I am needing to pot some temp sensors in thermowells and curious what compound might be used for this and where to get it? I would assume a highly thermal conductive material and can expand with the metal thermowell.

Wolfra-coat C 60 g tube, suitable for -30- 1200 C

I should have spec'd our temp range. I am sure the above is damn pricey. We will only need -30F-300F on this application.