Underglaze Poster

What is the difference between glaze and underglaze?

Underglaze fires matte and is not sealed unless a clear glaze is applied and fired on top of it. Additionally, underglaze can be similar to a paint in that the fired color is similar to the color when fired. Glazes will melt and seal the piece without the use of a clear glaze and often fire to a very different color than when applied.

Does Speedball Underglaze stick to the kiln shelf when fired?

Due to several variable factors in ceramics, we recommend doing a test tile using your specific technique and clay body. Certain factors like temperature, clay body composition, and color can affect the firing properties of underglazes.

Are underglazes mixable?

Yes! You can mix the underglazes prior to applying to create your own custom colors, however we always recommend firing a test tile to ensure the final result is your desired shade.

What is the shelf life of Speedball glazes and underglazes?

Speedball glazes and underglazes have a shelf life of 2 years after manufacture, however when properly stored and maintained they can last much longer.

What temperature should I bisque to for Speedball glazes and underglazes?

We recommend bisquing to cone 05/04 for Speedball glazes and underglazes.

Can Speedball underglazes be high fired to cone 10?

Yes! Our unique formulation with strong pigments ensures several of our underglaze colors hold well at high temperatures. We recommend firing a test tile to ensure your clay body and process is compatible with your desired results.