On 3 Dec 2005 18:53:05 -0800, "bschwand"
wrote:

I want to build a device similar in some ways to a vacuum chamber.

So use a vacuum chamber. The scrap trade for lab scrap is a bit
obscure, but it is out there. S/H vacuum systems are there to be found
and I've always bought them for no more than scrap steel price. Pumps
OTOH are expensive, because there's a good market for those. The
_convenience_ of well-designed well-made vacuum plumbing is worth the
effort of searching for it.