We use float glass in the UV molds, cutting 4mm thick pieces for the base, enough to pile up to be level with the top of the foot depression. Usually 5 pieces. They are cut in 'steps' to follow the splay on the base area. In other words, the first piece might be 160mm across, the second is cut 165 across, 3rd piece 170 etc. This stops the top glass from rolling into the space that will be left between the foot pieces and the side of the mold as they are fusing.The foot pieces are washed and placed in the base. The top piece is best if is 5 or 6 mm thick. Decorate as desired and place this on the mold.

Remember if the mold has steep sides, the decoration pieces must be placed so they do not slide down the sides of the bowl as it is slumping!
The top piece will slump down, and fuse to the base pieces which have fused into a solid piece.

The UV range having the very heavy "foot" of glass, need to be annealed at a slow rate to allow for this thickness. No faster than 300F down to cold. Remember there is at least 20 to 25 mm of glass in the base!

The soft glass - Bullseye, Spectrum, etc. would have to have the top layer fused flat to make 6mm thickness before then stacking the base of the mold, and firing again to fuse and slump the top to the base. This might
have to be watched to judge the correct temperature, as the soft glass does behave differently depending on the color!

In the UV range, the UVSQR and the UVRTRI have steeper sides that the others, so to achieve the best with an applied design, a fused flat tile should be made first to avoid the shift and "avalanching" that could occur in the pattern pieces.


NOTES ON USE AND CARE OF DRAGON GLASS SLUMPING MOLDS
Dragon Glass molds are made from refractory clay, and so need to be treated with a certain amount of care.
Dragon Glass molds do not have to be ‘burnt off’ before using, they are ready to use from the box.

When you receive your new mold, it needs to be wiped over with a damp sponge to remove any dust from the manufacturing process. This will ensure that the first layer of mold release/kiln wash will adhere properly to the surface.

The occasional high spot or depression can be sanded smooth with a bisque file, nail file or fine sand paper.

The molds can be dried in the kiln after washing and coating with mold release.

For top loading glass kilns i.e., shallow “coffin” type glass kilns with elements in the roof - dry on a fast ramp with the lid vented approximately 3 cm (1?”) until no more moisture is evident, around 250oC to 300oC (400oF) Let kiln cool to around 180oC (350oF) before opening the lid wide. This is to avoid ‘shocking’ the molds. Fast ramp should be approx. 700oC per hour (1290oF) This applies to front loading kilns as well.

All clay molds must not be crash cooled below 650 oC (1200F). IMPORTANT

When the kiln is in the down, or annealing cycle, it should not be opened hotter than 280oC (535oF), then can be opened 3 cm (1”), until glass can be handled without gloves.