Orange Glaze
A Glaze on porcelain colored by impurities.
Whence the distinct speckled orange of this glaze?
The only iron in the glaze is that contributed as impurities by the feldspars
and kaolin. This glaze is fired on a
bowl is ~ 4 inches in diameter.
150 deg F an hour to 250 deg F
400 deg F an hour to 1800 deg F
300 deg F an hour to 2050 deg F
120 deg F an hour to 2310 deg F with a hold of 20 minutes at 2310 deg F
300 deg F an hour to 1850 deg F then a two hour hold at 1850 deg F
300 deg F an hour to 1750 deg F then a one hour hold at 1750 deg F
300 deg F an hour to 1700 deg F then a three hour hold at 1700 deg F
25 deg F an hour to 1650 deg F then a one hour hold at 1650 deg F
K2O 0.19
Al2O3 0.70
SiO2 2.98
molecular percent Silica 62.9%
porcelain body, so is not absorbing iron
out of the body on which it is fired. Perhaps the low silica:alumina ratio is
relevant.
Other glazes in the same glaze family have higher silica with
correspondingly higher silica:alumina ratio,
and are enamel white. Shino
glazes usually have a low silica alumina ratio and capture stunning oranges
with little iron.
Image of the glaze jingdezhen-Z3L-PEPK-MAlkSi
inside
outside
oxidation firing to cone 10 in an electric kiln
Firing profiles
Up Fire profile
Down Fire Profile
Clay body is a grolleg porcelain from Tacoma Clay Art Center.
glaze composition
Empirical Formula jingdezhen-Z3L-PEPK-MAlkSi:
Na2O 0.21
CaO 0.30
MgO 0.30
Fe2O3 0.005
P2O5 0.04