Even if you are discussing only a very low total pressure of O2 (that is, the threads are at chamber pressure), it is still 100% partial pressure and Apiezon L is a wonderful fuel. Why risk it?
My thread seal choices would be: 1. Get rid of the thread that needs sealing if this is not possible 2. At high pressure (>1 torr) – Teflon (plumber’s) tape 3. At chamber pressure (<1 millitorr) - a silicone sealant like our KL-5 (correctly cured before exposed to the oxygen) sprayed on the joint after it has been made. For solution 3 you should seal the atmosphere surface. You don't want a large area of KL-5 inside the chamber even though its outgassing characteristics (after curing) are good. However, this leaves the thread as a wonderful virtual leak that will probably cause you pumpdown time grief.
Related Questions
- Even if you are discussing only a very low total pressure of O2 (that is, the threads are at chamber pressure), it is still 100% partial pressure and Apiezon L is a wonderful fuel. Why risk it?
- Why do winds rotate counter-clockwise in the northern hemisphere around low pressure?
- What is the difference between high pressure and low pressure tanning beds?
