I have a Skutt Firebox and I would like to move into plates, bowls etc…I placed a 7 inch circle blank with broken pieces of glass in it with the thought of making a collage blank to then mold in a 7 inch fluted mold. I never got past the first fuse..It broke at 1100. All the glass was 90 COE as that is all I have at this time. The glass almost toched the inside of my kiln, so I am wondering if I need to scale back.