Bullseye Stiff Black Frit (style 000101) is 90 COE fusible frit, crushed glass in graded grain sizes for casting, layering, shading, and decorative surface work.
Cold characteristics Bullseye writes these notes for the sheet form of this color; the same glass is used to make this product.
Uniform color.
Working notes Stable. No color shift. Compared to Black (000100), Stiff Black (000101) has a slightly higher viscosity, meaning that it is a stiffer glass. In most kilnforming applications, Black and Stiff Black can be used interchangeably. Kilnforming applications where differences between Black & Stiff Black might be noticed include working with elevated drop ring molds and kilncasting. Stiff Black was originally developed for glass blowing purposes such as the Roll-up Technique. Using Stiff Black in kilnformed panels for this application creates a more uniform viscosity, which is easier to control.
Reactions This color is not reactive. It can sit next to any color without forming a reaction line, so it works well as a dependable base or background. See the Reactive Potential of Bullseye Glass chart to find the colors that do react.
Using the frit Bullseye frit is sold in grain sizes from powder to coarse. Powder gives soft, even color and shading, fine and medium build controlled texture and coverage, and coarse gives bold flecks of color and fills for casting and pattern bars. Choose the grain by the effect you want and the fired thickness of your piece.
Fusing and compatibility Tested compatible with other Bullseye glass. When you combine it with glass from other makers, matching COE alone does not guarantee compatibility, so fire a small test tile first.
More of This Color The same Bullseye color in other forms: 3mm Sheet · 2mm Thin Sheet · Stringers .
Helpful downloads What to Expect from Bullseye Glass (PDF)
Technical data courtesy of Bullseye Glass.
Description updated: July 7, 2026
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