Bullseye Glass Mold #8634, Square Slumper A 10.1"

The Square Slumper A mold from Bullseye Glass (design #8634) is a 10.1 inch square slumping form. A pre-cut glass sheet or fused blank is placed over the surface, then fired so the glass softens and settles by gravity into the square shape. The result is a gently curved square dish or panel with a smooth finish on the forming side.

The outer mold dimensions are 10.1 inches by 10.1 inches by 1.9 inches tall (26 x 26 x 5 cm). These are the kiln-fit dimensions. Because each mold is handmade and may vary slightly in size, measure the actual mold before cutting your glass. The mold is slipcast from a specially formulated clay body by Creative Ceramics in Europe and imported by Bullseye Glass. Its exceptionally smooth surface accepts kiln wash uniformly and does not crack under repeated proper use.

What does this mold make?
It slumps a flat glass sheet or fused blank into a 10.1 inch square form. The finished piece has a gently curved profile shaped by gravity over the mold surface.

What COE glass can I use?
Any COE. Ceramic slumping forms are COE agnostic, so the same mold works with COE96, COE90, or other fusible glass. Match your slumping schedule to the glass you are using.

How do I prepare the mold?
Coat the forming surface with a kiln wash such as Hotline Primo Primer and let it dry completely before placing your glass. A boron nitride primer such as ZYP also works. Recoat as needed between firings.

How do I size my glass for this mold?
The listed outer dimension is 10.1 inches square, but measure the actual mold before cutting since each piece is handmade and sizes can vary slightly. Cut your glass to fit the top of the form.

Specifications

• SKU: 3654
• Manufacturer: Bullseye Glass (made by Creative Ceramics; design #8634, item 008634)
• Makes: 1 square slumped dish or panel
• Finished piece size: approximately 10.1 inches square
• Mold outer dimensions: 10.1 in L x 10.1 in W x 1.9 in H (26 x 26 x 5 cm)
• Material: slipcast ceramic, handmade by Creative Ceramics in Europe, imported by Bullseye Glass; reusable
• Glass: 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 and let it dry fully before placing your glass. A boron nitride primer such as ZYP Boron Nitride Mold Primer also works.
• Place a pre-cut glass sheet or fused blank over the top of the mold. The glass will slump and take the form's shape as it heats.
• Measure the actual mold before cutting your glass. Each mold is handmade and may vary slightly from the listed dimensions.
• The mold is COE agnostic. Use a slumping schedule matched to your glass, and adjust the anneal soak temperature for your COE (about 900 F for COE90, about 950 F for COE96).
• Let the kiln cool fully before removing the slumped piece. Recoat the forming surface with kiln wash as needed between firings.

Bullseye Suggested Slumping Schedule

This is a suggested starting schedule based on Bullseye's guidance for 6mm glass in a Paragon GL24 kiln, not a guarantee. Every kiln fires differently. Visually confirm the slump during firing and adjust as needed.

The anneal soak in segment 2 is listed at 900 F. If using COE96, adjust this soak to about 950 F. Segment 4 is a natural cool with the kiln door closed, no active ramp.

Helpful downloads: Suggested Slumping Schedules from Bullseye Glass (PDF)

Description updated: July 6, 2026

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