Ok thanks for the info on both counts. I actually thought that Tef-Gel was an insulator so that clears it up.

I have had some conflicting instructions on how to mount sacrificial anodes from engineers whose opinions i respect. Take the example of a "zinc rod mounted in a brass base" which is to be fitted to a tube type heat exchanger for a sea water system. 1. Do i coat the brass thread in tef-gel...