Leopard Spots
The glaze satIron_ZG_Z3N_EPK seen as the second glaze
here developed leopard spots.
So then I wondered, "what else is nearby?", And this glaze, shown here,
satIron_ZG_Z3N_Z3T, resulted.
The glaze satIron_ZG_Z3N_Z3T has slightly lower silica:alumina ratio as a
consequence of lower silica
These spots are the artifact left behind by bubbles popping in the glaze at a
point in the firing late
plate is ~ 7 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 2 hour hold at 1850 deg F
300 deg F an hour to 1750 deg F then a 1 hour hold at 1750 deg F
300 deg F an hour to 1700 deg F then a 3 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 0.12
Al2O3 0.75
SiO2 3.51
molecular percent Silica 63%
K2O 0.43
Al2O3 0.54
SiO2 3.33
molecular percent Silica 48%
A leaf is softened by soaking in water laced with trisodium phosphate. After
the pot is glazed, the leaf is pressed
and higher alumina. It also has higher MgO, to
which I attribute the denser leopard spots,
enough that they are not ironed out by further
chemical reactions within the glaze.
Image of the plate with glaze satIron_ZG_Z3N_Z3T and leaf wash
leaf_Z3K.
oxidation firing to cone 10 in an electric kiln
Firing profiles
Up Fire profile
Down Fire Profile
Clay body is a grolleg porcelain from Clay Art Center in Tacoma, WA.
glaze compositions
Empirical Formula satIron_ZG_Z3N_Z3T:
Na2O 0.53
CaO 0.28
MgO 0.07
Fe2O3 0.23
P2O5 0.07
Empirical Formulae of leaf wash glaze leaf_Z3K:
Na2O 0.53
CaO 0.04
P2O5 0.15
into the glaze. When the glaze
dries, a swatch of plate including the leaf is coated with wax. When the wax
is dry, the leaf is removed and the indentations in the glaze are coated
with a very thin layer of an
underfired glaze.