Reactions at the interface between two glazes
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 iron_Z26_half, the foreground design is
glazed with mashiko_ZJ_2.
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 .07
Al2O3 .6
SiO2 3.4
molecular percent Silica 63.5%
K2O .09
Al2O3 .82
SiO2 5.73
molecular percent Silica 74%
The interaction region dominates the design, leaving only scattered bits
of the design glaze inlay.
The design glaze, mashiko_ZJ_2, differs from the background glaze
iron_Z26_half in that it contains no P2O5,
These are both saturated iron glazes, yet dissimilar in character, the result
is an interaction region which is unlike either glaze,
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
mug with glaze iron_Z26_half and inlay mashiko_ZJ_2
mug is ~5 inches high
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 iron_Z26_half :
Na2O .6
Li2O .22
CaO .1
MgO .01
Fe2O3 .24
P2O5 .14
Inlay Glaze
mashiko_ZJ_2 :
Na2O .1
Li2O .09
CaO .31
MgO .41
Fe2O3 .23
Remarks
is higher in silica, and lower
in alkali metals.
both in range of colors
and texture.