Through my research online I have found a recipe to make the walls and floor out of but I don't know how to tell what kind of temperatures it will withstand. What happens when they are heated too much?
The recipe I found is as follows:
1 part by volume of Perlite (NOT VERMICULITE)
2 part by volume of Fire Clay (Refractory Clay)
1 part by volume of Sand (Silica, as pure as possible)
1 part by volume of Ash (Finely Ground)
1 part by volume of Portland Cement (Mason's Cement Doesn't Work/ Nor does Concrete)
Allow for MULTIPLE days to dry and then SLOWLY heat to final temperature!
I copied that from another forum but I cant find anything on maximum temperature. If it helps I also have another handful of recipes that I have copied but they are for the most part fairly similar.