Bullseye Glass Mold #8976, Heart Casting Mold 3.23"

The Heart Casting Mold from Bullseye Glass (design number 8976, model BG8976) casts a single glass heart, about 3.23 inches across, from frit or a glass blank loaded into the heart-shaped cavity. The mold is slipcast from a specially formulated clay body by Creative Ceramics in Europe and imported by Bullseye Glass. Its exceptionally smooth surface accepts kiln wash uniformly and holds up under repeated proper use.

The outer mold dimensions are 3.9 inches by 3.5 inches by 1.3 inches tall (10 x 9 x 3 cm), measured to help you check kiln fit. Because these molds are handmade they vary slightly in size, so measure your individual mold before cutting a glass blank to fit. Like all ceramic casting molds it is COE agnostic and reusable across many firings.

What does the Heart Casting Mold make?
It casts one small glass heart, about 3.23 inches across, from frit or a prepared glass blank fired to full fuse in the heart cavity.

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

How do I prep this mold before firing?
Coat the heart cavity with kiln wash or a boron nitride mold primer and let it dry completely before adding glass. The slipcast surface accepts kiln wash uniformly, so standard shelf primer works well.

What firing schedule does this casting mold use?
Bullseye's tip sheet schedule ramps 400 F per hour to 1225 F with a 1 hour hold, then 600 F per hour to 1490 F with a 10 minute hold, then drops as fast as possible to a 900 F anneal soak held for 2 hours. Always treat this as a starting point, match the schedule to your glass and kiln, and test a small run first.

Specifications

• SKU: 162948
• Manufacturer: Bullseye Glass (made by Creative Ceramics; model BG8976, design #8976)
• Makes: 1 cast glass heart
• Finished piece size: about 3.23 inches across
• Mold outer dimensions: 3.9 in L x 3.5 in W x 1.3 in H (10 x 9 x 3 cm)
• Material: slipcast ceramic (Creative Ceramics, imported by Bullseye Glass), 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 Bullseye's Heart Casting Mold tip sheet for your glass and kiln.

• Coat the heart cavity with kiln wash or a boron nitride mold primer such as ZYP Boron Nitride Mold Primer, and let it dry completely before adding glass so the finished piece releases cleanly.
• Fill the cavity with frit, small billets, or a cut glass blank, and fire to full fuse so the glass flows to fill the heart shape.
• The mold is COE agnostic. Use a firing schedule matched to your glass. Adjust the anneal soak temperature for your COE (about 900 F for COE90, about 950 F for COE96).
• Because these molds are handmade and vary slightly in size, measure your mold before cutting any glass blank intended to fit the cavity.
• Let the kiln cool fully before removing the cast piece. Recoat the mold with kiln wash or primer as needed between firings.

Bullseye Suggested Firing Schedule (Shallow Frit Cast)

This is a suggested starting schedule for a shallow frit cast, not a guarantee. Every kiln fires differently. Match the schedule to your glass thickness and kiln, follow Bullseye's Heart Casting Mold tip sheet, and test a small run first.

• Ramp 400 F per hour to 1225 F and hold 1 hour. (Fire gold-bearing styles with a 2 hour hold at 1225 F.)
• Ramp 600 F per hour to 1490 F and hold 10 minutes.
• Drop as fast as possible (AFAP) to 900 F and hold the anneal soak for 2 hours. (Adjust to about 950 F if using COE96.)
• Cool at 100 F per hour down to 800 F, then at 180 F per hour down to 700 F.
• Cool at 600 F per hour to room temperature.

Description updated: July 6, 2026

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