We are seeing the same issue with the K26 bricks that we had with the K23's.  We have now had several of them fracture apart.  They are Morgan Thermal Ceramic K26's.  The latest one was handled nicely and used as a rear baffle wall for a short time.  We don't like it as they are convenient but we are now looking to cast baffle walls with kast o lite and blanket.   There is another forge in the shop.  This one is another oval forge with a bottom mounted burner.  It is 185 in³.  The oval is a