An Iron Impurity Orange Glaze
This glaze, sIron_MFe_Z3A_1, containing no added iron and fired on a porcelain body becomes a pale, opaque orange.
The amount of iron required to produce a color of a particular saturation is
determined by the composition of the glaze.
I've seen saturated iron glazes
with between .1 molecular equivalents, and .3 molecular equivalents.
At the other end of the scale, how little iron does it take to color a glaze?
Celadon glazes with .01 molecular
equivalents of iron are common.
This is the strongest color I've seen in an opaque glaze, on a non
iron-bearing clay body, with 0.007
molecular equivalents of iron.
Image of the glaze sIron_MFe_Z3A_1
inside
outside
bowl is ~ 3.5 inches in diameter
oxidation firing to cone 10 in an electric kiln
Firing profiles
Up Fire profile
150 deg F an hour to 250 deg F
400 deg F an hour to 2050 deg F then a hold of 20 min
120 deg F an hour to 2310 deg F with a hold of 20 minutes at 2310 deg F
Down Fire Profile
300 deg F an hour to 2210 deg F then a one hour hold at 2210 deg F
80 deg F an hour to 1900 deg F
300 deg F an hour to 1750 deg F then a half hour hold at 1750 deg F
300 deg F an hour to 1700 deg F then a Two hour hold at 1700 deg F
300 deg F an hour to 1600 deg F then a Two hour hold at 1600 deg F
Clay body is a grolleg porcelain from Tacoma Clay Art Center.
glaze composition
Empirical Formula sIron_MFe_Z3A_1 :
K2O 0.06
Na2O 0.02
Li2O 0.15
CaO 0.44
MgO 0.11
SrO 0.22
Al2O3 0.49
Fe2O3 0.007
SiO2 2.73
P2O5 0.12
TiO2 0.01
molecular percent Silica 62.5%