Asked by: Ncbixii

Answered by: Dave03060

Yes and no. As an outer shell, yes. As a liner, absolutely not. Concrete can fail explosively at high heat and cause severe damage and injury, it will also degrade at high heat. An insulating refractory lining with refractory mortar is mandatory. Ceramic wool with a rigidizer or insulating firebrick with furnace cement in the joints is the minimum recommended. Please talk to someone with more experience before you get hurt! There are lots of tutorials online and anyone who has built a kiln will know what the issues are. A welded steel frame is better than concrete blocks as it will not rub the softer firebrick as harshly and wear it as much. But concrete or even cinder block will work for an infrequently used forge if carefully insulated. Without good, intact insulation, it is a bomb waiting to detonate.