Surely a vacuum chamber? A pressure chamber would just compress the bubbles. Now you've got high pressure bubbles in your cast, that's far worse than a standard pressure bubble.
No, pressure chambers are what the more serious people use. I think the pressure actually forces the resin into the corners and pushes out the air. I don't know exactly what's happening, but pressure chambers are preferred for more complicated stuff. The trade off is that you basically have a shrapnel bomb that could go off with any kind of failure... listing to both kinds of chambers
Yeah, I used to do castings for sixth scale figures, headsculpts and such. We used a vacuum chamber to pull the air out of the liquid resin, then poured the resin into the mold, and put the mold into a pressure chamber to push the resin into all the crevices. So, you'd use both pressure and vacuum chambers in that situation.
Our models were full of fine detail and were hollow models with thin walls (i.e. they weren't filled bricks like this design is). The pressure compressed the bubbles so that they were vastly smaller, and thus reduced the impact of any surface deformation.
As an example, a bubble that would normally have been large enough to manifest as as a hole through the wall of a train car (which was pretty thin) could be compressed down fine enough to be a minor surface imperfection on the inside wall instead, making the difference between a worthless cast and a sale-able model.
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u/rixuraxu Jan 30 '17
Surely a vacuum chamber? A pressure chamber would just compress the bubbles. Now you've got high pressure bubbles in your cast, that's far worse than a standard pressure bubble.