I built a vacumn caster from a section of 10 " diameter pvc
pipe & 7" steel pipe. I use the pvc chamber for vacumning the
investment & the steel for casting. A 1/2 thick piece of lucite
seals the pvc & a piece of corian, with a silicone filled
groove, supports the perforated steel tubing flasks. The flasks
were homebrewed also.
Homebrewing tools is almost as much fun as using them! Cheaper
too!
Good luck,
Dave