Currie glaze tests in pursuit of cobalt greens, page 1
Glaze tests carried out using Ian Currie's grid method, as outlined in Revealing Glazes.
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Tiles were fired in a Skutt 1027-3 kiln with controller. Firing schedule was 50C/hr up to 120C, 150C/hr to 525C, 75C/hr to 600C, 150C/hr to 1050C, 60C/hr to 1200C, hold for 20 min. then cool at 200C/hr to 1000C, 100C/hr to 800C, hold for 45 min, then cool naturally from there.
To see the same glazes on the same clays, fired to cone 7 with a different schedule, see John Post's glaze test page
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Corner C= 100% Frit 3134, colorants are 3% cobalt carb, 5% rutile, clay is Highwater P5 porcelain, fired to 1200C
Close-up of top row, showing cobalt greens
Corner C= 100% Frit 3134, colorants are 3% cobalt carb, 5% rutile, clay is Highwater Speckled Brownstone, fired to 1200C
Close-up of top row, showing cobalt greens
Corner C= 100% Frit 3134, colorants are 3% cobalt carb, 5% rutile, clay is Highwater Speckled Brownstone, fired to 1200C
I was curious why we didn't see more greens on the first sets. Because my cobalt green glaze tends to be blue when it is applied too thickly, I tried applying the same 35 glazes, but more thinly. Bingo, more greens.
To see what would happen on a pot, I mixed together all the glazes in the top three rows, giving some approximation of glaze #8 in a quantity large enough to glaze a small bowl.
Glaze #8 applied thinly to small bowl (3" diameter). Very sensitive to application -- thinner areas inside the bowl are very dark, nearly black.
More Currie Grids in pursuit of cobalt greens
Currie grids by Kathy Greaves, Talc Set and Roy/Hesselberth Glossy Base Glaze 2
Currie grids by Debbie Engle, Talc Set on different clays