Quest for Calico
The first sighting of these unusual markings, which I'd described as calico,
were seen in a variation
This glaze, cooper_404_1Na shows a pattern of overlapping intersecting circles
of the colors dark blue green,
The surface of cooper_404_1Na is a dry matte, with the tactile appeal of
sandpaper.
The glaze cooper_404_1Na_Z47_0, my most recent effort in this quest, has a
smooth waxy matte surface.
bowl is ~ 4 inches in diameter.
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 0.08
Al2O3 0.34
SiO2 2.32
molecular percent Silica 63.4%
Added:
1.5% Nickel Oxide
K2O 0.08
Al2O3 .44
SiO2 2.4
molecular percent Silica 62.4%
Added:
1.5% Nickel Oxide
of glaze 404 of Emmanuel Cooper, from his book "The
Potter's Book of Glaze Recipes".
pale ivory, and orangey brown.
Image of the glaze cooper_404_1Na
bowl ~4 inches in diameter
The calico markings are much subdued.
Image of the glaze cooper_404_1Na_Z47_0
inside
outside
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
Empirical Formula cooper_404_1Na :
Na2O 0.28
CaO 0.05
MgO 0.01
BaO 0.21
ZnO 0.37
Empirical Formula cooper_404_1Na_Z47_0 :
Na2O 0.39
CaO 0.02
MgO 0.01
BaO 0.17
ZnO 0.32