Reactions between glazes which abut and overlap
The interface of adjacent glazes from divergent glaze families.
The matrix glaze is a high iron glaze that is high in alkali metals and
alumina; 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_Ip7_5; the foreground design is
glazed with alexanderBowl_0_Z1Y.
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 0.07
Al2O3 0.71
SiO2 3.13
molecular percent Silica 63%
K2O 0.09
Al2O3 0.43
SiO2 2.67
molecular percent Silica 65%
Added:
1% Cobalt Carbonate
0.34% Chrome Oxide
The viscous inlay glaze is higher in alkaline earths, while the more
fluid background glaze is high
The mask for the inlay is a pair of ovoids, each of width varying from a
quarter inch to three quarters of an inch.
is high in alkaline earths and lower in
alumina.
and the open area filled in with a
second glaze. As the step of waxing the pot before removal of the mask is
eliminated,
there is some overlap of the inlay glaze and matrix glaze. The
maximum width of the mask is ~ 3/4 inch, the maximum overlap
of the two
glazes, ~1/8 inch. The filling is done with an ear syringe which emits a
stream of approximately 1/8th
inch diameter.
Close up Images of the interaction region
Image of the piece
mug with glaze satIron_ZG_Ip7_5 and inlay alexanderBowl_0_Z1Y
mug is 4 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 satIron_ZG_Ip7_5 :
Na2O 0.43
Li2O 0.20
CaO 0.13
MgO 0.17
Fe2O3 0.1
P2O5 0.04
Inlay Glaze
Empirical Formula alexanderBowl_0_Z1Y :
Na2O 0.05
CaO 0.70
MgO 0.16
Fe2O3 0.02
Remarks
in alkali metals, silica and alumina.
The inlay flowed considerably
beyond its slight overlay of the matrix, nearly tripling its original
width.