Increased Iron and silica
A progression of three glazes.
Three glazes with nearly the same bases, i.e. first column oxides in their
empirical formulae. The second
The first glaze, jingdezhen-iron-3-7, is a bottle brown glassy matrix with
an emerging mixed brown and yellow
The second glaze, jingdezhen-iron-3-7-PFe, is a full gloss variegated glaze with
mixed iron colors, predominantly
The third glaze, jingdezhen-iron-3-7-PFeSi, is as the second, a full gloss
variegated glaze with mixed iron
The second glaze was derived from the first by increasing red iron oxide in
the glaze recipe, then normalizing
bowl is ~ 4 inches in diameter.
bowl is ~ 4 inches in diameter.
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 1800 deg F then a 2 hr hold at 1800 deg F
300 deg F an hour to 1750 deg F then a 1 hr hold at 1750 deg F
50 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 0.60
SiO2 3.48
molecular percent Silica 66%
K2O 0.10
Al2O3 0.61
SiO2 3.5
molecular percent Silica 65%
K2O 0.10
Al2O3 0.61
SiO2 3.95
molecular percent Silica 67.4%
glaze has higher iron oxide than the first,
and the third higher silica than the second.
microcrystalline matte second phase.
orange and a bluish green.
colors, though the dominant color is an
iron red.
the recipe to 100. The third glaze,
similarly, was derived from the second by increasing the silica in the glaze
recipe then normalizing to 100. The normalization shifts the values of the
oxides in the empirical formulae.
Image of the glaze jingdezhen-iron-3-7
inside
outside
Image of the glaze jingdezhen-iron-3-7-PFe
inside
outside
Image of the glaze jingdezhen-iron-3-7-PFeSi
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 jingdezhen-iron-3-7 :
Na2O 0.38
Li2O 0.16
CaO 0.29
MgO 0.07
Fe2O3 0.15
P2O5 0.03
Empirical Formula jingdezhen-iron-3-7-PFe :
Na2O 0.39
Li2O 0.16
CaO 0.28
MgO 0.07
Fe2O3 0.23
P2O5 0.05
Empirical Formula jingdezhen-iron-3-7-PFeSi :
Na2O 0.39
Li2O 0.17
CaO 0.28
MgO 0.06
Fe2O3 0.25
P2O5 0.05