When I first got my kiln I always worried that something in it would explode in the middle of the firing. I had a few pieces ping apart. Over time I stopped worrying because I eventually realized that there was never enough glass in there anyway to cause an actual problem if the glass thermal shocked and flew around the kiln.

I should have been worrying about watermelons. Yesterday I sat in the living room and heard a light 'pop' come out of the kitchen. It turns out that the watermelon on the counter just blew itself up. I guess it was over ripe and the gassess had to escape. It was a much bigger mess then anything I've ever seen in the kiln. Geez Who knew?