Ingredients

Ingredient Amount
Gillespie Borate 30.00
Minspar 200 Feldspar 46.00
EPK Kaolin 13.00
Silica 11.00
Add Amount
Iron Chromate 0.50
Copper Carbonate 0.50

Instructions

This recipe was shared by Yoko Sekino-Bové in the December 2018 issue of Ceramics Monthly.
You can use any soda feldspar you have and and Gerstley Borate substitute, but always test first.