Rutile with copper
Here are two near neighbor glazes, hiAlk_Z3P_Oribe and hiAlk_Z3P_Oribe_12_1,
containing both copper and
The second glaze has higher alumina, lower silica, and higher titanium. Only a
remnant of the glossy matrix
The image of the inside of the second glaze was edited to decrease glare.
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 0.11
Al2O3 0.54
SiO2 3.31
molecular percent Silica 65.01%
added:
3% copper carbonate
K2O 0.11
Al2O3 0.59
SiO2 3.34
molecular percent Silica 64%
added:
3% copper oxide
The second glaze has slightly higher copper as a result of the inclusion of
copper oxide rather than
rutile. A small shift in composition results in
a large change in appearance.
surrounding the micro-crystalline titanium
clusters seen in the first glaze remains in the second glaze.
In the
second glaze bright orange inclusions, nowhere visible in the first glaze,
are seen in some of the
titanium crystal clusters.
Image of the glaze hiAlk_Z3P_Oribe
inside
outside
bowl is ~3.5 inches in diameter
Image of the glaze hiAlk_Z3P_Oribe_12_1
inside
outside
bowl is ~3.5 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 compositions
Empirical Formula hiAlk_Z3P_Oribe :
Na2O 0.45
CaO 0.40
MgO 0.04
P2O5 0.52
TiO2 0.18
Empirical Formula hiAlk_Z3P_Oribe_12_1 :
Na2O 0.48
CaO 0.39
MgO 0.02
P2O5 0.06
TiO2 0.23
Remarks
the copper carbonate of the first glaze. I do not
consider this significant.