Q: I need a bolt that can handle high temperatures and be an electric insulator? What can I use?
A: That depends on what you mean by high temperature and what other issues you have like the strength requirements. If you are talking about temperatures under 500F, then you may consider some engineered polymers. They are non-conductive both electrically and thermally. PEEK is the most economic choice up to about 500F. If you are talking about higher temperatures, then you would have to go with a ceramic like alumina which is an excellent insulator and resistant to heat well over 2000F