Glaze Reactions
The background glaze is a composite, with a surface of micro-crystalline
clusters atop a full gloss
The inlay glaze is a titanium matte with its own distinct micro-crystalline
clusters.
The matrix (i.e. background) glaze and inlay glaze overlap minimally before
firing. The width of the
The background glaze is zincSr_Z3TV_0_lAlk; the inlay design is glazed with
hiAlk_Z3P_MAl.
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 0.10
Al2O3 0.5
SiO2 2.75
molecular percent Silica 64.7%
added:
2.5% cobalt Carbonate
K2O 0.12
Al2O3 0.60
SiO2 3.28
molecular percent Silica 63.4%
The original inlay design was a continuous spiral. As the inlay glaze diffuses
into the background glaze,
The oxides of the background glaze and inlay glaze diffuse into each other,
and the micro-crystals of
The green edge seen between the inlay glaze and background glaze is the
interaction of cobalt and titanium.
The intricate pattern created by the interaction of these two glazes is the
result of the non-uniformity
cobalt blue substrate.
original inlay varied from an eighth of an inch to
three eighths of an inch.
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 zincSr_Z3TV_0_lAlk and inlay glaze hiAlk_Z3P_MAl
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 zincSr_Z3TV_0_lAlk :
Na2O 0.41
CaO 0.03
MgO 0.27
SrO 0.12
ZnO 0.07
Inlay Glaze:
Empirical Formula hiAlk_Z3P_MAl :
Na2O 0.51
CaO 0.35
MgO 0.02
P2O5 0.06
TiO2 0.22
Remarks
it moves most easily through the glassy
substrate, but it is impeded by the micro-crystalline cluster
within the
background glaze. The rhythmic indentations seen are where crystal
clusters have blocked
its movement.
background glaze block those of the inlay. Conversely
the crystals in the inlay glaze block movement of the
background glaze.
of the glazes. Both the background glaze and
inlay glaze are multi-phase assemblages. Each phase of
each glaze reacts
distinctly with the several phases of the other.