The interaction at the interface of adjacent glazes.
Several closeups of the interaction region of the two glazes are shown and,
for context, a picture of the pot.
The background glaze is satIron_ZG_1S_1Munge, the foreground design is
glazed with iron_8_R_C10_13PSi.
The design is created by adhering a mask and then applying the main
glaze. After drying, the entire pot is coated in wax,
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 2300 deg F
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
K2O .06
Al2O3   .53
SiO2   3.28
molecular percent Silica 63%
K2O .11
Al2O3   .56
SiO2   3.12
molecular percent Silica 63%
The interaction region dominates the design, occasionally leaving nothing
untouched of the design glaze inlay.
The design glaze, iron_8_R_C10_13PSi, differs from the background glaze
satIron_ZG_1S_1Munge in that
Otherwise, these two glazes seem to be saturated iron glazes with similar
compositions.
then the mask is removed
and the open area filled in with a second glaze.
Close up Images of the interaction region
Image of the piece
bowl with glaze satIron_ZG_1S_1Munge and inlay iron_8_R_C10_13PSi
bowl is ~7 inches in diameter
oxidation firing to cone 10 in an electric kiln
Firing profiles
Up Fire profile
Down Fire Profile
Clay body is a grolleg porcelain from Tacoma Clay Art Center.
glaze compositions
Background glaze
Empirical Formula satIron_ZG_1S_1Munge :
Na2O .51
Li2O .21
CaO .21
MgO .01
Fe2O3   .19
P2O5   0.16
Inlay Glaze
iron_8_R_C10_13PSi :
Na2O .45
Li2O .25
CaO .17
MgO .02
Fe2O3   .28
Remarks
it contains no P2O5.
Phosphorus has a strong effect on the character of a glaze.