Glass fusing creates permanently bonded glass compositions, but the range of surface effects you can achieve depends heavily on what you fire and how. From ultra-smooth fire polish to textured, dimensional surfaces, the firing temperature and schedule are the levers that control outcome. Here's a practical breakdown of the main surface effects and how to achieve them.
A full fire polish happens when glass is heated just above its softening point (roughly 1350°F–1450°F) long enough for surface tension to smooth out any texture, scratches, or cut edges. The result is a glossy, liquid-smooth surface that looks and feels like polished glass — without any grinding or polishing work.
Fire polishing is useful for finishing cut edges, recovering surface damage, and giving a professional finish to functional pieces. The key is staying below full fuse temperature — you want to smooth the surface without moving the glass enough to lose its shape or thickness.
A tack fuse fires to a temperature where separate glass pieces bond together but don't flow flat (roughly 1350°F–1425°F). The edges of layered pieces retain their original shape — you can see where one piece ends and another begins. This creates dimensional, textured effects that a full fuse would flatten.
Tack fusing is popular for frit work, dichroic layering, and any technique where preserving the edge definition of individual elements matters. It's also useful for first-firing complex assembled pieces that need structural bonding before a final full fuse.
A full fuse fires to 1480°F–1520°F and holds long enough for all layered glass to flow flat and merge into a single unified piece. Cut edges round over, separate pieces flow together, and the surface develops a characteristic fire-polished smoothness. The finished piece will be approximately 6mm thick regardless of how many layers you started with (Bullseye's standard for fused glass is two layers of 3mm).
Full fuse is the starting point for most slumping work — you full-fuse your blank, anneal, let it cool, then slump in a second firing.
Kiln shelves, fiber paper, and ceramic texture tiles can all be used to imprint texture onto the underside of fused glass during firing. Fired against textured ceramic fiber paper, glass picks up a matte, sandblasted-looking surface on one side. Fired against a stainless mesh shelf, glass can pick up a grid texture.
Texture firing requires kiln wash or separator between the glass and the texture surface — even if the texture material is described as non-stick. Test every new combination before committing a finished piece.
The difference between a tack fuse and a full fuse is often 50–100°F and a few minutes of hold time. Getting repeatable results requires a well-calibrated oven with a reliable controller and a consistent firing schedule. The Hot Shot 12G and Hot Shot 16G are designed for exactly this kind of precision — tight temperature control, even heat distribution, and programmable multi-segment schedules.
Keep a firing log. Note temperature, hold time, glass type, and the results you got. After 20–30 firings, you'll have a personal reference that tells you exactly how your kiln and your glass interact — which is more useful than any general guide.
Browse our glass kiln lineup or reach out if you have questions about firing schedules for a specific project.
{"one"=>"Select 2 or 3 items to compare", "other"=>"{{ count }} of 3 items selected"}