Bullseye Stiff Black Stringers (style 000101) are 90 COE fusible stringers, thin rods of glass for drawing fine lines, outlines, and linear detail on fused 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 stringers Stringers are thin, uniform rods you lay on the surface to draw lines, borders, lettering, and fine detail. They fuse flat into the glass and can be snipped, bent with a little heat, or arranged into patterns before firing.
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 · Frit .
Helpful downloads What to Expect from Bullseye Glass (PDF)
Technical data courtesy of Bullseye Glass.
Description updated: July 7, 2026
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