COE90 Sheet Glass

COE90 sheet glass is fusing-compatible art glass formulated to a coefficient of expansion of 90 for kilnforming, slumping, casting, and panel work. The COE90 selection at Art Glass Supplies is dedicated Bullseye Glass Company sheet, covering double-rolled 3mm and thin-rolled 2mm in opalescent and transparent palettes, along with iridescent finishes, streakies, collage sheets, and Special Production runs.

What COE90 Sheet Glass Is

COE90 describes glass made to a 90 coefficient of expansion so compatible sheet, frit, stringer, and other components are intended to heat and cool together with reduced compatibility risk when fired on an appropriate schedule. Every sheet in this category is Bullseye, which keeps it inside the Bullseye fusing system from base layer to surface accent. Use COE90 sheet for full fuse, tack fuse, slump, drape, kiln carving, pot melts, and stained glass panels you plan to fire rather than lead.

What is in this Category

Bullseye sheet here is sorted by surface, thickness, and finish. Opalescent 3mm and Transparent 3mm double-rolled sheets are the workhorses for single-layer cuts and the base of a two-layer fused stack. Opalescent Thin-Rolled 2mm and Transparent Thin-Rolled 2mm are useful for overlays, detail work, lighter layers, and controlled color stacking. Iridescent sheet adds rainbow, silver, gold, and silver-to-bronze finishes over transparent or opalescent bases. Streakies blend two or more colors into one sheet, and Collage sheets carry fractures and streamers across clear or lacy white grounds. Special Production covers limited drizzles, stripes, and aventurine combinations.

Choosing Thickness and Finish

Reach for 3mm double-rolled when you want a single full-thickness layer or the bottom of a 6mm fused stack. Choose thin-rolled 2mm when you want finer layering control, overlays, aperture pours, pattern bars, or detail cuts. If a project needs a 6mm full-fuse thickness, build the stack with enough compatible COE90 glass to reach that target. Iridescent sheet can be fired iridescent side up for a metallic shimmer, or capped with clear and fired iridescent side down for a softer shift under the glass.

Firing and Compatibility Notes

Keep COE90 with COE90 throughout any single firing. Mixing COE90 with COE96, float/window glass, bottle glass, or other untested glass can cause stress and cracking as the piece cools. Bullseye sheet is designed to be compatible across the Bullseye line, so opalescent, transparent, iridescent, streaky, collage, and Special Production sheets are made to fuse together within the Bullseye-compatible COE90 system, though testing is recommended when appearance or compatibility is critical. Run a schedule sized to your kiln load and target thickness, and follow the published Bullseye anneal soak for full thickness work.

Project Uses

COE90 sheet covers fused jewelry, slumped bowls and sushi plates, kiln-carved tiles, pattern bars, murrine pulls, and panels intended for the kiln. Opalescent reads as solid color in transmitted light, transparent glows, iridescent shifts color with the viewing angle, and streaky and collage sheets bring built-in movement without extra layering.