Glaze Reactions
The background glaze is glossy, aqua tinted, blue-black with a prominent dusting
of sharply delimited
The inlay glaze has eaten its way into the matrix glaze, many times the width
of the original masks.
The variation in rates of diffusion of the titanium and alkali metals from the
inlay into the matrix,
A variant of this glaze, with the same inlay glaze, has been seen previously
here.
The glaze seen here, oribe-woof-black-M is lower in alumina and higher in
silica than the prior glaze.
Both glazes are low in alkali metals and high in alkaline earths. A small
shift in the Silica:Alumina
The matrix (i.e. background) glaze and inlay glaze do not overlap before
firing. The width of the
The background glaze is oribe-woof-black-M; the inlay design is glazed with
hiAlk_Z3P_MAl.
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 0.10
Al2O3 0.38
SiO2 3.15
molecular percent Silica 68.4%
added:
5% black copper oxide
0.75% cobalt carbonate
K2O 0.12
Al2O3 0.60
SiO2 3.28
molecular percent Silica 63.4%
white micro-crystalline inclusions.
From the center out to the edge there are
successive bands of metallic silvery grey in two shades,
then brown, orange
and a mixture of aqua and blue.
and cross diffusion of silica into the inlay creates
the banded pattern seen.
ratio has created a large shift in the texture of
the glaze, this glaze is a full gloss, the other a waxy matte.
original inlay varied from an eighth of an inch to
three eighths of an inch.
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 oribe-woof-black-M and inlay glaze hiAlk_Z3P_MAl
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 oribe-woof-black-M :
Na2O 0.04
CaO 0.69
MgO 0.17
P2O5 0.01
ZrO2 0.05
Inlay Glaze:
Empirical Formula hiAlk_Z3P_MAl :
Na2O 0.51
CaO 0.35
MgO 0.02
P2O5 0.06
TiO2 0.22