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 is a saturated iron glaze with an aventurine sparkle, as is
seen in the
This same inlay glaze is seen
here, as inlay in a microcrystalline matte glaze.
Several closeups of the interaction region of the two glazes are shown and,
for context,
The background glaze is iron_8_R_C10_13PSi, the inlay design is
glazed with
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
200 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 50 minute 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 0.11
Al2O3 0.56
SiO2 3.12
molecular percent Silica 63%
K2O 0.07
Al2O3 0.53
SiO2 2.97
molecular percent Silica 64.6%
The original inlay, as placed in the kiln, was a simple curve, about 3/8th of
an inch thick.
The matrix glaze and inlay glaze have nearly the same silica:alumina ratio,
with the result that the
image of the mug. The inlay glaze is a microcrystalline
matte.
note the difference
in appearance of the interaction region.
a picture of the pot.
iron_Alex_1MFe.
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
mug with glaze iron_8_R_C10_13PSi and inlay glaze
iron_Alex_1MFe.
mug is ~4.5 inches high
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_8_R_C10_13PSi :
Na2O 0.45
Li2O 0.25
CaO 0.17
MgO 0.02
Fe2O3 0.28
Inlay Glaze
Empirical Formula iron_Alex_1MFe:
Na2O 0.34
Li2O 0.11
CaO 0.37
MgO 0.11
Fe2O3 0.08
P2O5 0.02
Remarks
Here the two glazes combine to form a new full gloss
glaze with acicular crystals. The micro-crystals
which characterize the inlay
glaze are nowhere to be seen.
primary difference between the two glazes is in
the higher iron and higher alkali metals of the matrix glaze.
The iron in the
matrix glaze is behaving as a flux. This together with the higher alkali
metals of the matrix
glaze account for the full gloss glaze created in
the interaction region. The swirled smoky
streaks in the interaction
region are an indication of the intensity of this interaction.