Although many, many people are successful with them, plastic lids, even good ones on vacuum chambers still scare me to death. All plastics are not the same!
My first vacuum chamber was a stainless steel pot with a Plexiglass (acrylic) lid. There was a hole drilled through it for the plumbing to go through (supply/exhaust, gauge, etc.). On about the second use the lid imploded. In addition to making an awful "Bang!", It knocked my pump off the table and sprayed Cactus Juice around in the shop.
For version 2.0, I replaced it with a plastic Lexan (polycarbonate) lid. It was still plastic and it still had a hole drilled through it for plumbing, but Lexan it is much tougher and a lot less brittle so it can bend more without cracking. I re-used the red silicone gasket. After a few uses though it looked like the inside surface was getting some kind of little surface imperfections, surface cracks or crazing or something. That was enough to make me opt for lid version 3.0.
For version 3.0, I bought a tempered glass lid and drilled the plumbing hole near the top of the stainless steel pot. I still used the same silicone gasket.
After the whole experience, I'm still nervous when I use the thing, but at least I can be in the same room with it when it is running. I also wasted a lot of time and effort buying a thick sheet of Lexan and cutting it to size for 2.0. I wish I would have saved myself the money and grief and just bought the round tempered glass to start with. This is why I highly recommend replacing it with a glass lid.
Regards,
Dave
Original - Imploded Plexiglass Lid
Version 3.0 Glass Lid with plumbing mounted through the pot.
