I work with some samples that are dissolved in ethanol. Currently, we plate them, and evaporate overnight in a fume hood, and then bake them using a standard convection lab oven. It takes about 24 hours and really slows me down. And buying an explosion proof vacuum oven is ridiculously expensive. I've been quoted $40-50,000 for "table top" units. So, I figure, I'm a mechanical engineer... I could just build me one. But I've never designed a vacuum chamber. How do I go about it? I know the myth of "just build it thicker" is a bad. Ideally, what I'd like is a square box, with 4 walls, and a bottom that's 12" x 12" x 12". The top would be a 14" square, with a gasket that could be laid on top of the box, closing it. and I've had 2 ports on the side of the box, one for a vacuum break valve, and another for the vacuum line to hook up to. My vacuum pump is a 3-4 CFM air operated vacuum pump. It's capable of 25" of Hg vacuum. I can externally heat the box with an intrinsically safe hot plate, or steam source. I'd appreciate some help, or a lot of help, with attacking this project. Thanks everyone.