The Square Platter 9.6 mold from Bullseye Glass (design #8638) is a ceramic slumping form that shapes a pre-cut glass blank into a square platter in a single firing. You lay a sheet of fusible glass over the form, set it in the kiln, and fire slowly so the glass softens and drapes down over the mold by gravity, taking on the square platter profile.
The outer footprint is 9.6 by 9.6 inches, with a height of 0.8 inches, giving you the measurement you need to check whether the mold fits your kiln shelf. The inside forming area is 5 by 5 inches with a depth of 0.6 inches. These molds are slipcast from a specially formulated clay body by Creative Ceramics in Europe and imported by Bullseye Glass. Each one is handmade and varies slightly in size, so measure your specific mold before cutting your glass blank. The exceptionally smooth surface accepts kiln wash uniformly and holds up well across repeated firings with proper care.
What does mold #8638 make?
What are the mold dimensions?
What COE glass can I use?
How do I prepare this mold for slumping? Hotline Primo Primer or a shelf primer and let it dry completely before placing your glass. The smooth slipcast surface accepts kiln wash uniformly. Recoat the mold between firings as needed.
Specifications
SKU: 3656Manufacturer: Bullseye Glass (made by Creative Ceramics in Europe; store model BG8638, Bullseye design #8638, item 008638-MOLD-M-EACH)Makes: one square platter per firingInner forming area: 5 x 5 x 0.6 in (12 x 12 x 1 cm)Outer mold size: 9.6 x 9.6 x 0.8 in (25 x 25 x 2 cm)Sizing note: molds are handmade and vary slightly; measure before cutting glassMaterial: slipcast ceramic kiln slumping form, reusableGlass: any COE (COE agnostic)
Working Notes
These are guidelines, not guarantees. Every kiln fires a little differently, so test a small piece first when the result matters and follow a slumping schedule suited to your glass and kiln.
Coat the forming surface with kiln wash or a shelf primer such as ZYP Boron Nitride Mold Primer , and let it dry completely before placing your glass blank.
Each mold is handmade by Creative Ceramics and varies slightly in size. Measure your mold before cutting your glass blank to fit.
This mold is COE agnostic. Adjust the anneal soak in segment 2 to match your glass: 900 F as listed suits COE90; for COE96, adjust to 950 F.
Visually confirm the slump during firing when possible. If the glass is not fully formed by the end of segment 1, extend the hold before moving on.
Let the kiln cool fully to room temperature before removing the piece. Recoat the mold with kiln wash as needed between firings.
Bullseye Suggested Slumping Schedule
This is a suggested starting schedule based on slumping a 6mm piece in a Paragon GL24 kiln, not a guarantee. Every kiln fires differently and glass styles vary in viscosity. Follow Bullseye's published guidance for your glass and mold, and test a small piece first.
Segment Purpose Rate (F/hr) Temp (F) Hold 1 Slump 300 1250 1:30 2 Anneal soak AFAP 900 1:00 3 Anneal cool 100 700 none 4 Cool to room temp AFAP 70 none
AFAP means as fast as possible (the kiln drops at its natural rate with the door closed). The anneal soak in segment 2 is listed at 900 F, which suits COE90 glass. For COE96 glass, adjust this soak temperature to 950 F.
Helpful downloads: Suggested Slumping Schedules from Bullseye Glass (PDF)
Description updated: July 6, 2026
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