Reactions between glazes which abut and overlap
The interface of adjacent glazes from divergent glaze families.
The matrix glaze is a high iron glaze that is high in alkali metals;
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_satIron_Z2V_0; the foreground design is
glazed with alexanderBowl_0_Z1Y.
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 2315 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 0.19
Al2O3 0.55
SiO2 3.17
molecular percent Silica 63.8%
K2O 0.09
Al2O3 0.43
SiO2 2.67
molecular percent Silica 65%
Added:
1% Cobalt Carbonate
0.34% Chrome Oxide
The viscous inlay glaze is higher in alkaline earths, while the more
fluid background glaze is high
There are patches of a drippy black liquid that formed within the
matrix glaze, though only at the edge of the inlay glaze.
Small acicular crystals formed within the glossy black phase.
The close-up images have been heavily edited to show the structure of the
crystals forming in the interaction region,
is high in alkaline earths.
and the open area filled in with a
second glaze. As the step of waxing the pot before removal of the mask is
eliminated,
there is some overlap of the inlay glaze and matrix glaze. The
maximum width of the mask is ~ 3/4 inch, the maximum overlap
of the two
glazes, ~1/16 inch. The filling is done with an ear syringe which emits a
stream of approximately 1/8th
inch diameter.
Close up Images of the interaction region
Image of the piece
bowl with glaze iron_satIron_Z2V_0 and inlay alexanderBowl_0_Z1Y
bowl is 8 inches in diameter
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_satIron_Z2V_0 :
Na2O 0.3
Li2O 0.27
CaO 0.18
MgO 0.06
Fe2O3 0.20
P2O5 0.04
Inlay Glaze
Empirical Formula alexanderBowl_0_Z1Y :
Na2O 0.05
CaO 0.70
MgO 0.16
Fe2O3 0.02
Remarks
in alkali metals.
On a vertical wall,
it flowed mightily; like a river, it poured through everything and changed the
design greatly.
Like what happens to a watercolor painting on an easel if you
get it too wet.
with the result that the colors
are overly bright. The image of the bowl has accurate colors. The matrix
glaze is
covered in metallic micro-crystals and reflects like a mirror.