Intertwined abutting glazes
The interface of adjacent glazes.
Several closeups of the interaction region of the two glazes are shown and,
for context, a picture of the pot.
The background glaze is iron_8_R_C10_13PSi, 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 entire pot is coated in wax,
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 0.11
Al2O3 0.56
SiO2 3.12
molecular percent Silica 63%
K2O 0.09
Al2O3 0.43
SiO2 2.67
molecular percent Silica 65%
The background glaze and inlay glaze belong to different glaze families. The
background is a saturated iron glaze high in alkali metals;
Iron from the background matrix migrated into the inlay creating a range of
iron colors.
A border of crinkled glaze within the matrix surrounds the inlay. These
crystals have formed ( technically it is said neucleated)
The surface coverage of the inlay is not too different than it had been in
the original masks, though the inlay glaze has high viscosity
then the mask is removed
and the open area filled in with a second glaze.
Close up Images of the interaction region
Image of the piece
bowl with glaze iron_8_R_C10_13PSi and inlay alexanderBowl_0_Z1Y
bowl is ~9 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_8_R_C10_13PSi :
Na2O 0.45
Li2O 0.25
CaO 0.17
MgO 0.02
Fe2O3 0.28
Inlay Glaze
alexanderBowl_0_Z1Y :
Na2O 0.05
CaO 0.70
MgO 0.16
Remarks
the inlay glaze is low in alkali metals, high in CaO and has only trace
amounts of iron.
on the edge of the
inlay, as barnacles attach to a ships hull. The boundary of the inlay provides
the sticking place
for the beginning of crystal formation.
and the matrix
glaze flows readily.