Glaze Interactions
This is a further exploration of a firing which has a slow up-fire in
addition to having the usual
The matrix glaze is a high silica/low alumina gloss glaze containing zircon,
densely
Nearly the same combination of matrix glaze and inlay glaze has been seen
here, without the
The slow up-fire allows micro-crystals to form in both matrix and inlay.
These crystals migrate
That there are many distinct crystals formed within the interaction region is
observed in the quantity
In the third close-up, silvery metallic globules resembling molten metal are
visible.
The formation of the nuclei, the sites for crystal, requires that the materials
in the glaze slops
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
120 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 0.10
Al2O3 0.41
SiO2 2.97
molecular percent Silica 65.97%
Added:
5.0% Copper Oxide
K2O 0.13
Al2O3 0.63
SiO2 3.36
molecular percent Silica 63.6%
This firing features a 'rounded at the top' firing profile; with a hold of an
hour and a half at 100 degreesF
holds on the way down.
covered in micro-crystals. The inlay glaze is a titanium bearing
saturated iron glaze, which
contributes its own distinct crystals.
retarded up-fire, with greatly different results.
across the boundary between the two glazes and
also act as sites for the growth of foreign crystals,
providing a rich
environment in which a multitude of distinct crystals can form.
of distinct crystal morphologies seen. There are
acicular crystals with radial spokes resembling the
underside of a mushroom.
One sees continuity of color through crystals, indicating translucency.
decompose, releasing their oxides to the melt. A slow
approach to top temperature provides time
for this process.
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 oribe-woof-PAlZr and inlay satIron_ZG_Z3N_Z4A+hiAlk_Z3P_Z4E
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 oribe-woof-PAlZr :
Na2O 0.03
CaO 0.71
MgO 0.16
P2O5 0.01
ZrO2 0.11
Inlay Glaze:
Empirical Formula satIron_ZG_Z3N_Z4A+hiAlk_Z3P_Z4E:
Na2O 0.52
CaO 0.33
MgO 0.02
Fe2O3 0.11
P2O5 0.07
TiO2 0.12
Remarks
below top temperature, and a slow climb
from there to the top temperature.