Currie glaze tests in pursuit of cobalt greens, page 3
Glaze tests carried out using Ian Currie's grid method, as outlined in Revealing Glazes.
Tiles were fired in a Skutt 1027-3 kiln with controller. Firing schedule was 80C/hr up to 120C, 150C/hr to 1050C, 60C/hr to 1200C, hold for 30 min. then cool at 200C/hr to 1000C, 80C/hr to 800C, hold for 45 min, then cool naturally from there. Note that this is a slightly different schedule than I used previously.
Click on tile images to see a larger version
The next set of experiments is going to involve adding other fluxes to the basic 3134 glaze, to see how this affects things. The following tiles show the effects of spodumene, wollastonite, strontium, and nepheline syenite/dolomite
Corner C= 90% Frit 3134, 10% Spodumene, colorants are 2% cobalt carb, 5% rutile, and 1.5% alumina oxide. Clay is Highwater Speckled Brownstone, fired to 1200C
Corner C= 90% Frit 3134, 10% Wollastonite, colorants are 2% cobalt carb, 5% rutile, and 1.5% alumina oxide. Clay is Highwater P5 porcelain, fired to 1200C
As you can see, the wollastonite seems to have killed the greens.
Is it the additional flux, or the fact that wollastonite is contributing more silica?
Corner C= 90% Frit 3134, 10% Wollastonite, colorants are 2% cobalt carb, 5% rutile, and 1.5% alumina oxide. Clay is Highwater Speckled Brownstone, fired to 1200C
Coming soon: Corner C= 90% Frit 3134, 10% Strontium, colorants are 2% cobalt carb, 5% rutile, and 1.5% alumina oxide. Clay is Highwater P5 porcelain, fired to 1200C
Corner C= 90% Frit 3134, 10% Strontium, colorants are 2% cobalt carb, 5% rutile, and 1.5% alumina oxide. Clay is Highwater Speckled Brownstone, fired to 1200C
Coming soon: Corner C= 90% Frit 3134, 5% Nepheline Syenite, 5% Dolomite, colorants are 2% cobalt carb, 5% rutile, and 1.5% alumina oxide. Clay is Highwater Speckled Brownstone, fired to 1200C
Cobalt Greens, page 2
Back to first set of Currie grids, thumbnail version
Currie grids by John Post
Currie grids by Kathy Greaves, thumbnail version
Currie grids by Debbie Engle, thumbnail version