Review on 🔬 BACOENG Stainless Chamber with Silicone Degassing by Issac Smart

I bought this chamber to use for freeze drying which requires a vacuum of around 200 microns. Unfortunately, there are a few unfortunate design decisions that prevent this chamber from reaching this pressure. First, the chamber uses a bulkhead fitting that goes through a hole in the side of the chamber. The bulkhead choke is flat and the chamber wall is curved, so a rubber washer and compression are used to seal the connection. Despite my best efforts, I was never able to close it well enough to prevent a tiny amount of air from escaping. The best I could do was about 2000 microns (about 0.3% atmospheric pressure), which is about 10 times what I need. The second problem is that the fittings and hoses used are very small in diameter. The hose may have a 1/4" fitting, but the actual inside diameter is less than 1/8". When operating the vacuum pump at very low pressure, the tubing diameter should be as large as possible to maintain a good flow rate. I think this chamber is well suited for applications like degassing that require a moderate vacuum. I've seen questions from other potential buyers to which BACOENG replied that their cameras can go down to 25 microns. I suspect cameras with top ports (through a flat acrylic cover) can probably be that low, but not this design. It's either that or I have a faulty faucet. One last thing: the glass lid is very heavy and strong (which is a plus), but the walls of the chamber are actually quite thin, and when the chamber is evacuated or vented, the metal base creates a very loud bang as atmospheric pressure causes it it sags slightly inward. It's a little mind boggling and I wish they'd made it a little thicker to prevent that.