Interacting glazes at a vertical interface
The matrix (i.e. background) glaze and inlay glaze do not overlap before
firing.
The matrix glaze is a high alkali glaze containing zinc and strongtium.
The inlay glaze
As a consequence of the extra volume of matrix glaze, created by a thick glaze
application, there is
Several closeups of the interaction region of the two glazes are shown, and
additionally a closeup
The background glaze is zincSr_Z3T_PZn_PSi_3, the inlay design is glazed with
hiAlk_Z3P_Z3V_0.
The design is created by adhering a mask and then applying the main
glaze. After drying,
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 1650 deg F then a 3 hr hold at 1650 deg F
400 deg F an hour to 1850 deg F then a 2 hr hold at 1850 deg F
300 deg F an hour to 1750 deg F then a 1 hr hold at 1750 deg F
300 deg F an hour to 1700 deg F then a 3 hour hold at 1700 deg F
K2O 0.15
Al2O3 0.52
SiO2 3.23
molecular percent Silica 67.7%
Added:
2.5% Cobalt Carbonate
K2O 0.18
Al2O3 0.64
SiO2 3.54
molecular percent Silica 64.9%
Both Zinc and titanium glazes will show micro-crystals, especially with long
holds. Here, with Zinc in the
is a mixed gloss with microcrystals containing
titanium.
sufficient matrix glaze to absorb much of the
applied inlay glaze. The interaction region is nearly the
same area as the
remaining remnant of pure inlay glaze. The original width of the inlay
was about
3/8th of an inch.
of the matrix glaze. For context, a picture of the
pot is shown.
the mask is removed 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 zincSr_Z3T_PZn_PSi_3 and inlay glaze
hiAlk_Z3P_Z3V_0
mug is ~4 inches high
oxidation firing to cone 10 in an electric kiln
Firing profiles
Up Fire profile cone 10
Down Fire Profile cone 10
Clay body is a grolleg porcelain from Clay Art Center in Tacoma, WA.
glaze composition
Empirical Formula zincSr_Z3T_PZn_PSi_3:
Na2O 0.32
CaO 0.02
MgO 0.18
SrO 0.14
ZnO 0.19
Inlay Glaze:
Empirical Formula inlay hiAlk_Z3P_Z3V_0:
Na2O 0.41
CaO 0.31
MgO 0.10
P2O5 0.07
TiO2 0.21
Remarks
matrix glaze and titanium in the inlay glaze,
there is diffusion of zinc into the inlay, and titanium into
the matrix,
enriching the interaction region.