Ceramic shell and castable wax (purple)

Has anyone tried to use ceramic shell molds to burnout and cast the castable wax? My molds completely broke during burnout (large scale pieces, 6-8”) We also used filament prints for our patterns and those worked great! We put the molds in a large and hot kiln (1200 f) for a flash burnout.

Any tips would be greatly appreciated! Thanks

Did you create a shell of your model so it’s not solid? I would assume with the size that it was somewhat hollow. What application are you using?

I was trying to make an actual size rubber chicken once, and in ZBrush I created a shell that was about 0.7mm thick. It had a blowout and was too fragile, but perhaps making a hollow model is the key?

Are you using any fiberglass with the shell mold? I cast glass, and we use a chopped fiberglass to reinforce the refractory plaster/investment.