Bullseye Glass Mold #8943, Cone Bowl 7.4" x 2.2"

The Cone Bowl mold from Bullseye Glass (design #8943) is a steep-sided slumping form that shapes a flat glass blank into a narrow cone bowl. The outer dimensions are 7.4 inches by 2.2 inches (19 by 6 cm); confirm those measurements against your kiln before cutting glass. Because these molds are handmade by Creative Ceramics from a specially formulated clay body, individual pieces vary slightly in size.

The clay body produces an exceptionally smooth forming surface that accepts kiln wash uniformly and does not crack under repeated proper use. Like all ceramic slumping molds, it is COE agnostic, so it works with COE90, COE96, or other compatible fusible glass. Match your firing schedule and anneal soak temperature to the glass you are using.

What does the Cone Bowl mold make?
It slumps a flat glass sheet or fused blank into a steep-sided cone bowl. The glass softens and settles into the narrow, tapered form by gravity as it heats in the kiln.

How do I cut the glass to fit?
Cut the glass to the diameter of the top rim, or up to 1/16 inch (about 1.5 mm) larger all around. The narrow rim at the top of the cone supports the glass as it softens and slides down into the form.

What COE glass can I use?
Any COE. Ceramic molds are COE agnostic, so the same mold works with COE90, COE96, or other fusible glass. Use a slumping schedule suited to your glass and adjust the anneal soak accordingly.

How do I set up the mold in the kiln?
Elevate the mold on 2 inch (5 cm) posts and center it in the kiln. Level both the mold and the glass before firing to promote even heating, slumping, and cooling.

How often do I need to re-prime the mold?
Because of the steep cone geometry, Bullseye recommends re-priming the forming surface every 2 to 3 firings rather than after every single firing. Apply kiln wash uniformly and let it dry fully before loading glass.

Specifications

• SKU: 7746
• Manufacturer: Bullseye Glass (BG8943; design #8943; item 008943-MOLD-M-EACH), made by Creative Ceramics in Europe
• Makes: steep cone bowl (slumping mold)
• Outer mold dimensions: 7.4 in x 2.2 in (19 x 6 cm)
• Glass cut size: diameter of the top rim, or up to 1/16 in (1.5 mm) larger all around
• Kiln setup: elevate on 2 in (5 cm) posts, centered and level
• Re-prime interval: every 2 to 3 firings
• Material: slipcast ceramic, handmade by Creative Ceramics (individual sizes vary slightly)
• 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.

• These molds are handmade and vary slightly in size. Measure the mold before cutting glass to ensure a good fit.
• Prime the forming surface with kiln wash or a boron nitride primer such as ZYP Boron Nitride Mold Primer, and let it dry fully before loading glass.
• Because of the steep cone geometry, re-prime the forming surface every 2 to 3 firings rather than after every single firing.
• Elevate the mold on 2 inch (5 cm) posts, centered and level in the kiln, to promote even heating, slumping, and cooling.
• Cut glass to the diameter of the top rim, or up to 1/16 inch (about 1.5 mm) larger all around, so the rim supports the glass as it softens into the form.
• The mold is COE agnostic. Adjust the anneal soak for your glass: about 900 F for COE90, about 950 F for COE96.

Suggested Slumping Schedule (Cone Bowl)

This is a suggested starting schedule based on Bullseye's published guidance for steep cone slumps. It is not a guarantee. Every kiln fires differently. Follow Bullseye's Cone Bowl tip sheet for your glass, visually confirm the slump is complete before ending the process hold, and test a small piece first.

• Ramp at 300 F per hour to 1200 F and hold for 30 minutes. Bullseye uses this lower temperature hold to begin the slump and promote a uniform drop into the steep form.
• Ramp at 300 F per hour to 1225 F and hold for about 1 hour 30 minutes, longer than a shallow form needs, to let the glass settle fully into the steep cone. Visually confirm the slump is complete before ending the hold.
• Cool as fast as possible (AFAP) down to the anneal soak temperature: about 900 F for COE90, about 950 F for COE96.
• Hold at the anneal soak for about 1 hour.
• Cool at 100 F per hour from the anneal soak down to 700 F.
• Cool as fast as possible (AFAP) from 700 F to room temperature.

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

Description updated: July 6, 2026

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