Interactions between Two Glazes

cone 10 oxidation

Firing profile

Up Fire profile

150 deg F an hour to 250 deg F

400 deg F an hour to 2050 deg F

120 deg F an hour to 2250 deg F

60 deg F an hour to 2310 deg F with a hold of 20 minutes at 2310 deg F

Down Fire Profile

A half hour hold at 1750 deg F

A three hour hold at 1700 deg F

slow downfire at 25 deg F an hour in the interval 1700 deg F to 1650 deg F

A one hour hold at 1650 deg F

The cones show this as a cone 10 firing.

On entering the kiln, the contrast inlay glaze abuted the background glaze. There was no overlap or gaps between the two.
Nevertheless In the closeups, one sees an interfacial region between the contrast glaze and the ground glaze,
which is distinct from both. Here we see two distinct background glazes with the same inlay glaze.

In the glaze alexanderBowl_Z15_0 there is a gradual migration of properties.
By contrast in the glaze hanksSatin_ZV_0 artifacts unrelated to either the background glaze or the inlay glaze appear.
One might do a line design in an inlay glaze, sufficiently thin that only the interfacial region appeared.
The purpose would be to capture the amazing interaction effects.

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

In each case I show an enlarged picture of the inlay, and also a picture of the entire bowl.

glaze composition of the background glazes

Emperical Formula alexanderBowl_Z15_0:

K2O        0.08
Na2O        0.05
Li2O        0.00
CaO        0.70
MgO        0.17

Al2O3        .48

SiO2        2.65

molecular percent Silica 64 %

Emperical Formula hanksSatin_ZV_0:

K2O        0.12
Na2O        0.04
Li2O        0.00
CaO        0.48
MgO        0.02
BaO        0.34

Al2O3        .38

SiO2        2.56

molecular percent Silica 65 %

Emperical Formula paperWhite_ZK_2 - inlay glaze:

K2O        0.21
Na2O        0.23
Li2O        0.05
CaO        0.20
MgO        0.01
SrO        0.30

Al2O3        .6

SiO2        3.02
TiO2        0.18

molecular percent Silica 63 %

glaze has .1 % Crome oxide added.

glaze alexanderBowl_Z15_0

bowl with paperWhite_ZK_0 inlay

close up of inlay

glaze hanksSatin_ZV_0

bowl with paperWhite_ZK_0 inlay

close up of inlay