11/10/2025
White crackle Raku glaze information. I had realized that I was very late in responding to someone regarding non-Gerstly Borate Raku crackle glaze recipes. So I took a little time to respond and thought I'd share the information in case it's helpful to anyone other Raku potters who are followers. So here goes: GLAZE 1: Frit 3134 72.2, Nepheline 16.7, Tin Ox. 13, OM4, 5.5, silica 5.5 GLAZE 2: Frit 3124 90, and EPK 10 (apply thick) GLAZE 3: Frit 3110 47, Frit 3124 29, Lithium carb 12, silica,10, Bentonite 2. GLAZE 4: any high alkaline Frit 80, Nepheline syenite 20, Tin oxide 10. Personally, I use Gerstley Borate, which I have no issues with sourcing, where I live in Santa Rosa, CA
(Creative Ceramics and Glass). - I have always used Paul Soldner's original Gerstley 80, Nepheline 20 formula, and I particularly like the crackle I get from it. Also, Gerstley glazes can be brushed. Frit-based glazes are much harder to brush. I would either spray or dip Frit-based crackle glazes. Here are 2 additional recipes I have used as turquoise glazes, but simply omit the copper carbonate, and it is then a clear glaze. To have a nice white crackle, it's also important to use a clay that fires to a whiter bisque. I use a Laguna product called WSO (and always have used it as my Raku clay). Here are the 2 additional recipes that I have used for a turquoise crackle: Frit 3269 42.5, Frit 3134 27.5, Lithium carb 9.8, EPK 6.3, Silica 14, Bentonite 2, and for Turquoise, add Copper Carb 2.5 - 4 depending on the density of color desired. and lastly... Frit 3134 80, Nepheline 20, Tin 1, and for turquoise, add Copper Carbonate 2. (If I remember this glaze creates a large crackle rather than smaller, diverse crackles. With Frit glazes, I again would recommend spraying (best) or dipping. With some frit glazes, if you use a colorant, whether copper carbonate or stains, if you don't spray or dip, you can get uneven color on the vase. GOOD LUCK...Hope this helps.