iron colors in firings with slow up-fire
The glaze, wisskirchen-crystals-PAl is seen in firings with
and again with
Here in contrast there are no down-fire holds, rather this firing gets to
cone 10 at 2220 degF.
Firing:
In the down-fire, there are no holds. In the up-fire, the temperature
increases
The bowls is ~6 inches in diameter.
150 deg F an hour to 250 deg F
400 deg F an hour to 1850 deg F
120 deg F an hour to 2130 deg F
13 deg F an hour to 2190 deg F with a hold of 2 hours at 2190 deg F
13 deg F an hour to 2220 deg F with a hold of 3 hours at 2220 deg F
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K2O 0.10
Al2O3 0.55
SiO2 3.45
molecular percent Silica 64.6%
K2O 0.18
Al2O3 0.58
SiO2 3.61
molecular percent Silica 65.9%
There is a splash of the decoration glaze beneath the matrix glaze.
one down-fire hold.
several down-fire holds.
This is accomplished by an extreme slow ramp in the
up-fire.
at 13 deg F an hour, from 2130 deg F. There is a hold of 2
hours at 2190 deg F, and
another hold of 3 hour at 2220 deg F, the top
temperature reached in this firing.
Image of the glaze wisskirchen-crystals-PAl
oxidation firing to cone 10 in an electric kiln
Firing profile
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 wisskirchen-crystals-PAl:
Na2O 0.24
CaO 0.62
MgO 0.04
Fe2O3 0.31
TiO2 0.03
decoration Glaze:
Empirical Formula hiAlk_Z3P_Z3V_0Mng:
Na2O 0.35
CaO 0.45
MgO 0.02
P2O5 0.07
TiO2 0.21
Remarks