Bullseye Glass Mold #8997, Square Slumper B with Flat Base 5.2"

The Square Slumper B with Flat Base mold from Bullseye Glass (design 8997) is a square slumping form that shapes a pre-cut fusible glass sheet into a small square dish with a flat floor and rising sides. A flat glass blank is placed over or set into the form, then fired slowly until the glass softens and gravity draws it down to follow the mold's contours. The flat base profile keeps the finished piece level and stable on a flat surface.

The outer mold dimensions are 5.2 by 5.2 by 1.3 inches (13 by 13 by 3 cm). These measurements describe the exterior of the form and are provided to help you confirm the mold fits your kiln shelf. Because each mold is slipcast by Creative Ceramics in Europe and imported by Bullseye Glass, individual pieces vary slightly in size, so measure your specific mold before cutting your glass blank. The specially formulated clay body accepts kiln wash uniformly and does not crack under repeated proper use.

What does the Square Slumper B with Flat Base make?
It slumps a flat glass sheet into a square dish with a flat base, sized to the interior of the mold. The flat floor makes the finished piece stable, suited to use as a small tray, decorative dish, or plate.

What size glass blank do I need?
You need a blank large enough to span the opening of the form and allow the sides to form as the glass slumps into the mold. Because these molds are handmade and vary slightly in size, measure your specific mold rather than relying on the listed outer dimensions before cutting your glass.

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

How do I prep the mold before slumping?
Coat the forming surface with a kiln wash such as Hotline Primo Primer or a shelf primer and let it dry completely before placing glass on the mold. This keeps the softened glass from bonding to the form. Reapply between firings as needed.

Specifications

• SKU: 3044
• Manufacturer: Bullseye Glass (design 8997, BG8997; slipcast by Creative Ceramics, Europe)
• Makes: square slumped dish with flat base
• Outer mold size: 5.2 x 5.2 x 1.3 in (13 x 13 x 3 cm)
• Note: molds are handmade and vary slightly in size; measure before cutting glass
• Material: slipcast ceramic kiln 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 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 shelf primer such as ZYP Boron Nitride Mold Primer and let it dry completely before placing glass on the mold.
• Cut your glass blank to fit the form. Measure your specific mold before cutting, since each mold is handmade and may vary slightly from the listed outer dimensions.
• Place the glass blank over the form on your kiln shelf. Fire slowly and confirm the slump visually during firing; remove heat once the glass has fully taken the form's shape.
• The mold is COE agnostic. Adjust the anneal soak for your glass: about 900 F for COE90 or 950 F for COE96.
• Let the kiln cool fully before removing the finished piece. Recoat the mold with kiln wash as needed between firings.

Bullseye Suggested Slumping Schedule

This is a suggested starting schedule for slumping 6mm glass in a Paragon GL24 kiln, based on Bullseye's guidance for design 8997. It is not a guarantee. Every kiln fires differently; follow Bullseye's published slumping guidance for your glass and mold, and test a small piece first.

• Segment 1 (ramp to slump): 300 F/hr to 1200 F, hold 10 minutes
• Segment 2 (anneal soak): AFAP (as fast as possible) to 900 F, hold 1 hour
• Segment 3 (anneal cool): 100 F/hr to 700 F, no hold
• Segment 4 (final cool): AFAP to room temperature, door closed, natural kiln cool

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

Description updated: July 6, 2026

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