Bullseye Glass Mold #8734, Ball Surface 11.4"

The Bullseye Glass Mold #8734 is an 11.4 inch slumping form with a ball surface texture. A sheet of fusible glass or a pre-fused blank is placed over the form, then fired so the glass softens and takes the ball surface shape by gravity. The finished piece carries a rounded ball pattern across its surface.

The mold is slipcast from a specially formulated clay body by Creative Ceramics in Europe and is imported and sold by Bullseye Glass. The outer dimensions are 11.4 by 3 inches (29 by 8 cm), which is the footprint to account for when loading the kiln. Because these molds are handmade, individual pieces vary slightly in size, so measure your mold before cutting glass to fit it. The surface is exceptionally smooth, accepts kiln wash uniformly, and does not crack under repeated proper use.

What does this mold make?
It slumps glass into a piece with a ball surface texture, about 11.4 inches across. The mold imprints a rounded, repeating ball pattern on the glass as it softens and settles over the form.

How does a slumping mold work?
A cut glass sheet or fused blank is placed over or set into the form on a prepared kiln shelf. As the kiln heats, the glass softens and drapes to follow the mold surface by gravity, then holds its new shape as the kiln cools.

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

How do I prepare the mold before firing?
Coat the forming surface with kiln wash or a boron nitride primer and let it dry completely before placing glass on the mold. Re-coat as needed between firings.

Specifications

• SKU: 157131
• Manufacturer: Bullseye Glass (BG8734; slipcast by Creative Ceramics, imported by Bullseye)
• Bullseye design number: 8734 (item number 008734-MOLD-M-EACH)
• Technique: glass slumping and draping
• Mold outer dimensions: 11.4 x 3 in (29 x 8 cm)
• Fit note: molds are handmade and vary slightly; measure before cutting glass
• Surface: exceptionally smooth, accepts kiln wash uniformly
• Material: slipcast ceramic, 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 boron nitride primer such as ZYP Boron Nitride Mold Primer and let it dry completely before placing glass on the mold.
• These molds are handmade, so measure your mold before cutting glass to fit it. Individual pieces 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 for your COE.
• Visually confirm the slump during firing and adjust the hold time or temperature as needed for your kiln and glass.
• Let the kiln cool fully before removing the slumped piece. Re-coat the mold with kiln wash or primer as needed between firings.

Bullseye Suggested Slumping Schedule

This is a suggested starting schedule based on slumping 6mm pieces in a Paragon GL24 kiln. It is not a guarantee. Every kiln fires differently and glass styles vary in viscosity. Visually confirm the slump during firing and adjust. Follow Bullseye's published Suggested Slumping Schedule guidance for your glass and mold.

AFAP means as fast as possible (the kiln's natural rate). Segment 4 lets the kiln cool to room temperature at its natural rate with the door closed. The anneal soak in segment 2 is at 900 F; adjust this temperature for your COE if needed (about 950 F for COE96).

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

Description updated: July 6, 2026

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