Bullseye Glass Mold #8633, Drop Out Ring 7.1"

The Drop Out Ring mold from Bullseye Glass (design #8633) is a ring-shaped ceramic slumping form with an outer diameter of 7.1 inches and an inside opening of 3 inches. A flat glass blank or fused piece, cut to overhang the ring, is set on top of the form. As the kiln heats up, the glass softens and the center drops through the inside opening by gravity, while the edges rest on the ring and stay elevated. The finished result is a rounded bowl or vessel whose depth and profile are shaped by the firing.

The mold is slipcast from a specially formulated clay body by Creative Ceramics in Europe and imported by Bullseye Glass. It has an exceptionally smooth surface, 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. Molds are handmade and vary slightly in size, so measure your specific mold before cutting glass.

What does the Drop Out Ring mold make?
It forms a rounded bowl or vessel from a flat glass blank. The center of the blank softens and drops through the 3 inch inside opening during firing, creating a curved piece whose depth and profile depend on the firing temperature and hold time.

How does a drop out ring work?
A flat glass blank or fused piece is cut larger than the ring's 7.1 inch outer diameter and placed on top of the form. During firing the unsupported center softens and drops through the inside opening by gravity. The edges of the glass rest on the ring and stay elevated, forming the rim of the finished piece.

What size glass blank do I need?
The blank must be large enough to rest on the ring, which has an outer diameter of 7.1 inches. Molds are handmade and vary slightly in size, so measure your specific mold before cutting glass and allow a small overhang on all sides.

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

Specifications

• SKU: 5102
• Manufacturer: Bullseye Glass (BG8633, design #8633, item 008633-MOLD-M-EACH), made by Creative Ceramics, imported by Bullseye
• Makes: drop out slumped bowl or vessel
• Outer diameter: 7.1 inches (18 cm)
• Height: 0.4 inches (1 cm)
• Inside opening: 3 inches (8 cm)
• Material: slipcast ceramic slumping form, reusable
• Glass: any COE (COE agnostic)

Working Notes

These are guidelines, not guarantees. Every kiln fires a little differently, so test a small run 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 use a boron nitride mold primer such as ZYP Boron Nitride Mold Primer. Recoat as needed between firings.
• Cut the glass blank larger than the ring's 7.1 inch outer diameter so it rests on the form. Molds are handmade and vary slightly in size, so measure your specific mold before cutting glass.
• The mold is COE agnostic. Use a slumping schedule matched to your glass type and follow Bullseye's published Suggested Slumping Schedule for your glass and mold depth.
• Visually confirm the slump is complete during firing if your kiln allows, and adjust temperature or hold time as needed for your kiln and glass.
• Let the kiln cool fully to room temperature before removing the formed piece. Recoat the mold 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 and glass styles vary in viscosity. Follow Bullseye's published Suggested Slumping Schedule for your glass and mold depth, visually confirm the slump during firing, and test a small piece first.

AFAP means as fast as possible (the kiln heats or cools at its natural rate). Segment 4 is a natural cool to room temperature with the door closed. The 900 F anneal soak in segment 2 is suited to COE90 glass. If using COE96, adjust the anneal soak temperature to about 950 F. 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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