Ingredient Amount
Ferro Frit Fb-284-M 25.00
Custer Feldspar 75.00
Add Amount
Mason Stain 6.00


A body additive that can be wedged in to a clay body, which melts and swells during the firing.

Published in "Shigaraki Surfaces" by Elliott Kayser, in the Mar/Apr 2017 issue of Pottery Making Illustrated.
Add: 4–6% Mason Stain. I have tested the following colorants, used separately, with good results: 6% Mason stain 6027 Tangerine, 6% Mason stain 6304 Violet, 6% Mason stain 6404 Vanadium Yellow, 1% chrome oxide, 6% Mason stain 6021 Dark Red, and 1% cobalt carbonate. Add 37.5% water, mix and sinter fire to cone 05. Sinter fire the feldspar ingot in a bisque-fired crucible with lightly dusted alumina hydrate to prevent the feldspar from sticking.

After the feldspar ingot is fired, I remove it from the crucible, then smash it (wearing eye protection and heavy-duty gloves!) until I reach a desired chip size. I sieve out all the dust, otherwise the clay just looks contaminated. Once sieved, the feldspar chips can be wedged into the clay. By weight, I have been very happy with a 1:8 ratio of chips to clay in my sculptures.