Here are a couple of photos of the kiln disaster. It was a copper red firing and the bottom octagonal shelf just melted with all the weight on it. This first photo is before anything was unstacked, and you can see that the bottom shelf appears to be missing. It's in there somewhere.
This next one is of a piece of that bottom shelf. Hard to believe it was rated for cone 10, but I have fired those shelves to cone 10 many times, just not with so much weight on them.
This final photo is also of that bottom shelf, the largest piece of all the ones I chipped out. It's stuck to the kiln post, and there is major glaze running.
The shelves above the copper reds were fairly OK. The pots all need to be refired, but they did not collapse as they might have. There is lots of pinholing on the glazes, but I have seen worse come out beautiful in a second firing.
I fired the kiln yesterday to red heat just to make sure the patching was dry -- it has been a month -- and the new target brick, a 12 x 12 x 1 inch slab of alumina, would be able to withstand a burner about 10 inches away and not crack.
The alumina slab came from a friend and it weighs 22 pounds. When I picked up the package I was really surprised by the weight. I was expecting maybe 8 pounds. I've not unstacked it yet so don't know whether the slab is OK.