Bullseye Glass Mold #8454, Oval in Rectangle 9.1"

The Bullseye Glass Mold #8454 is a slumping form that shapes a glass blank into an oval contour set within a rectangular border. It is slipcast from a specially formulated clay body by Creative Ceramics in Europe and imported and sold by Bullseye Glass. The outer mold footprint of 9.1 inches by 6.1 inches by 1.5 inches deep is the measurement to check against your kiln shelf before cutting glass.

Because these molds are handmade, individual pieces vary slightly in size, so measure your specific mold before cutting your glass blank. The forming surface is exceptionally smooth, accepts kiln wash uniformly, and holds up under repeated proper use, making it a durable, reusable form. Like all ceramic slumping molds, it is COE agnostic and works with any fusible glass.

What shape does Bullseye mold #8454 produce?
It slumps glass into an oval shape set within a rectangular profile. Place a pre-cut or fused glass blank on the prepared form and fire until gravity pulls the glass into the oval contour.

What are the outer dimensions of this mold?
The outer mold measures 9.1 inches long by 6.1 inches wide by 1.5 inches deep (23 by 16 by 4 cm). These dimensions are for checking kiln clearance. Since the molds are handmade, individual pieces vary slightly, so measure your mold before cutting glass.

What COE glass works with this mold?
Any COE. Ceramic slumping forms are COE agnostic, so COE90, COE96, and other fusible glass all work in the same mold. Match your firing schedule 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 mold separator and let it dry completely before placing glass. The surface accepts kiln wash uniformly for clean, consistent release.

Specifications

• SKU: 153139
• Manufacturer: Bullseye Glass (made by Creative Ceramics in Europe; design #8454, item 008454-MOLD-M-EACH; store code BG8454)
• Shape: oval in rectangle
• Outer mold size: 9.1 in L x 6.1 in W x 1.5 in deep (23 x 16 x 4 cm)
• Material: slipcast clay body, reusable slumping form
• Glass: any COE (COE agnostic)

Working Notes

These are guidelines, not guarantees. Every kiln fires a little differently, so test a 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 mold separator such as ZYP Boron Nitride Mold Primer, and let it dry completely before placing glass.
• Because these molds are handmade, sizes vary slightly between pieces. Measure your specific mold before cutting glass. The outer dimensions are for checking kiln fit, not the finished glass size.
• Place a pre-cut glass blank or fused piece on the prepared form. Fire to the lowest temperature that fully forms the glass into the oval shape, and visually confirm the slump during firing.
• The mold is COE agnostic. Adjust the anneal soak temperature to match your glass: about 900 F for COE90 or 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 slumping 6mm pieces in a Paragon GL24. It is not a guarantee. Every kiln fires differently and glass styles vary in viscosity. 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 COE90 glass. If using COE96, adjust this temperature to 950 F. Segment 4 cools at the kiln's natural rate with the door closed to room temperature.

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

Description updated: July 6, 2026

Spot an error or have feedback on this description? Report it here.