Glaze Reactions
The background (matrix) glaze is cooper_404_Z4E_1; the inlay design is
glazed with
The matrix glaze is derived from Emmanuel Cooper's glaze 404 from his book "The
Potters Book of Glaze Recipes."
In a prior examples the same inlay glaze
is seen surrounded by the matrix glaze
cooper_404_1Na_PMZn,
Both of these matrix glazes belong to the same glaze family and exhibit calico
markings. This glaze,
Though the interaction regions are similar, there are differences. The most
striking are the individual
This background glaze, having higher silica, is not as completely dissolved by
the inlay glaze.
The matrix (i.e., background) glaze and inlay glaze overlap minimally before
firing. The width of the
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 0.06
Al2O3 0.33
SiO2 2.83
molecular percent Silica 68%
Added:
1.5% Nickel Oxide
K2O 0.10
Al2O3 0.35
SiO2 3.29
molecular percent Silica 70.58%
Added:
5.0% Copper Oxide
oribe-woof-PAl-PSiMg.
also derived from Cooper's glaze 404.
cooper_404_4E_1 has lower alkali metals, and higher
silica than the prior glaze cooper_404_1Na_PMZn.
crystal clusters seen in the interaction
region in the second close up image. I expect these are
zinc crystals.
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
Close up Image of the background glaze
Image of the piece
bowl with glaze cooper_404_Z4E_1 and inlay oribe-woof-PAl-PSiMg
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 cooper_404_Z4E_1 :
Na2O 0.14
CaO 0.03
MgO 0.01
BaO 0.34
ZnO 0.42
Inlay Glaze:
Empirical Formula oribe-woof-PAl-PSiMg:
Na2O 0.04
CaO 0.61
MgO 0.25
P2O5 0.01