Crystals in a non Iron Glaze
cone 10 oxidation
Firing profile
Up Fire profile
150 deg F an hour to 250 deg F
400 deg F an hour to 2050 deg F
120 deg F an hour to 2250 deg F
60 deg F an hour to 2290 deg F
40 deg F an hour to 2310 deg F with a hold of 10 minutes at 2310 deg F
Down Fire Profile
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 one hour hold at 1650 deg F
Clay body is a grolleg porcelain from Tacoma Clay Art Center.
The glaze satIron_ZG_Ip7_5, a saturated iron glaze with crystals was first seen here:
Here we see this glaze without the iron, but with what are apparently the same crystals.
glaze composition
This is a high alkali metal glaze containing P2O5, also 3 % Manganese Dioxide.
Emperical Formula satIron_ZG_Ip7_5MFe:
K2O 0.07
Na2O 0.43
Li2O 0.2
CaO 0.12
MgO 0.18
Al2O3 .71
SiO2 3.12
P2O5 .035
The visible individual crystals, ~ one quarter inch in diameter.
The pots is a conical bowls ~3 inches in diameter.
close up of crystals
glaze satIron_ZG_Ip7_5MFe