COE90

COE90 glass is fusing glass made to a coefficient of expansion of 90, the compatibility system built around Bullseye Glass Company. Art Glass Supplies stocks the whole COE90 system in one place, so a project can go from base sheet to finishing accents without ever leaving compatible glass.

What's in this category at AGS

The COE90 range covers Sheet Glass in Bullseye opalescent, transparent, iridescent, and streaky styles, Dichroic Glass from CBS in patterned and solid color coatings, and Glass Packs that bundle coordinated colors. For detail and surface work there are Frit in graded sizes, Confetti shards, Murrini and Millefiore slices, Stringers, Twisted Cane, Ribbons, and Dots. Precut Shapes offer ready-to-fire blanks for jewelry and ornament work.

Why COE matters

Coefficient of expansion describes how much a glass expands as it heats. For a fused piece to survive firing without stress cracks, every glass in the piece should share the same COE. COE90 and COE96 are the two most common systems, and they are never mixed in one project. Same-COE glass is designed to expand and contract together, and Bullseye tests its glass for compatibility within the 90 system.

Shopping the COE90 system at Art Glass Supplies

Start with sheet glass for the body of the piece, add dichroic where you want reflective color shift, and finish with frit, stringers, murrini, or dots for line work and detail. Because these ranges are Bullseye and Bullseye-compatible 90 COE, components can be combined in the same firing; when you add glass from other makers, test compatibility first. If you work in the other system, see our COE96 section instead.