Homemade Vacuum Chamber

[whytwolf]

All,

I know I've seen one posted on these forums before, but the search isn't finding it for me. I'm looking at trying to put together a homemade one with some PVC pipe fittings and my Dustbuster, and was hoping I could get some advice.

Was also wondering about how long the vacuum needs to be on--only untill the mold/resin is de-gassed right, not for the entire cure time?

Thanks for the help.

Sean

[cobywan]

I made mine from sheet styrene rolled into a tube and glued the livinv p!$$ out of it. I glued the tube to a plate and made a lid out of 1/2" polycarbonate sheet. I waxed the lid with Johnsons Paste Wax and gooped silicone caulking onto the lip of the tube and pressed the lid onto it. (Let it dry for a couple of days or more. And don't lift it untill it's dry or you will make the seal not work.)

I Bored a hole into the lid to accept a hose connected to a venturi pump that I bought from Harbor Frieght for $14. A vaccuum guage would be nice if you can find one.

I can't recommend vaccum casting resins if you don't have a pressure chamber. The vaccuum makes the resin boil it's stinky components and they don't dissolve back unless you pressurize them. But for the rubber you just need to evacuate the chamber long enough for the bubbles to go away.

[Myersjessee]

I bought a nice small plastic one. It was like $75 and is rated up to 29". Not as cheap as coby's, but reasonable in the scheme of things.

[whytwolf]

Thanks for the info guys. For the second question--does the vacuum or pressure need to be on for the entire cure time, or just until the rubber de-gasses?

Sean

[Myersjessee]

just until it degasses is what I do....then I stick the vacuum hose to my head and make hickey marks...

Edited December 3, 2004 by Myersjessee

[fulcy]

I got a 12" diameter, 3/8" thick wall PVC tube - it was scrap from a job at work - and glued it to a 1/2" thick plate for the bottom, and made a nice top out of a 1/2" sheet of clear acrylic. Work great down to whatever vacuum I want to throw at it - and only apply vacuum to your resin to degas it until it's done boiling over. Don't let it cure under vacuum - I can only assume you'll get large airbubbles, and nasty results. However, I do cure my casts in a pressure chamber - I bought a pressure paint pot from sears for about $100, and after I degas my mold full of resin, I throw the whole thing in the pressure pot at about 50 psi for about 4 hours (depends on the resin being used - until it's cured). Works like a charm, and I hardly ever get air bubbles (as an example, I've probably cast 30 sets of head lasers, and only one of them had a tiny air bubble - all the rest were perfect! ).

[whytwolf]

I got a 12" diameter, 3/8" thick wall PVC tube - it was scrap from a job at work - and glued it to a 1/2" thick plate for the bottom, and made a nice top out of a 1/2" sheet of clear acrylic.  Work great down to whatever vacuum I want to throw at it - and only apply vacuum to your resin to degas it until it's done boiling over.  Don't let it cure under vacuum - I can only assume you'll get large airbubbles, and nasty results.  However, I do cure my casts in a pressure chamber - I bought a pressure paint pot from sears for about $100, and after I degas my mold full of resin, I throw the whole thing in the pressure pot at about 50 psi for about 4 hours (depends on the resin being used - until it's cured).  Works like a charm, and I hardly ever get air bubbles (as an example, I've probably cast 30 sets of head lasers, and only one of them had a tiny air bubble - all the rest were perfect! ).

Sounds cool. Did you have to modify the pressure pot any? Did it come with a compressor, and if not, what do you use for it?

Thanks again guys, great ideas!

Jesse: I don't think I've gotten a hickey in any way since highschool, but now that I'm divoced, you've giving me some ideas

Sean

[agass4u]

One suggestion I have seen was on the Child Of Mecha website under the basic resin casting tutorial. He uses a Food Saver vacuum container. I am not sure how much they run, but I think it would probably a lot easier than trying to may your own.

Here is the website, look under the modeling link and then basic resin casting. Hope this helps.

Child of Mecha

[whytwolf]

Hrmm, that's a neat idea....although the FoodSaver appliances are just outside of my price range, thus my need to go with a cheaper solution

Sean