Bullseye Glass Mold #8901, Square Plate, Simple Curve Slumper 3.3"

The Bullseye Glass Mold #8901 is a compact square plate slumper that forms a shallow simple curve in a 3.3 inch square piece of glass. A pre-cut blank or fused piece is placed on the form and heated in the kiln until the glass softens and settles around the curve by gravity. The finished result is a small square plate with a smooth, even shallow bow, suited to dishes, small trays, jewelry components, or accent pieces.

The mold is slipcast from a specially formulated clay body by Creative Ceramics in Europe and imported and sold by Bullseye Glass. The surface is exceptionally smooth and accepts kiln wash uniformly, making prep straightforward. The outer dimensions are 3.3 by 3.3 by 0.8 inches (8 by 8 by 2 cm), useful for checking kiln shelf fit. Because these molds are handmade, individual pieces vary slightly in size, so measure your specific mold before cutting glass. Like all ceramic slumping forms, this mold is COE agnostic and reusable across many firings with proper care.

What does Bullseye mold #8901 make?
It slumps a glass blank into a small square plate with a shallow simple curve. The outer mold dimensions are 3.3 inches square, but because these molds are handmade and vary slightly, measure your specific mold before cutting the blank.

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

How do I prep this 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. The smooth slipcast surface accepts kiln wash uniformly. Re-coat as needed between firings.

How do I cut and place the glass?
Measure your specific mold before cutting the blank, since these handmade molds vary slightly in size. Place the cut blank flat on the coated forming surface, center it, and fire. Visually confirm the slump during firing if your kiln allows.

Specifications

• SKU: 3660
• Manufacturer: Bullseye Glass (design #8901, store code BG8901; slipcast by Creative Ceramics in Europe, imported by Bullseye)
• Makes: one square plate with a shallow simple curve
• Finished piece size: approximately 3.3 inches square (based on outer mold dimensions; measure your mold before cutting glass)
• Mold outer dimensions: 3.3 x 3.3 x 0.8 in (8 x 8 x 2 cm)
• Note: molds are handmade and vary slightly in size
• 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 run 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 so the finished piece releases cleanly after firing.
• Measure your specific mold before cutting the blank. These molds are handmade and vary slightly in size, so cut to fit what you have in hand.
• Place the blank flat on the coated mold surface. Visually confirm the slump during firing if your kiln allows, and remove the piece once it has settled fully to the curve.
• The mold is COE agnostic. Use a slumping schedule matched to your glass, adjusting the anneal soak temperature for your COE.
• Let the kiln cool fully before removing the slumped piece. Re-coat the mold with kiln wash or primer as needed between firings.

Bullseye Suggested Slumping Schedule

This is a suggested starting schedule based on Bullseye's published guidance for slumping 6mm pieces in a Paragon GL24 kiln, 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.

Hold times are in H:MM format (1:30 = 90 minutes, 1:00 = 60 minutes). AFAP means as fast as possible, letting the kiln cool at its natural rate with the door closed. Segment 2 anneal soak is shown at 900 F, suited to Bullseye COE90 glass. If using COE96, adjust the anneal soak temperature to 950 F.

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

Description updated: July 6, 2026

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