Bullseye Glass Mold #8933, Concave Dish 13.9"

The Bullseye Glass Mold #8933 is a concave dish slumping form that shapes a flat glass sheet or fused blank into a shallow, oval concave dish by gravity in the kiln. The outer mold dimensions are 13.9 inches by 9.5 inches by 1.7 inches deep, serving as a guide for kiln placement and for sizing your glass blank before cutting. Because these molds are handmade by Creative Ceramics in Europe and imported by Bullseye Glass, individual dimensions vary slightly from piece to piece, so always measure your mold before cutting glass.

The form is slipcast from a specially formulated clay body that produces an exceptionally smooth surface, accepts kiln wash uniformly, and holds up to repeated proper use without cracking. Like all ceramic kiln molds, it is COE agnostic: use it with COE90, COE96, or any compatible fusible glass, and match your firing schedule to the glass you choose.

What shape does this mold produce?
It slumps a flat glass blank into a shallow concave dish, roughly oval in plan. The finished piece follows the mold interior and is suited to decorative display or functional use as a small dish.

What size glass blank do I need for this mold?
The outer mold dimensions are 13.9 by 9.5 inches. Since these molds are handmade and vary slightly between pieces, measure your specific mold before cutting glass and size the blank to drape fully into the concave form.

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

How do I prep this mold before firing?
Coat the forming surface with a kiln wash such as Hotline Primo Primer or a shelf primer and let it dry fully before placing glass. The surface accepts kiln wash uniformly, making prep consistent. Re-coat as needed between firings.

Specifications

• SKU: 153705
• Manufacturer: Bullseye Glass (slipcast by Creative Ceramics in Europe, imported by Bullseye)
• Design number: 8933 (item number 008933-MOLD-M-EACH; store code BG8933)
• Form type: Concave dish slumping mold
• Outer mold dimensions: 13.9 x 9.5 x 1.7 inches (35 x 24 x 4 cm)
• Note: Handmade; dimensions vary slightly between pieces. Measure your mold before cutting glass.
• Material: Slipcast ceramic (specially formulated clay body), reusable
• Glass: Any COE (COE agnostic)

Working Notes

These are guidelines, not guarantees. Every kiln fires a little differently, so test with your glass and kiln before committing to a full project run, and follow Bullseye's published slumping guidance for your mold depth and glass.

• Coat the forming surface with kiln wash or a shelf primer, such as ZYP Boron Nitride Mold Primer, and let it dry completely before placing glass.
• Measure your mold before cutting glass. Place the blank centered on the concave form and confirm it is positioned to drape evenly as it softens.
• This mold is COE agnostic. Use a slumping schedule matched to your glass, and adjust the anneal soak temperature for your COE (about 900 F for COE90 or 950 F for COE96).
• Visually confirm the slump during firing if your kiln allows, and adjust the hold time or peak temperature as needed for your setup and glass style.
• Let the kiln cool fully before removing the piece. Re-coat the forming surface with kiln wash as needed between firings.

Bullseye Suggested Slumping Schedule

This is a suggested starting schedule for slumping 6mm pieces in a Paragon GL24, 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.

AFAP means the kiln drops at its natural rate with the door closed. Segment 2 anneal soak is shown at 900 F, appropriate for Bullseye COE90 glass. If using COE96 glass, adjust the segment 2 anneal soak to approximately 950 F.

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

Description updated: July 6, 2026

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