[david s]

I cast mine. I get away with it because my oven is small. Trouble is with a larger oven you will have uneven heat rise and therefore uneven expansion. So you then need to cast the dome in multiple pieces. This can be tricky for a one off design. The castable refractory is hard like concrete but never truly fired unless you fire it in a kiln and you need to go to 573 C to make the material change.