Copper Red/Blue
My previous copper red work:
Here I show a number of glazes with copper red markings overlaid with mixtures
of blue and milky white. There are additional milk white glassy streaks
and
an opalescencent overlay.
The Kangxi family of glazes are viscous and uncrazed, contain no Li2O, and are
low in B2O3. They are high in silica with lower alkali metals
than many of my copper red glazes. In particular, the alkali metal:Alumina
ratio is less than or equal to 1.
The glaze tichane_Z1D_3 in showing blue, yet containing both B2O3 and Li2O.
It has high alkali metal alumina ratio, and lower silica.
While the blue
is a prominent feature of this glaze, it is not nearly so viscous as the
Kangxi glazes, is crazed, and the red beneath
the opalescence is splotchy.
The local reduction is produced by the inclusion of 1% of 1000 mesh silicon
carbide in the glaze recipe.
These glazes, as all my glazes, are mixed with CMC gum which aids in
maintaining the silicon carbide in suspension.
cone 10 oxidation
Firing profile
Up Fire profile
150 deg F an hour to 250 deg F
400 deg F an hour to 2050 deg F
120 deg F an hour to 2250 deg F
60 deg F an hour to 2310 deg F with a hold of 20 minutes at 2310 deg F
Down Fire Profile
A half hour hold at 1750 deg F
A three hour hold at 1700 deg F
slow downfire at 25 deg F an hour in the interval 1700 deg F to 1650 deg F
A one hour hold at 1650 deg F
The cones show this as a cone 10 firing.
K2O .13
Al2O3 .35
SiO2 3.8
molecular percent Silica 73%
I added 1% silicon Carbide and 1% Copper Carbonate to the above glazes
K2O .15
Al2O3 .39
SiO2 4.3
molecular percent Silica 74%
I added 1% silicon Carbide and 1% Copper Carbonate to the above glazes
K2O .08
Al2O3 .40
SiO2 3.6
molecular percent Silica 71%
I added 1% silicon Carbide and 1% Copper Carbonate to the above glaze
K2O .13
Al2O3 .4
SiO2 4.1
molecular percent Silica 74%
I added 1% silicon Carbide and 1% Copper Carbonate to the above glaze
K2O .22
Al2O3 .37
SiO2 4
molecular percent Silica 71%
I added 1% silicon Carbide and 1% Copper Carbonate to the above glaze
Clay body is a grolleg porcelain from Tacoma Clay Art Center.
glaze compositions
Empirical Formula glaze kangxi-cu-red-Z1D-0 :
Na2O .21
CaO .59
MgO .02
ZnO .05
SnO2 .02
Empirical Formula glaze kangxi-cu-red-Z1D-1 :
Na2O .25
CaO .53
MgO .02
ZnO .05
B2O3 .1
SnO2 .03
Empirical Formula glaze kangxi-cu-red-Z1E-1 :
Na2O .16
CaO .71
MgO .01
ZnO .04
SnO2 .05
Empirical Formula glaze kangxi-cu-red-Z1E-2 :
Na2O .21
CaO .6
MgO .01
ZnO .05
SnO2 .05
Empirical Formula glaze tichane_Z1D-3 :
Na2O .2
Li2O .1
CaO .42
MgO .01
ZnO .05
B2O3 .2
SnO2 .05
bowls are ~ 4 inches in diameter
glaze kangxi-cu-red-Z1D-0
glaze kangxi-cu-red_Z1D_1
glaze kangxi-cu-red_Z1E_1
glaze kangxi-cu-red_Z1E_2
glaze tichane-Z1D-3
