New Glazes from Old - substituting for Lithium
The glaze jingdezhen-iron-7-3-MLi-0 is derived from the glaze
jingdezhen-iron-7-13 by
The glaze alex_mashiko_Imerys_Z3H is derived from alex_mashiko_Imerys by
substituting sodium oxide/potassium oxide
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 0.59
SiO2 3.5
molecular percent Silica 65.9%
K2O 0.22
Al2O3 0.60
SiO2 3.52
molecular percent Silica 66%
K2O 0.08
Al2O3 0.62
SiO2 3.95
molecular percent Silica 66.2%
K2O 0.06
Al2O3 0.63
SiO2 3.07
molecular percent Silica 60.3%
substituting a combination of sodium oxide and
potassium oxide for the lithium oxide. In addition to a shift in colors,
the new glaze has lost it dusting of coppery metallic crystals. It is also a
more viscous glaze.
This is most easily observed in the frothy mass of
unhealed bubbles on the inside of the small test bowl,
where the glaze
application was unduly thick.
for lithium oxide, and in
addition lowering the silica to partially accommodate the lower fluxing power
of the
other alkali metal oxides. Without lithium, and with
substantially less silica, the new glaze is
more interesting. It has a
brighter color, and a dense covering of copper-colored metallic crystals.
Image of the glaze jingdezhen-iron-7-13
inside
outside
bowl is ~3 inches in diameter
Image of the glaze jingdezhen-iron-7-13-MLi-0 non lithium version
inside
outside
bowl is ~3 inches in diameter
Image of the glaze alex_mashiko_Imerys
section of a plate to avoid distracting decoration
Image of the glaze alex_mashiko_Imerys_Z3H non lithium version
inside
outside
bowl is ~3 inches in diameter
oxidation firing to cone 10 in an electric kiln
Firing profiles
Up Fire profiles
Up Fire profile
Down Fire Profile
Clay body is a grolleg porcelain from Tacoma Clay Art Center.
glaze compositions
Empirical Formula jingdezhen-iron-7-13 :
Na2O 0.33
Li2O 0.16
CaO 0.34
MgO 0.07
Fe2O3 0.17
P2O5 0.05
Empirical Formula jingdezhen-iron-7-13-MLi-0 :
Na2O 0.38
CaO 0.34
MgO 0.06
Fe2O3 0.17
P2O5 0.05
Empirical Formula alex_mashiko_Imerys :
Na2O 0.16
Li2O 0.24
CaO 0.46
MgO 0.06
Fe2O3 0.26
P2O5 0.13
Empirical Formula alex_mashiko_Imerys_Z3H :
Na2O 0.40
CaO 0.52
MgO 0.02
Fe2O3 0.25
P2O5 0.15