Does anyone have any interest in building a vacuum chamber for degassing resin castings?
I am curious about drying wood in a vacuum chamber. Also in the use of them in freeze drying… you are probably thinking smaller, though
Why not pick up an inexpensive old pressure cooker and use that? Should be strong enough to hold a hard vac.
HIVE13 has several vacuum pumps that will pull a pretty hard vacuum. (Vacuum former)
Something like an old weber kettle grille that you could seal up with silastic for a gasket.or the aforementioned pressure cooker would make a decent chamber. The seal on the pressure cooker was designed with a gasket that blows out against a rim to hold pressure in not the reverse. Watch for one with an inner lip to bear against the gasket.
As to wood,of length, one could make a chamber out of large diameter PVC pipe. It could hold something long.
The pressure cooker I have at home would probably actually work… I never even thought about it…
You can buy a good vaccuum chamber for fairly low cost, I have one for my silicone and casting resin. I have seen some made, but the safety aspect for a tool like this, I recommend just buying one.
While we are at it I would recommend a pressure pot, if we are looking at a resin casting tool, I recommend: dedicated level work surface & pressure pot.
Any interest in a 55gal steel drum? It’s a little on the large side but designed to be vapor sealed
that amount of vacuum or pressure needed for that would require a huge compressor or vacuum pump to be reasonable on its speed. For vacuum degassing and pressure casting time is a concern as you are fighting the potlife.
I can get loads of 5gal fuel drums too that are metal and vapor-sealed. If you want em, lmk.
Thats the size that would be reasonable for this. Can you send photos? the issue with these are mostly if they can handle being under a vacuum. (I dont recommend anything but a pressure pot for the pressure casting, for safety reasons)
They’re comparable in construction to a 55gal drum but smaller.
it may work, but honestly I am not sure. I dont think many of the drums are made to handle a vacuum but I would have to test it. I can bring my Vacuum pump and lid (if it fits and test it, but there is a risk of collapsing the drum and making it unusable for anything.
Do you know what kind of kpa you draw down to?
between 85 and 100 on average.
The ones I am using at work use a thick piece of acrylic to watch the plastic while degassing. Said cover is covered in clear tape too, for splashies. A bit of finesse with the lever, if it starts to boil over, and a bit of care not to let the inrush tip the resin over when venting to open. Most times, the bubbles “fall” at about 25 inches Hg. And yes, pot time is a right pain in the you know what, almost worth thinking about a chiller for some pours.
Hive owns this vacuum pump.
It pulls 5 cfm and is rated to 35 micron.
A 55 gallon drum is a little over 7 cuft
25 inches of water is a little less than 100,000.00 microns
That pump should evacuate a 55 gallon drum in minutes.
As to chilling the pot. Use ice. Water doesn’t boil at chilled temperatures until the vacuum is harder than 29 inches of Mercury
minutes to pull 29in of mercury is too long when talking about resins with a short pot life.
I think 5 gallon chamber is plenty for anything I would consider… 55 gallons chamber would be for parts way bigger than I would consider shelling out the money for that much resin…
Silicone baking mats work well to seal the rims of vac chambers.