Glaze Reactions
The matrix is a pale translucent aqua with diffuse dark markings.
The inlay is opaque and glossy with white micro-crystalline clusters, perhaps
a sixteenth of an inch
The interaction between the inlay and matrix is a two-layer frame of the
inlay. The inner layer
The matrix (i.e. background) glaze and inlay glaze do not overlap before
firing. The width of the
The background glaze is sr_Z40_PSr; the inlay design is glazed with
oribe-woof-MAlk-PPSi.
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
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 1850 deg F then a 2 hr hold at 1850 deg F
300 deg F an hour to 1750 deg F then a 1 hr hold at 1750 deg F
300 deg F an hour to 1700 deg F then a 3 hr hold at 1700 deg F
25 deg F an hour to 1650 deg F then a 1 hour hold at 1650 deg F
K2O 0.11
Al2O3 0.52
SiO2 3.08
molecular percent Silica 66.9%
added:
3% copper oxide
K2O 0.08
Al2O3 0.29
SiO2 3.45
molecular percent Silica 72.5
Added:
2% Cobalt Carbonate
in diameter, in a dark grey-blue ground.
is a nearly black inner fragmented band, as
glossy as the inlay glaze, surrounded by a nearly
white outer frame
carved out of the matrix glaze. One is irresistibly led to think that
something
migrated out of the matrix into the inlay to create the dark
band leaving behind a depleted region in
the matrix.
original inlay varied from an eighth of an inch to
three eighths of an inch.
It had cobalt and Zircopax added to the copper
already present. The additional oxides were
not measured.
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
bowl with glaze sr_Z40_PSr with inlay oribe-woof-MAlk-PPSi
bowl is ~7 inches in diameter
oxidation firing to cone 10 in an electric kiln
Firing profiles
Up Fire profile cone 10
Down Fire Profile cone 10
Clay body is a grolleg porcelain from Clay Art Center in Tacoma, WA.
glaze composition
Empirical Formula sr_Z40_PSr :
Na2O 0.22
CaO 0.20
MgO 0.01
SrO 0.46
Inlay Glaze:
Empirical Formula oribe-woof-MAlk-PPSi:
Na2O 0.03
CaO 0.72
MgO 0.17
P2O5 0.01
5.0% Copper Oxide
5% Zircopax