Glaze Reactions
The matrix glaze satIron_ZG_Z3N_Z4A_0, is a saturated iron glaze with large,
diffuse leopard spots.
The inlay sits atop a diffuse band of mixed silvery gunmetal and orange
matrix glaze.
The interaction region frames an abstract turquoise spiral, having bands
of deep brooding glossy
A similar leopard spot glaze with related inlay glazes
is seen here:
Small differences in both inlay glaze and matrix glaze result in a dominant
design and a frame
The matrix (i.e., background) glaze and inlay glaze overlap minimally before
firing. The width of the
The background glaze is satIron_ZG_Z3N_Z4A_0; the inlay design is glazed with
oribe-woof-PAl-PSiMg, and
The design is created by adhering a mask and then applying the main
glaze. After drying,
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 hr hold at 1850 deg F
300 deg F an hour to 1750 deg F then a 1 hr hold at 1750 deg F
300 deg F an hour to 1700 deg F then a 3 hr hold at 1700 deg F
25 deg F an hour to 1650 deg F then a 1 hour hold at 1650 deg F
K2O 0.14
Al2O3 0.69
SiO2 3.65
molecular percent Silica 64.6%
K2O 0.10
Al2O3 0.35
SiO2 3.29
molecular percent Silica 70.58%
Added:
5.0% Copper Oxide
K2O 0.16
Al2O3 0.29
SiO2 2.70
molecular percent Silica 67.47%
Added:
5.0% Copper Oxide
The matrix glaze seen here, satIron_ZG_Z3N_Z4A_0 has slightly lower alumina,
and slightly higher
There are two inlay glazes, one of which also has lower alumina and is also as
a result more fluid.
A more fluid inlay in a more fluid matrix, allows the inner part of the inlay
to expand. More,
Nearly inconsequential differences in both the inlay and matrix glazes
shift the final
The leopard spots are matte black iron micro-crystals, they are a second phase
which formed in the glaze.
The leopard spots form by an interesting mechanism - bubbles form in the
glaze. Those bubbles have
black and iron-yellow streaks of foam. It
stands atop a diffuse gunmetal band, which fades
into the matrix glaze.
that recedes into the background rather than
upstaging the design.
original inlay varied from an eighth of an inch to
three eighths of an inch.
oribe-woof-PAlk.
the mask is removed and the open area filled in with a
second glaze, using a bulb syringe
with a needle applicator.
Close up Images of the interaction region
Image of the piece
bowl with glaze satIron_ZG_Z3N_Z4A_0
bowl is ~6 inches in diameter
oxidation firing to cone 10 in an electric kiln
Firing profiles
Up Fire profile cone 10
Down Fire Profile cone 10
Clay body is a grolleg porcelain from Clay Art Center in Tacoma, WA.
glaze composition
Empirical Formula satIron_ZG_Z3N_Z4A_0 :
Na2O 0.56
CaO 0.28
MgO 0.02
Fe2O3 0.23
P2O5 0.07
Inlay Glazes:
Empirical Formula oribe-woof-PAl-PSiMg:
Na2O 0.04
CaO 0.61
MgO 0.25
P2O5 0.01
Empirical Formula oribe-woof-PAlk:
Na2O 0.05
CaO 0.64
MgO 0.15
P2O5 0.01
Remarks
alkali metal:alumina ratio than that of the prior note
satIron_Zg_Z3N_EPK, and as a result is more fluid.
This is seen in the form
taken by its leopard spots. Here the bubbles which burst to form the
leopard
spots are larger, as they were able to expand to a greater size in a
more fluid glaze. These larger bubbles
burst leaving only their perimeter.
the interaction with the matrix glaze isn't dominated by the
copper, other oxides interacted as well,
so that the brooding dark band of
copper in the matrix glaze isn't as dominant as in the prior example.
appearance considerably.
Formed by a different mechanism than the coppery
colored micro-crystals seen on the rim, but same phenomenon,
a different
phase. Each phase has its own colors, the leopard spots matte black. The
iron distributes
itself differently in each phase.
a surface, just as the surface of the glaze, an
interface between glaze and gas. the black micro-crystals
grow on the bubble
surface, when the bubble reaches the glaze surface and bursts, those
micro-crystals
remain as relics of the bubbles.