the sillica in fire bricks could be replaced with powdered glass
clay & powdered glass & heat = fire brick
cement mixer & large steel ball bearings/ hard rocks & broken glass = powdered glass
You definitely need refractory cement for the mortar in the firebox portion.
You can save money on refractory cement by using this mortar recipe instead (trust me, I'm a mason)
3 parts sand:1part portland cement:1part powdered fireclay
Refractory cement is great stuff, but hella expensive. I does come in gallon cans though, so if your fire box is small it may be the way to go.
Sol McCoy wrote:fire clay is milled porcelain...