I recently tried to make my own vacuum chamber using a 2 -stage 3
cfm 25 micron vacuum pump. The base of where my bell jar is sitting
on is wood covered with a silicone sheet.
The wood base reminds me of jokes about screen doors on submarines
Aluminium, plexy or even glued formica would really help for the
base. Your pump sounds good, vac work really takes care of all the
little details. At the best of times it sucks big time
Analog/Digital Modelling & Goldsmithing