Firing Saturated Iron Glazes
cone 10 oxidation with distinct downfire protocols
Firing #1 With slow downfire in two intervals
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
Firing #2 With long holds in two intervals
A three hour hold at 1850 deg F
One hour hold at 1650 deg F
Clay body is a grolleg porcelain from Tacoma Clay Art Center.
glaze composition
These glazes have high alkali metal, the numbers in the Empirical or Seger Formula:
Alkali metal ~.78
Li2O ~.2
molecular % silica ~64
The major difference is Alumina varies from .44 to .6
The pots are smll conical bowls ~3 inches in diameter.
glaze satIron_ZG_H_1
The result in Firing #1 with slow down ramps
The result in Firing #2 with long holds replacing slow down ramps
glaze satIron_ZG_0
The result in Firing #1 with slow down ramps
The result in Firing #2 with long holds replacing slow down ramps
glaze satIron_ZG_1
The result in Firing #1 with slow down ramps
The result in Firing #2 with long holds replacing slow down ramps