Q: I have a need for a fastener for cyrogenic Helium (3.5K) application. Ideally, the fastener would be non conductive (electrically). Are any of the non conductive options you have listed good for cryo use?
A: You might want to consider PTFE of PEEK fasteners. These are polymers that will be able to withstand a cryogenic environment and be non-conductive. PTFE fasteners differentiate themselves by being more corrosion resistance. They offer protection from most organic materials, acids and bases – even hydrochloric acid. PEEK screws would be a good choice for high strength as they offer higher strength than PTFE, PFA, PVDF and Vespel. Glass filled PEEK fasteners can be almost as strong as some grades of steel.