Bullseye Glass Mold #8636, Square Slumper A 4.5"

The Square Slumper A mold from Bullseye Glass slumps a flat glass blank into a shallow square form in a single firing. Carrying Bullseye design number 8636, the mold has an outer footprint of 4.5 inches by 4.5 inches and a depth of 0.8 inches. A pre-cut square blank or a fused piece is placed on or into the form, then heated until the glass softens and settles into the shape by gravity.

The form is slipcast from a specially formulated clay body by Creative Ceramics in Europe and imported by Bullseye Glass. The surface is exceptionally smooth, accepts kiln wash uniformly, and does not crack under repeated proper use. Like all ceramic slumping forms it is COE agnostic and reusable across many firings.

What does the Square Slumper A mold make?
It slumps a flat glass blank into a shallow 4.5 inch square form. Finished pieces work well as small square dishes, decorative accent tiles, or components for larger assembled works.

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

What size glass blank do I cut?
The outer mold footprint is 4.5 inches by 4.5 inches. These forms are handmade and may vary slightly in size, so measure the mold directly before cutting your blank rather than relying on the listed dimensions alone.

How do I prep the mold before slumping?
Coat the forming surface with a kiln wash such as Hotline Primo Primer or a shelf primer and let it dry completely before placing your glass. Bullseye's clay body accepts kiln wash uniformly, so standard kiln wash applies evenly across the surface.

Specifications

• SKU: 4480
• Manufacturer: Bullseye Glass (design #8636, item 008636-MOLD-M-EACH; slipcast by Creative Ceramics in Europe, imported by Bullseye)
• Makes: slumped square glass form
• Outer mold size: 4.5 inches L x 4.5 inches W x 0.8 inches H (12 x 12 x 2 cm)
• Material: slipcast ceramic kiln form, 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 or a shelf primer such as ZYP Boron Nitride Mold Primer and let it dry completely before placing your glass.
• Cut or fuse your glass blank to fit the mold. Measure the mold before cutting, as these forms are handmade and may vary slightly from the listed outer dimensions.
• The mold is COE agnostic. Use a slumping schedule matched to your glass, and adjust the anneal soak temperature to suit your glass type.
• Visually confirm the slump during firing and pull from the target temperature as soon as the glass has fully settled into the form. Let the kiln cool completely before removing the finished piece. Re-coat the forming surface with kiln wash between firings as needed.

Bullseye Suggested Slumping Schedule

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

Segment 2 is the anneal soak at 900 F, suited to Bullseye glass. Segment 4 is a natural cool: close the kiln door and let it reach room temperature on its own. Adjust the anneal soak temperature to match the specific glass you are using.

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

Description updated: July 6, 2026

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