Rectangle Box and Lid

The Rectangle Box and Lid mold set from Colour de Verre is a two-piece ceramic casting system that produces a complete fused glass box. One mold forms the rectangular base and the other forms the matching lid, so both pieces are cast separately and can be coordinated from the start. The base mold measures 5.75 inches by 6.5 inches by 2.37 inches deep and calls for about 450 grams of glass. The lid mold takes about 220 grams.

Fill the cavities with frit of any mesh size, billets, casting rocks, pebbles, nuggets, nipped rods, or sheet glass. After the initial casting firing, you can personalize the box in a second firing by tack fusing additional Colour de Verre castings such as blossoms, pine cones, leaves, butterflies, dragonflies, or scarabs to the surface. The finished piece is suited to decorative keepsake boxes, gifts, or functional art. Like all ceramic casting molds, these are COE agnostic and reusable across many firings with proper preparation.

What does the Rectangle Box and Lid mold set make?
It casts two pieces, a rectangular box base and a matching lid, which are fired separately and assembled into a finished glass box. The base mold is 5.75 x 6.5 x 2.37 inches deep.

What glass can I use in these molds?
Any COE. Ceramic casting molds are COE agnostic, so the same molds work with COE96, COE90, or other fusible glass. Match your firing schedule to the glass you are using.

How much glass do I need per mold?
Colour de Verre lists about 450 grams for the base cavity and about 220 grams for the lid cavity. You can fill with frit of any mesh, billets, casting rocks, pebbles, nuggets, nipped rods, or sheet glass.

Can I decorate the finished box after casting?
Yes. In a second firing you can tack fuse additional Colour de Verre castings, such as blossoms, pine cones, leaves, butterflies, dragonflies, or scarabs, onto the box to personalize it.

How do I prep the molds before casting?
Prime all cavities with a dedicated mold primer such as ZYP BN Lubricoat or Hotline Primo Primer before every use. Let the primer dry completely before adding glass so the cast pieces release cleanly.

Specifications

• SKU: 181650
• Manufacturer: Colour de Verre
• Makes: one rectangle box base and one matching lid (two-mold set, fired separately)
• Base mold size: 5.75 inches L x 6.5 inches W x 2.37 inches deep
• Fill weight (base): about 450 grams
• Fill weight (lid): about 220 grams
• Material: ceramic kiln casting molds, 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.

• Prime both mold cavities with a dedicated mold primer before every use. Colour de Verre recommends ZYP Boron Nitride Mold Primer or Hotline Primo Primer. Let the primer dry completely before adding glass.
• Fill the base cavity with about 450 grams of glass and the lid cavity with about 220 grams. Use frit of any mesh, billets, casting rocks, pebbles, nuggets, nipped rods, or sheet glass.
• The molds are COE agnostic. Use a firing schedule matched to your specific glass.
• For a second decorative firing, tack fuse Colour de Verre castings such as blossoms, leaves, or butterflies onto the box surface.
• Let the kiln cool fully before removing the cast pieces. Prime the molds again before each subsequent 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.

• Prime the mold cavities before every use and let the primer dry completely.
• 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 matched to your glass.

Helpful downloads: Priming Molds With ZYP Spray (PDF)

Description updated: July 6, 2026

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