Bullseye Glass Mold #8948, Pyramid Casting Mold 6.7"

The Pyramid Casting Mold from Bullseye Glass (design number 8948, store model BG8948) is a ceramic casting mold that produces a solid glass pyramid in a single firing. Frit, crushed glass, or billets are loaded directly into the mold cavity, and the glass melts and flows into the pyramid form as the kiln heats. At a full fill of about 2090 g (4.6 lb), the finished pyramid stands 3.75 inches (9.5 cm) tall. A lighter fill of about 150 g produces a smaller pyramid roughly 1.8 inches (4.6 cm) tall, so the same mold gives you a range of finished heights.

The mold is slipcast from a specially formulated clay body by Creative Ceramics in Europe and imported by Bullseye Glass. The outer dimensions are 6.7 x 6.7 x 4.7 inches (17 x 17 x 12 cm), which is the measurement to check against your kiln shelf. Because these molds are handmade, individual pieces vary slightly in size, so measure your mold before cutting any supporting pieces. The surface accepts kiln wash uniformly and does not crack under repeated proper use. As a ceramic casting mold it is COE agnostic and reusable across many firings.

What does the Pyramid Casting Mold make?
It casts one solid glass pyramid per firing. At a full fill the finished pyramid is about 3.75 inches (9.5 cm) tall. A light fill of about 150 g produces a smaller pyramid roughly 1.8 inches (4.6 cm) tall.

How much glass do I need?
Bullseye lists about 2090 g (4.6 lb) for a full 3.75 inch pyramid and about 150 g for a smaller 1.8 inch pyramid. Fill weight determines the finished height, so weigh your glass and test a first run when the result matters.

What type of glass can I use?
Any form of fusible glass works, including frit and billets. The form you choose affects the clarity of the finished casting. The mold is COE agnostic, so it works with Bullseye glass or other compatible fusible glass; match your firing schedule to the glass you are using.

How do I prep the mold before casting?
Coat the interior surface of the mold with a kiln wash such as Hotline Primo Primer and let it dry fully before loading glass. You may also use a boron nitride mold primer. Bullseye specifies this mold must be re-prepared before every casting firing: buff away the fired separator, then re-apply before loading glass.

Specifications

• SKU: 7749
• Manufacturer: Bullseye Glass (model BG8948, design #8948, item 008948-MOLD-M-EACH)
• Makes: 1 solid glass pyramid per firing
• Finished piece size: up to 3.75 in (9.5 cm) tall at full fill; about 1.8 in (4.6 cm) tall at light fill
• Outer mold dimensions: 6.7 x 6.7 x 4.7 in (17 x 17 x 12 cm); handmade, measure before cutting
• Fill weight: about 2090 g (4.6 lb) for full pyramid; about 150 g for smaller pyramid
• Material: ceramic casting mold, slipcast from a specially formulated clay body, made by Creative Ceramics in Europe, imported by Bullseye Glass; reusable
• Glass: any COE (COE agnostic); frit or billet

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 casting schedule suited to your glass and kiln.

• Coat the interior surface of the mold with kiln wash and let it dry completely before loading glass. You may also use a boron nitride mold primer such as ZYP Boron Nitride Mold Primer. Bullseye specifies this mold must be re-prepared before every casting firing: buff away the fired separator (a nylon bristle brush for fired ZYP, a dry scrub pad for fired shelf primer), then re-apply before loading glass.
• Fill with frit, crushed glass, or billets. The form of glass chosen affects the clarity of the finished pyramid; billets and larger pieces tend to produce clearer results.
• The mold is COE agnostic. Match your firing and annealing schedule to the glass you are using.
• This is a thick casting. A full pyramid at 3.75 inches requires a long, carefully controlled anneal. Follow Bullseye's Annealing Thick Slabs chart for your finished casting thickness.
• Let the kiln cool fully to room temperature before removing the casting.

Suggested Casting Schedule (Bullseye Starting Point)

This is a suggested starting schedule based on Bullseye's guidance for this mold, not a guarantee. Every kiln fires differently. Follow Bullseye's Pyramid Casting Mold tip sheet and Annealing Thick Slabs chart for your casting thickness, and test first.

• Ramp to a process soak of about 1525 F and hold for about 2 hours for a full cast.
• Cool as fast as possible (AFAP) down to 900 F and hold for 8 hours. This 8 hour anneal soak at 900 F is part of Bullseye's published schedule for a full-thickness cast.
• From 900 F, follow a slow, controlled anneal cool per Bullseye's Annealing Thick Slabs chart for your finished casting thickness. Bullseye's published full-cast schedule follows a 2 inch (50 mm) anneal profile; for a smaller fill of about 150 g, modify to a 1 inch (25 mm) anneal per the chart.
• Continue the controlled cool all the way to room temperature before opening the kiln.

Description updated: July 6, 2026

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