[gjbingham]

Dusty,
Very similar to my cracks, though I've got two good ones in the dome (that I can see). One goes right through a brick, just like yours does. I never would have guessed that would happen. The expansile forces must be pretty awesome while heating.

Regarding the arch crack, my cracks seal up as the dome cools, just as yours. I would think that the arch crack would close before the bricks got anywhere near a temp. that you could actually get mortar in there before all the moisture sizzled out of your mix. Someone mentioned shimming a crack while it was hot, then filling it once cold. I think that would just give the existing crack a new baseline from which to expand, and possibly make things worse.

My own gut reaction to your problem is to finish curing the dome, then do several really hot cooking fires, then repair any real damage.

George