I'm currently planning on building a forge made entirely out of refractory cement by using 2 different sized concrete post tubes to create a hollowed out tube so that it will have roughly a 4inch thick wall all the way around. And be 1' 6" long so that I can cover the outside with sheet metal and insert 3 propane torches for the heating.
My questions about this setup may be rather simple for more experienced people. Will this setup work on its own and with firebrick placed inside to create a flat surface or will I need to use a insulator like kao wool to finish this off. From my understandings as long as I cast this and heat treat the cement it should be good to go however I may be unaware of anything else I should to to this forge other then cast and heat treat it to complete. Would I be better off adding a layer of insulation inside the walls or wrapped on the inside and use a sealer? Should I perhaps use walls made out of firebrick and then add a thick layer of refractory cement around it?
So far I have made my forges from firebrick and kao wool but have yet to use refractory cement.
