unrelated glazes at a vertical interface
Dissimilar glazes interacting at a vertical interface.
The matrix (i.e. background) glaze and inlay glaze do not overlap before
firing.
The matrix glaze is high in alkaline earths, Calcium and Magnesium. The inlay
glaze, by contrast,
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_Alex_1_1PSi, the inlay design is
glazed with satIron_ZG_1S_1Munge_3MMG_0.
The design is created by adhering a mask and then applying the main
glaze. After drying, the mask is removed
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
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 0.09
Al2O3 0.51
SiO2 3.28
molecular percent Silica 66.3%
K2O 0.20
Al2O3 0.51
SiO2 2.97
molecular percent Silica 61.5%
The higher concentrations of alkali metals and Phosphorus migrate from the
inlay glaze into the matrix, seeding
In the interaction region, we see visible yellow acyclic crystals on a dark
glossy background. These crystals
The glossy black phase seen in the interaction region is not otherwise seen
in either of these glazes.
Most of the increase in area covered by the inlay is attributable to
dissolution of the matrix glaze
The original mask for the inlay was a curved line, nowhere
more than three eights of an inch thick.
is higher in alkali metals and Iron, and contains
substantial Phosphorus.
and the open area filled in with a
second glaze, using a bulb syringe with a needle applicator.
Close up Images of the interaction region
--
Image of the piece
mug with glaze iron_Alex_1_1PSi and inlay satIron_ZG_1S_1Munge_3MMg_0
mug is ~4.5 inches in 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_Alex_1_1PSi :
Na2O 0.26
Li2O 0.09
CaO 0.42
MgO 0.14
Fe2O3 0.13
P2O5 0.02
Inlay Glaze
Empirical Formula satIron_ZG_1S_1Munge_3MMg_0:
Na2O 0.43
Li2O 0.20
CaO 0.16
MgO 0.01
Fe2O3 0.19
P2O5 0.17
Remarks
additional phases in the matrix
glaze.
are also present in the matrix glaze
iron_Alex_1_1PSi, yet are small, so unnoticed.
resulting from diffusion of inlay glaze into
the matrix.