Migrating 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 mashiko_satIron_Z2Q; the foreground design is
glazed with iron_8_R_C10_13PSi.
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 0.10
Al2O3 0.81
SiO2 4.22
molecular percent Silica 68%
K2O 0.11
Al2O3 0.56
SiO2 3.12
molecular percent Silica 63%
A pair of contrasting glazes gives the most interesting effects. Here, the
matrix glaze is higher in MgO,
The inlay glaze is fluid, the matrix glaze viscous.
The inlay slides down the near vertical wall of the mug, yet maintains its
dimensions and general form,
The alkali metals diffuse from inlay to matrix simultaneously with the
downward movement of the inlay.
The pale microcrystals seen on the design are present in the background
matrix. Similar in hue and
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
mug with glaze glaze mashiko_satIron_Z2Q and inlay iron_8_R_C10_13PSi
mug is 4.5 inches in height
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 mashiko_satIron_Z2Q :
Na2O 0.30
Li2O 0.16
CaO 0.20
MgO 0.24
Fe2O3 0.17
P2O5 0.04
Inlay Glaze
Empirical Formula iron_8_R_C10_13PSi :
Na2O 0.45
Li2O 0.25
CaO 0.17
MgO 0.02
Fe2O3 0.28
Remarks
alumina and silica; the inlay glaze higher
in alkali metals and iron.
though leaving behind bits of itself. The
dark bluish shadow and brown fringe show the position of the
original design
mask.
Competing unrelated processes on
different clocks causes the raggedy matrix-inlay boundary seen.
color saturation to the matrix, together with
a multitude of alternate inclusions, they escape attention.