forum, is a normal chemical reaction while the two components comes into mixture. So after the bubbles went out from the surface I fill the mold with degassed resin and put it into pressure pod for some period. I wait a result minute from minute...
But do you use a different compressor?
You use a vaccum pump to pull vacuum, air compressor to pressurize the pressure pot
Hey Zac, great info brother!
Thank you for the very informative video!! :)
I have thought about this for years!! thanks for your thoughts to understand :)
Sophie Nelson I know how you feel Sophie! I kept hearing conflicting answers to that question, depending on who you ask. So, I decided to do some investigating!
I still think I'm going to do some experiments with it using PR and epoxy in the future though. I need to convert a pressure pot into a vacuum chamber first. I think it could be "possible" to use vacuum, but I'm pretty convinced that pressure is a better choice regardless of resin. I'm 100% convinced that you should NOT use vacuum with Alumilite since it sets so fast though.
+Zac Higgins It may be beneficial to vacuum your 2 parts before mixing to degas any bubbles entrapped when pouring out of the original container. Just a thought; when carefully mixing so as to not trap air in the mix, it takes additional time. Is it the same amount of time or close if you would just mix quickly, degas and then pour? I would think it is comparable. Alumalite is pretty fast setting, it may pay to use one of their slower acting compounds. Have you ever tried Silmar products? They make some top notch products as well but then again, I am using polyester.
+sams iam I find pressure to work just fine for this application, and it's really the only option with Alumilite due to the fast set time. I have tried PR, but I can't stand the smell of it and it's brittle. Alumilite is a much nicer product to machine/turn, and I prefer the fast cure time as well.
You know, with the stuff right there in front of you, I was fully expecting a more scientific method. I.e. just straight up try it with both
Yeah i was waiting for hom to do some demos
Same
Over 2mins of utter waffle before you said anything.
How's your rubik cube puzzles going
so it wasn't just me
***** From what I've heard, the amount of pressure needed to stabilize wood with pressure requires a pretty super-industrial setup that is literally not possible to do in a home workshop.
Could you elaborate on the stabilize wood method you're referring to?
Dyami Plotke I wasn't sure which method you were asking about, so I covered both...
If you're talking about using pressure to stabilize wood, you put it under extreme pressure and it forces resin into the wood. I don't really know anything about that method, but from what I understand it takes way more pressure than you can get with an air compressor.
The vacuum method is where you suck all the air out of the wood in a vacuum chamber. Once all the air is removed and you release the vacuum, resin is forced into the interior of the wood where the air was. You then bake the wood which cures the resin inside the wood.
I have a video series about using vacuum for stabilizing wood if anyone is interested in seeing that method ruclips.net/p/PLoeB-EPC_91vC03jk5hS8SH_7Ow4nqyZL
Thanks, Zac Higgins I'll definitely take a look.
Thanks for the knowledge
Thank you for sharing.
Silicone molds it works great!!!
You have to use a vacuum system when you want to treat wood.
If you dive 50 to 60 feet (20 meters) a balloon fist size will be flattened. The air is compressed by 2 atmospheres (as in the pressure pot at 50psi) . That is how I think of it.
i want to make some pen blanks and wine stopper blanks with sea shells. So if I understand this correctly I need a pressure tank
I'd recommend it for best results. It's not entirely necessary if you are using a slow setting resin, but Alumilite Clear definitely needs to be pressurized to get the bubbles out. Even with slow setting resins, the pressure will help a ton when you embed things in it. If the air bubble is trapped under shells, it won't wiggle free on it's own, so the pressure will help out with the stuck ones