An Introduction to Fusible Glass: What Temperature Do You Need?

Fusible glass — glass designed to be melted together in a kiln — opens up a completely different kind of studio work from ceramics. Here's what a beginner actually needs to know before starting a first project.

Fusing happens at a much lower temperature than you'd think

Compared to ceramic glaze firing (which can reach 2000°F or more), glass fusing happens at noticeably lower temperatures — generally in the range of 1300–1500°F, depending on the effect you want. A gentle "tack fuse" (where pieces stick together but keep some texture) uses a lower temperature than a "full fuse" (where everything melts into one smooth, flat surface).

The single most important rule: check your COE

Every type of fusible glass has a coefficient of expansion (COE) — essentially, how much it expands and contracts with heat. If you fuse together two glasses with different COE ratings, they cool at different rates and can crack, sometimes right out of the kiln. Always confirm that every piece of glass in a single project shares a compatible COE rating before you fuse them together — this matters more than color or brand.

Starting simple

A first project doesn't need to be complicated: a simple fused coaster or pendant using a couple of compatible sheet glass colors is a great way to get a feel for how glass moves and flows in the kiln before attempting anything more layered or sculptural.

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