High Alumina Orange
firing to cone 10 in oxidation
A half hour hold at 1850 deg F
slow downfire at 50 deg F an hour in the interval 1850 deg F to 1700 deg F
slow downfire at 25 deg F an hour in the interval 1700 deg F to 1650 deg F
One hour hold at 1650 deg F
Clay body is a grolleg porcelain from Tacoma Clay Art Center.
glaze composition
The bases in this glaze are alkali metals with Li2O .77. Alkaline earths are at the level of impurities.Alumina is 1.5, Silica is 5.1, and Fe2O3 .04.
I'd been curious about the white streaking which follows
the glaze application pour marks,
and had thought that excess unincorporated
alumina hydroxide was the cause.
This glaze contains no Alumina
Hydroxide.
Note the dark orange brown at the bottom of the deap pinholes.
The iron in this glaze is added in the batch, yet we observe with the
deaply colored pinholes,
the white streaking and also the mottled orange on
the rim, the iron migration within this glaze.
The pot is a small conical bowls ~3 inches in diameter. We show the inside and outside of the bowl.
glaze sh_ZH_1
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