Leaves on Saturated Iron Glaze
cone 10 oxidation
Firing profile
A two hour hold at 1850 deg F
A half hour hold at 1750 deg F
A three hour hold at 1700 deg F
slow downfire at 25 deg F an hour in the interval 1700 deg F to 1650 deg F
A half hour hold at 1650 deg F
Clay body is a grolleg porcelain from Tacoma Clay Art Center.
glaze composition
In the empirical formula:
alkali metals are respectively .84 and .77
Li2O is .23 in the both glazes
The remaining bases are divided between calcia and Magnesia,
with higher calcia
alumina is .63 in the first glaze, .46 in the second.
silica:Alumina ratio is ~6.3 in both glazes
alkali
metal:alumina ratio is 1.3 in the first, and 1.7 in the second.
The leaf print in the first glaze is intact, showing the veins and shape of
the original leaf.
The second glaze mangled the print.
The first glaze has higher alumina, and while it has higher total alkali
metals, it has a lower alkali metal : alumina ratio.
The first glaze, though it is a full gloss is a stiffer glaze, than the second.
The pots are pasta bowls ~12 inches in diameter.
glaze satIron_ZG_H_5
glaze satIron_ZG_H_1