Bullseye Glass Mold #8631, Drop Out Ring 10.8"

The Drop Out Ring mold from Bullseye Glass is a slumping form with an outer diameter of 10.8 inches and an inside opening of 6.7 inches. A flat glass blank is placed over the ring so the outer rim rests on the mold surface and the center of the glass sits unsupported above the 6.7 inch opening. As the kiln reaches slump temperature, the center softens and drops down through the inside opening, forming a piece with a supported flat rim and a freeform dropped center.

The ring body is 0.5 inches (1 cm) deep and the outer diameter is 10.8 inches (28 cm). The inside opening is 6.7 inches (17 cm) across. These molds are slipcast from a specially formulated clay body by Creative Ceramics in Europe and imported by Bullseye Glass. The surface accepts kiln wash uniformly and the mold does not crack under repeated proper use. Because each mold is handmade, dimensions vary slightly from piece to piece, so measure your specific mold before cutting glass.

What does the Drop Out Ring mold make?
It shapes a slumped piece with a flat outer rim and a dropped center. The center of the glass blank softens over the 6.7 inch inside opening and drops down during firing while the outer rim stays supported on the ring.

What size glass blank do I need?
A round blank cut to approximately the outer diameter of the mold, about 10.8 inches, rests on the ring with its center over the inside opening. Because each mold is handmade and dimensions vary slightly, measure your mold before cutting.

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

How do I prep this mold?
Coat the top surface of the ring with kiln wash or shelf primer and let it dry completely before placing glass. These molds accept kiln wash uniformly.

Specifications

• SKU: 156613
• Manufacturer: Bullseye Glass (design #8631, item 008631-MOLD-M-EACH; store model code BG8631)
• Makes: slumped piece with flat outer rim and dropped center
• Outer diameter: 10.8 inches (28 cm), for kiln fit
• Ring depth: 0.5 inches (1 cm)
• Inside opening: 6.7 inches (17 cm)
• Material: slipcast clay body, made by Creative Ceramics in Europe, imported by Bullseye Glass; reusable slumping form
• 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 top surface of the ring with kiln wash or a boron nitride mold primer such as ZYP Boron Nitride Mold Primer, and let it dry completely before placing glass.
• Molds are handmade and sizes vary slightly. Measure your specific mold before cutting your glass blank.
• Place a round blank centered over the ring so the outer rim of the glass rests on the mold surface and the center is positioned above the 6.7 inch inside opening.
• Monitor the drop visually during firing if your kiln allows it. The glass center softens and drops when slump temperature is reached.
• The mold is COE agnostic. Use a slumping schedule matched to your glass and adjust the anneal soak temperature for your COE.
• Let the kiln cool fully before removing the slumped piece. Re coat the mold 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, not a guarantee. Every kiln fires differently. Follow Bullseye's published slumping guidance for your glass and kiln, and test a small piece first.

AFAP means as fast as possible. Segment 2 is the anneal soak at 900 F, suited to COE90 glass. If using COE96, adjust the soak temperature to about 950 F. Segment 4 lets the kiln cool at its natural rate with the door closed. Note: Bullseye's published 1250 F / 1:30 schedule for this mold is for making a shallow plate with the mold placed directly on the kiln shelf, not elevated. For a deeper drop with the mold elevated, adjust the firing and confirm the drop visually.

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

Description updated: July 6, 2026

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