Interacting glazes at a vertical interface
Glazes interacting at a vertical interface.
The matrix (i.e. background) glaze and inlay glaze do not overlap before
firing.
The matrix glaze appears as if it had many translucent layers. It is a
saturated iron glaze, and is applied in
A closeup of the matrix glaze, and several closeups of the interaction region
of the two glazes are shown and,
The background glaze is iron_Alex_0PPSi_MMg, the inlay design is
glazed with iron_Alex_1MFe_0.
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 1800 deg F then a two hour hold at 1800 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 0.09
Al2O3 0.58
SiO2 4.1
molecular percent Silica 69.3%
K2O 0.07
Al2O3 0.53
SiO2 3.0
molecular percent Silica 65.3%
Note the glassy black frame surrounding the inlay, a color and texture which
occurs nowhere in either
Note the gaps in the line drawing on the bowl, there were no gaps in the masks
for the inlay.
The matrix glaze is higher in silica, and also in alkali metals, than the inlay
glaze. The differing composition
the usual manner. The inlay glaze
is a microcrystalline matte. It is seen
here with higher iron.
for context, a picture of the pot.
the mask is removed and the open area filled in with a
second glaze, using a bulb syringe
with a needle applicator.
Close up Image of the matrix glaze
Close up Images of the interaction region
Image of the piece
bowl with glaze iron_Alex_0PPSi_MMg and inlay glaze
iron_Alex_1MFe_0.
inside of bowl
bowl is ~6 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 iron_Alex_0PPSi_MMg:
Na2O 0.45
Li2O 0.17
CaO 0.27
MgO 0.02
Fe2O3 0.16
P2O5 0.07
Inlay Glaze
Empirical Formula iron_Alex_1MFe_0:
Na2O 0.34
Li2O 0.11
CaO 0.37
MgO 0.11
Fe2O3 0.04
P2O5 0.02
Remarks
the matrix glaze iron_Alex_0PPSi_MMg, nor in the pale
yellow microcrystalline inlay glaze iron_Alex_1MFe_0.
The gaps are entirely the result of the matrix glaze eating
the inlay.
allows the formation of phases present in
neither of these glazes.