The Edge between two glazes

A glaze from the interaction region seen here .

The glaze shown in this note, iron_Alex_0, is a mixture of the two glazes satIron_ZG_0 and alexanderBowl_0_Z1Y.

The interaction region between the two glazes, satIron_ZG_0 and alexanderBowl_0_Z1Y fascinates me.
This time, I didn't bother with the line blend, rather as they say, threw a dart into a black hole.

Past experience found the interesting artifacts in the interactions between a high alkali metal glaze, and a high CaO
semi-matte glaze, nearer the high alkali metal end of things. So that's what I did.

This glaze is three quarters satIron_ZG_0, one quarter alexanderBowl_0_Z1Y. I think of it as "spicing"
the glaze satIron_ZG_0, with a bit of alexanderBowl_0_Z1Y.



Image of the glaze iron_Alex_0

full view

inside



full view

outside

bowl is ~ 3.5 inches in diameter.



oxidation firing to cone 10 in an electric kiln

Firing profiles

Up Fire profile

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

Down Fire Profile

300 deg F an hour to 1750 deg F then a half hour hold at 1750 deg F

300 deg F an hour to 1700 deg F then a Three hour hold at 1700 deg F

25 deg F an hour to 1650 deg F then a one hour hold at 1650 deg F

Clay body is a grolleg porcelain from Tacoma Clay Art Center.



glaze compositions

Empirical Formula iron_Alex_0 :

K2O        0.08
Na2O        0.37
Li2O        0.14
CaO        0.32
MgO        0.09

Al2O3        0.57
Fe2O3        0.15

SiO2        3.0
P2O5        0.03

molecular percent Silica 63%



Empirical Formula satIron_ZG_0 :

K2O        0.1
Na2O        0.49
Li2O        0.19
CaO        0.16
MgO        0.06

Al2O3        0.59
Fe2O3        0.20

SiO2        3.14
P2O5        0.04

molecular percent Silica 63%



Empirical Formula alexanderBowl_0_Z1Y :

K2O        .09
Na2O        .05
CaO        .70
MgO        .16

Al2O3        .43
Fe2O3        0.02

SiO2        2.7

molecular percent Silica 65%



Remarks

The glaze shown here was derived similarly to a previously seen glaze satIron_P_Alex.

The acicular crystals seen in this glaze are similar to those seen in satIron_P_Alex, though the
resemblance between these two glazes ends there. The glaze iron_Alex_0 sports, in addition to the largish acicular crystals,
a scattering of metallic yellow micro-crystals and various other crystalline precipitates.

The acicular micro-crystals are large only if the glaze is thickly applied, whence it runs badly,
and the background glaze is entirely eaten by the crystals. This glaze is a work in progress.

The crystals are nearly ~1/4 inch in diameter. These micro-crystals while small, are visible.

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