I like David's advice. Get the mortar outta there, and repoint new mortar in. I have done some experimenting with cracked pieces and Refrax to see what would happen, and the results are good. In fact, we completely assembled a Forno Bravo oven that had been dropped by the shipper and destroyed. We put it together with a lot Refrax (inside and out) and it cooks great and is lasting well. Don't do this at home, but it was a good thing to know.
Is it only the mortar that is calling in? Are the oven dome pieces themselves holding up and not cracking or starting to spall (flake)? If the dome is in good shape and it is just the mortar, I think it will work well.
I would highly recommend Refrax over the U.S. made mortar. I know that it will stand up to the heat and thermal cycling.
James |