Interacting glazes at a vertical interface
Glazes interacting at a vertical interface.
The matrix (i.e. background) glaze and inlay glaze do not overlap before
firing.
The matrix glaze is a saturated iron glaze with several distinct crystals.
Several closeups of the interaction region of the two glazes are shown, and
additionally for context,
The background glaze is satIron_ZG_Ip7_5_Calcined_Puah_18, the inlay design is
glazed with
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
200 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 1750 deg F then a 50 minute 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 0.10
Al2O3 0.72
SiO2 3.1
molecular percent Silica 62.3%
K2O 0.13
Al2O3 0.43
SiO2 2.7
molecular percent Silica 63.4%
Added:
Cobalt Carbonate 1%
Both the inlay glaze and matrix glaze grow visible crystals, though of
distinct composition and morphology.
The band closest to the inlay, dominated by the inlay, shows a disorganized
arrangement of needle crystals in iron
Next is a band of coppery colored acicular crystals, similar to those seen
in the matrix glaze.
Surrounding this band of crystals are crystals that belong to the matrix, yet
have nucleated at the
The matrix glaze, in addition to the large coppery colored acicular
crystals, features a dusting of bubble
From this occurrence of these crystals, above, it is clear that the acicular
crystals are not on the surface
a picture of the pot is shown.
hankPaper_Z1R_2C_1Var.
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
plate with glaze satIron_ZG_Ip7_5_Calcined_Puah_18 and inlay glaze
hankPaper_Z1R_2C_1Var
plate is 10 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 satIron_Ip7_5_Calcined_Puah_18 :
Na2O 0.44
Li2O 0.19
CaO 0.17
MgO 0.10
Fe2O3 0.09
P2O5 0.04
Inlay Glaze
Empirical Formula hankPaper_Z1R_2C_1Var:
Na2O 0.12
Li2O 0.05
CaO 0.14
MgO 0.01
BaO 0.31
SrO 0.24
TiO2 0.14
Copper Carbonate 0.5%
Remarks
The result of these contrasting
crystals is that the interfacial region has distinct bands radiating out
from the inlay.
colors, primarily dark brown.
These needle crystals most nearly resemble the blue crystals seen in the
central parts of the inlay.
edge of this interfacial region; as rock candy
grows on a string suspended in a saturated sugar solution.
shaped metallic crystals. The
surprise here, showm in the close-up pictures, is that these metallic bubble
crystals are seen atop the acicular crystals.
of the glaze but submerged
within the glaze.