The Small Butterflies with Slumper mold from Colour de Verre casts two glass butterflies with different wing designs in a single firing. The small butterfly takes about 28 grams of frit and the large takes about 32 grams, and both finish at approximately 3 inches (7.5 cm) across. Two distinct sizes in one run makes this a practical mold for building a supply of butterfly pieces for jewelry, mosaic work, or larger mixed-media projects.
A feature that sets this mold apart is the integrated wing slumper built into its reverse side. After the butterflies are cast flat, you can place them on the slumper side and fire a second time to add natural curvature to the wings, giving the finished pieces a more lifelike, three-dimensional look. Like all ceramic casting molds, it is COE agnostic and reusable across many firings when primed properly before each use.
What does the Small Butterflies with Slumper mold make?
It casts two butterflies in one firing: one small, using about 28 grams of glass, and one large, using about 32 grams. Both finish at approximately 3 inches (7.5 cm) across. The reverse side of the mold includes a built-in wing slumper for adding curvature in a second firing.
How does the integrated wing slumper work?
After casting the butterflies flat, place them on the reverse slumper side of the mold and fire a second time at a lower temperature. This curves the wings and gives the pieces a more natural, three-dimensional shape.
How much glass do I need per cavity?
Colour de Verre lists about 28 grams for the small butterfly and about 32 grams for the large. Weigh your glass and test a first run, since fill weight can vary with how frit is packed and the result you are after.
What COE glass can I use in this mold?
Any COE. Ceramic casting molds are COE agnostic, so the same mold works with COE96, COE90, or other fusible glass. Match your firing schedule to the specific glass you are using.
How do I prepare the mold before firing?
Colour de Verre specifies priming the mold before every use. Apply a boron nitride or compatible primer to the cavities and let it dry fully before adding glass, so the cast pieces release cleanly.
Specifications
- SKU: 181432
- Manufacturer: Colour de Verre
- Makes: 2 butterflies (small and large) per firing
- Finished piece size: approximately 3 inches (7.5 cm) each
- Fill weight: about 28 grams (small), about 32 grams (large)
- Feature: integrated wing slumper on reverse side
- Material: ceramic kiln casting mold, 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 the Colour de Verre project sheet for this mold.
- Colour de Verre requires priming the mold before every use. Apply ZYP Boron Nitride Mold Primer or Hotline Primo Primer to the cavities and let it dry completely before adding glass.
- Fill the small butterfly cavity with about 28 grams of frit and the large cavity with about 32 grams. You can use frit, crushed glass, or a mix suited to your project.
- The mold is COE agnostic. Use a full fuse schedule matched to your glass.
- To add curvature to the wings after casting, place the flat butterflies on the reverse slumper side of the mold and fire a second time at a slump temperature suited to your glass.
- Let the kiln cool fully before removing the pieces. Prime the mold again before the next firing.
Colour de Verre Suggested Firing Schedule
This is a suggested starting schedule, not a guarantee. Every kiln fires differently. Follow the Colour de Verre project sheet for this mold and test a small run first before committing to a full batch.
- Heat no faster than about 350 F (195 C) per hour.
- Fire to no more than about 1450 F (785 C).
- Add a controlled cool with an anneal soak appropriate for your glass and the COE you are using.
Helpful downloads: Embellished Photo Frames (PDF) · Small Dragonflies Tutorial (PDF) · Tips for Thin Casting (PDF) · Tricks of the Trade (PDF) · Priming with ZYP Spray (PDF)
Description updated: July 6, 2026
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