disparate glazes at a vertical interface
Disparate glazes meeting at a vertical interface. The matrix (i.e. background)
glaze and inlay glaze overlap
The matrix glaze is a high iron, high alkali metal glaze. The inlay glaze, by
contrast,
Several closeups of the interaction region of the two glazes are shown and,
for context, a picture of the pot.
The background glaze is satIron_ZG_0, the foreground design is
glazed with alexanderBowl_0_Z1Y.
A thick glaze application resulted in large crystals forming in the
matrix glaze.
The design is created by adhering a mask and then applying the main
glaze. After drying, the mask is removed
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 1750 deg F then a half 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 0.1
Al2O3 0.59
SiO2 3.14
molecular percent Silica 63%
K2O .09
Al2O3 .43
SiO2 2.7
molecular percent Silica 65%
Added:
1% Cobalt Carbonate
.67% Copper Carbonate
As easter egg dye spreads by diffusion into the entire pot, the higher
concentration of CaO
Most of the increase in area covered by the inlay is attributable to crystal
growth in the matrix (background) glaze,
The mask for the inlay is a simple wiggly line. After firing, the inlay is
considerably broadened.
The closeup images were enhanced to increase the visibility of the crystals.
The yellow seen in
by no more than an eighth of an inch
before firing, with no overlap whatever for large parts of the design.
The original mask for the inlay was a curved line, a scribble,
and nowhere more than
half an inch across.
is high in alkaline earths, particularly CaO, and lower in alumina.
and the open area filled in with a
second glaze, using a bulb syringe.
Close up Images of the interaction region
Image of the piece
bowl with glaze satIron_ZG_0 and inlay alexanderBowl_0_Z1Y
bowl is ~9 inches in diameter
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
Background glaze
Empirical Formula satIron_ZG_0 :
Na2O 0.49
Li2O 0.19
CaO 0.16
MgO 0.06
Fe2O3 0.20
P2O5 0.04
Inlay Glaze
alexanderBowl_0_Z1Y :
Na2O .05
CaO .70
MgO .16
Remarks
Metallic micro-crystals appear in this glaze if applied thickly. Here we
see acicular crystals growing
in the interfacial region distinct from its
native metallic micro-crystals. These acicular crystals are reminiscent
of
those seen in the glaze
satIron_Ip7_5
in the inlay glaze will migrate into the matrix,
encouraging the creation of an additional crystalline phase
in the matrix
glaze.
and diffusion of the inlay glaze into
the matrix.
the inlay is the strong primary yellow as seen.