glazes interacting at vertical interface
The matrix (i.e. background) glaze and inlay glaze do not overlap before
firing.
The matrix glaze is a high alkali metal glaze containing titanium. The inlay
glaze contains
Here, we see the reverse pairing of inlay and matrix.
Several closeups of the interaction region of the two glazes are shown. For
context, a picture of the
The background glaze is hiAlk_Z3P_M_hAl, the inlay design is glazed with
zincSr_Z3S_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 0.13
Al2O3 0.63
SiO2 3.43
molecular percent Silica 64.31%
K2O 0.10
Al2O3 0.51
SiO2 2.75
molecular percent Silica 64.5%
Added:
2.5% Cobalt Carbonate
Both Zinc and titanium glazes will show micro-crystals, especially with long
holds. Here, with zinc in the
It is especially interesting that the matrix glaze completely overran the
inlay glaze, which was originally
strontium, zinc, and cobalt.
The background
glaze containing zinc, strontium and cobalt; the inlay glaze is high
in alkali metals
and contains titanium.
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
bowl with glaze hiAlk_Z3P_M_hAl and inlay glaze
zincSr_Z3S_0
bowl is ~6 inches in diameter
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 hiAlk_Z3P_M_hAl:
Na2O 0.49
CaO 0.36
MgO 0.02
P2O5 0.07
TiO2 0.21
Inlay Glaze:
Empirical Formula inlay zincSr_Z3S_0:
Na2O 0.30
CaO 0.02
MgO 0.24
SrO 0.15
ZnO 0.19
Remarks
inlay glaze and titanium in the matrix glaze,
there is diffusion of zinc into the matrix, and titanium into the inlay.
about 3/8" wide. Instead, the entire design
is comprised of the interaction region between the two glazes with
nothing
left of the character of the original inlay glaze.