I want to build a speciality furnace. I have the resistor wire. I am looking for the white cement that one sees in kilns or laboratory furnaces. It is similar to pumice. You can cast the resistor wire inside of the cement. Does anyone know what the cement is called and where can I purchase it. Many thanks.

I am hoping to start working with stainless spring steel soon but had a question about heat treating it. Annealing is not a problem, but when doing some research I saw that you need to bring the kiln to 900 degrees and maintain that temperature for a specified time. Does anyone know whether you put the piece in the kiln then bring it up to temp, or do you allow the kiln to pre-heat to the specified temp then insert the piece?