Increasing Iron
The effect of increasing Iron
A glaze comprised of a glassy matrix with micro-crystalline islands,
jingdezhen-iron-3-7, is transformed
Iron is amphoteric in cone 10 glazes, meaning it can function as either a flux
or a network former. Silica is the
jingdeahen-iron-3-7 is an 'interesting' glaze, yet the glassy matrix is
crazed, and the micro-crystalline
jingdezhen-iron-3-7-PFe also has higher phosphorus than jingdezhen-iron-3-7,
however I do not think this
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 1750 deg F then a 50 min 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 66.2%
K2O 0.10
Al2O3 0.61
SiO2 3.5
molecular percent Silica 64.9%
into a uniform variegated melt,
jingdezhen-iron-3-7-PFe, by a significant increase in Iron.
primary network former in ceramic
glazes. At cone 10, iron can behave as does silica. As increasing
silica,
so also increasing iron, can have the effect seen here, of
producing a more uniform melt.
islands are not sufficiently spectacular in
themselves to make up for that crazing.
is a significant part of the difference
between these two glazes.
Image of the low iron glaze jingdezhen-iron-3-7
inside
outside
Image of the high iron glaze jingdezhen-iron-3-7-PFe
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