Glazes reacting at a vertical interface
The matrix (i.e. background) glaze and inlay glaze do not overlap before
firing.
The matrix is a high alkali metal, saturated iron glaze. The inlay glaze is
lower in alkali metals,
The original inlay masks were continuous curves between three eights of
an inch and half an inch thick.
Several closeups of the interaction region of the two glazes are shown, and
additionally for context,
The background glaze is satIron_ZG_0, 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 0.10
Al2O3 0.59
SiO2 3.14
molecular percent Silica 63%
K2O 0.09
Al2O3 0.51
SiO2 2.9
molecular percent Silica 65.4%
Added:
Cobalt Carbonate 1%
In the close-up pictures one notes regions of inlay entirely absorbed
by the interaction region.
Iron has diffused from the matrix glaze into the inlay glaze, and calcium
in the opposite direction.
and contains no added iron. Both matrix and inlay
glaze contain some phosphorus.
The yellow color visible in the inlay is
entirely the result of diffusion of iron from the matrix glaze into
the
inlay glaze.
a picture of the pot is shown.
iron_Alex_1_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
pasta bowl with glaze satIron_ZG_0 and inlay glaze
iron_Alex_1_1MFe
bowl is ~10 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
Empirical Formula iron_Alex_1_1MFe
Na2O 0.27
Li2O 0.09
CaO 0.45
MgO 0.10
P2O5 0.02
Copper Carbonate 0.5%
Remarks