Bullseye Glass Mold #8920, Long Oval Serving Bowl 10.9"

The Long Oval Serving Bowl mold from Bullseye Glass (design 8920) is a slumping form that shapes a prepared glass sheet or fused blank into a long, narrow oval bowl about 10.9 inches in length. A flat glass piece is laid on the form and fired in the kiln until the glass softens and gravity draws it down into the bowl profile.

The outer dimensions of this mold are 10.9 by 4.5 inches, with a form height of 0.6 inches. These molds are handmade slipcast forms, so sizes vary slightly from piece to piece, and you should measure your mold before cutting any glass rather than relying on the listed dimensions alone. The slipcast clay body has an exceptionally smooth surface that accepts kiln wash uniformly and does not crack under repeated proper use. Bullseye produces this mold through Creative Ceramics in Europe and imports it as part of its kiln forming tool line.

What does this mold make?
It forms one long oval serving bowl approximately 10.9 inches long. A flat or fused glass blank is placed on the form and slumped in the kiln until the glass conforms to the bowl shape.

How does slumping work with a form like this?
A prepared glass blank is centered on the mold and loaded into the kiln. As the kiln heats, the glass softens and gravity draws it down to conform to the long oval bowl shape. The glass retains that bowl profile as the kiln cools.

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

How do I know what size glass blank to cut?
The listed dimensions (10.9 x 4.5 x 0.6 in) are the outer dimensions of the mold itself, not the glass blank dimensions. Because these molds are handmade and vary slightly in size, measure your mold directly before cutting any glass.

Specifications

• SKU: 152811
• Manufacturer: Bullseye Glass (design 8920, item 008920-MOLD-M-EACH; made by Creative Ceramics, Europe)
• Store model code: BG8920
• Makes: 1 long oval serving bowl
• Mold outer dimensions: 10.9 x 4.5 x 0.6 in (28 x 11 x 2 cm); handmade, measure before cutting glass
• Material: slipcast ceramic, exceptionally smooth surface, 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 a kiln wash such as Hotline Primo Primer and let it dry completely before placing glass on the mold. You may also prime with a boron nitride mold primer such as ZYP Boron Nitride Mold Primer.
• Measure the mold directly before cutting your glass blank. Because these forms are handmade, individual mold sizes vary from the listed spec.
• Center the prepared glass blank on the form and load onto a level kiln shelf.
• The mold is COE agnostic. Match your slumping schedule and anneal soak temperature to the glass you are using.
• Let the kiln cool fully before removing the slumped bowl. Re-coat the mold surface with kiln wash as needed between firings.

Bullseye Suggested Slumping Schedule

This is a suggested starting schedule based on Bullseye's published guidance for this mold, developed for 6mm glass in a Paragon GL24 kiln. It is not a guarantee. Every kiln fires differently, glass viscosity varies by style, and form depth affects the required slump temperature. Visually confirm the slump during firing and adjust as needed for your glass and kiln.

*AFAP means as fast as possible: let the kiln drop to that temperature at its natural rate with the door closed. The anneal soak in segment 2 is set at 900 F, which suits Bullseye glass. If using COE96 glass, adjust the anneal soak temperature to approximately 950 F.

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

Description updated: July 6, 2026

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