Glaze Interactions
This is a further exploration of a firing which has a slow up-fire in
addition to having the usual holds
The matrix glaze is a high titanium glaze which develops titanium
micro-crystalline
As previously seen
here, the copper migrates into the background glaze,
In addition, the slow up-fire allows micro-crystals, once formed in the matrix
glaze, to migrate into
Large acicular crystals are seen overlapping the matrix glaze and inlay in the
first image. In the
In the third image there are a series of what appear to be small dark green
acicular crystals overlaying
The matrix (i.e., background) glaze and inlay glaze overlap minimally before
firing. The width of the
The design is created by adhering a mask and then applying the main
glaze. After drying,
The close-up images were heavily edited to enhance detail. The colors of the
full image of the bowl
400 deg F an hour to 1800 deg F
300 deg F an hour to 2050 deg F
200 deg F an hour to 2220 deg F then a 90 min hold at 2220 deg F
90 deg F an hour to 2320 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 hr hold at 1650 deg F
K2O 0.11
Al2O3 0.57
SiO2 3.11
molecular percent Silica 62.7%
K2O 0.10
Al2O3 0.38
SiO2 3.15
molecular percent Silica 68.4%
Added:
5.0% Copper Oxide
This firing features a 'rounded at the top' firing profile; with a hold of an
hour and a half at 100 degreesF
on the way down.
clusters in a glossy matrix if applied thin, or
is a micro-crystalline matte glaze if applied thickly.
The inlay glaze
is oribe-woof-black-M. This is a high-silica/low-alumina glaze, which
is a
full gloss glaze that develops small micro-crystal clusters.
staining the
titanium crystals brown or black depending on the degree of migration.
the inlay and, in some cases, continue to grow as
titanium continues to diffuse into the inlay region
during the slow approach
to top temperature. The micro-crystals which normally grow in the inlay glaze
will also act as sites for the growth of micro-crystals, explaining the
occurrence of such a
profusion of distinct crystals.
second image a rather large mass of micro-crystals has
migrated and continued growing in the inlay glaze.
the white crystals. These are translucent, and a
pale amber. The tint seen is the result of the image
manipulation that made
them visible.
original inlay varied from an eighth of
an inch to three quarters 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.
are as they appear in bright light.
Close up Images of the interaction region
Image of the piece
bowl with glaze hiAlk_Z3P_Z4E and inlay glaze oribe-woof-black-M
bowl is ~6 inches in diameter
oxidation firing to a hot cone 10 in an electric kiln
Firing profiles
Up Fire profile hot cone 10
Down Fire Profile hot cone 10
Clay body is a grolleg porcelain from Clay Art Center in Tacoma, WA.
glaze composition
Empirical Formula hiAlk_Z3P_Z4E :
Na2O 0.50
CaO 0.37
MgO 0.02
P2O5 0.06
TiO2 0.22
Inlay Glaze:
Empirical Formula oribe-woof-black-M
Na2O 0.04
CaO 0.69
MgO 0.17
P2O5 0.01
ZrO2 0.05
0.75% Cobalt Carbonate
Remarks
below top temperature, and a slow climb
from there to the top temperature.