I wish to design a two chamber stainless steel vacuum system where the two vacuum chambers are connected via a flexible tube with a valve. The system needs to be able to be pumped down to 6 torr and must be able to maintain that vacuum for at least a year without pumping. The size of the chambers are 2" x 4" x X 12" X 0.12" (Height, Width, Length, Wall Thickness) and 6" x 0.065" (Diameter, wall thickness). They will be connected with stainless steel tubing and KF-25 connectors with Viton gaskets. Question: I have an air conditioning service pump-- will that be able to bring the vacuum to 6 torr? Otherwise, would it be possible to create at least a 6 torr vacuum by heating (to the point of boiling) the vacuum chamber that contains water and then sealing the system? The condensing water vapor should create a powerful vacuum, correct? If an vacuum pump must be used, what is a good way to seal off the system? I have a gate valve (with elastomer seals), but it has a couple of 1/4" threaded holes in it (currently fitted with teflon and stop plugs). My concern is that system will leak through the threaded holes. Is there a recommended way to seal threads to retain vacuum?