Spectrum 536 Bright Blue Opaque Underglaze Size:4 oz The most effective opacifier

The most effective opacifier

For creating

and becomes a deep lilac color and begins to burn out at cone 10

That means that it's presence enables reducing feldspar content which in turn provides even more opportunity to source Al2O3 from kaolin or clay

Keep unused clay in a plastic bag or wrapped in damp cloth to prevent drying out

Spectrum 536 Bright Blue Opaque Underglaze Size:4 oz The most effective opacifierFor use on clay or greenware: apply one, two or three coats and let dry and bisque fire to shelf cone 04. If desired, apply a clear or colored translucent glaze and fire to cone 06. For use on bisque: apply one, two or three coats and let dry. Apply a clear or other colored translucent glaze and fire to cone 06. The samples shown are fired to cone 05 but can be fired to low temperature (cone 06 04) to high temperature (cone 9 10). Some color variation