Interacting Glazes
The matrix (i.e. background) glaze and inlay glaze do not overlap before
firing. The width of the
The inlay glaze is high in sodium, zinc, and titanium. The matrix glaze is
high in alkaline earths,
The inlay glaze contains nickel, cobalt and rutile.
In the inlay we see radiating bands of distinct colors and textures. At the
center, a mixed chartreuse/yellow
The nickel in the inlay glaze seems not to diffuse a great distance, with
cobalt diffusing the furthest, showing
While the matrix glaze contains some titanium, an unknown large quantity of
rutile was added to the inlay glaze.
The background glaze is woof-hank; the inlay design is glazed with
cooper_404_1Na_Z45.
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 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 hr hold at 1700 deg F
25 deg F an hour to 1650 deg F then a 1 hour hold at 1650 deg F
K2O 0.11
Al2O3 0.43
SiO2 2.9
molecular percent Silica 66.3%
K2O 0.07
Al2O3 0.40
SiO2 2.33
molecular percent Silica 62.3%
Added:
~2% Cobalt Carbonate
The matrix glaze, woof-hank, is a fluid high gloss glaze, which is crazed so
uninteresting in its own right,
original inlay varied from an eighth of an inch to
three eighths of an inch.
particularly calcium, and also containing both
barium and strontium. Quite a mix of diverse chemicals to
encourage a
range of chemical reactions.
with blue overtones. It is dominated
by sheaves of needle like crystals, likely zinc. Next is a band of
white
spherulitic bodies, then a band of blue, with seemingly blue
tinged sperulites. These blue spherulites
are seen through a blue
surface and are not themselves blue. The deep blue fades into the matrix
glaze
which can be seen to have a distribution of the spherulites for
some distance.
its characteristic color far past
the original inlay masks. I attribute the white spherulites to titanium,
which
don't take up either the nickel or cobalt.
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 woof-hank and inlay glaze cooper_404_1Na_Z45
bowl is ~7 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 woof-hank :
Na2O 0.04
CaO 0.60
MgO 0.09
BaO 0.07
SrO 0.09
P2O5 0.01
TiO2 0.05
Inlay Glaze:
Empirical Formula cooper_404_1Na_Z45:
Na2O 0.39
CaO 0.02
MgO 0.02
BaO 0.13
ZnO 0.37
TiO2 0.15
1.5% Nickel Oxide
~8% Rutile
Remarks
yet so very fluid that it allows rapid
diffusion of oxides. The result, it provides a medium for fascinating
effects.