Increased Iron
Two glazes, nearly twins, except for the difference in iron.
The first glaze, iron_Alex_0, is a gorgeous glaze with metallic acicular
crystals, yet so fluid that on a
The second glaze, iron_Alex_si, moves little, and if at all thick, has a
background which is a textured
Both glazes have largish acicular crystals on a tortoise shell ground, yet the
appearance of the
The greatest difference in the composition of these two glazes is that
iron_Alex_0 contains a third more
The glare in the image of iron_Alex_0 near the upper left creates the illusion
that the glaze is chipped;
bowl is ~ 4 inches in diameter.
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 1800 deg F then a 2 hr hold at 1800 deg F
300 deg F an hour to 1750 deg F then a 1 hr hold at 1750 deg F
50 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 0.08
Al2O3 0.57
SiO2 3.0
molecular percent Silica 63%
K2O 0.09
Al2O3 0.55
SiO2 3.0
molecular percent Silica 64%
three-inch-high cup, the glaze flows off the
bottom and glues itself to the kiln shelf.
waxy matte that is slightly translucent.
crystals differs greatly. Those of the second glaze,
iron_Alex_si, appear thicker, with more rounded edges.
the crystals of
iron_Alex_0 are more textured, with ragged edges, and a coppery metallic
sheen. Additionally
the crystals inside of the cup glazed with iron_Alex_si
have a green tinge.
iron than iron_Alex_si. At cone
10, iron is a strong flux - does that additional iron account for the
visible
differences in the appearance of these two glazes?
it isn't.
Image of the glaze iron_Alex_0
inside
outside
Image of the glaze iron_Alex_si
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 compositions
Empirical Formula iron_Alex_0 :
Na2O 0.37
Li2O 0.14
CaO 0.32
MgO 0.09
Fe2O3 0.15
P2O5 0.03
Empirical Formula iron_Alex_si :
Na2O 0.36
Li2O 0.14
CaO 0.32
MgO 0.09
Fe2O3 0.10
P2O5 0.03