Glaze From a Line Blend
A tile in a line blend between two disparate glazes shows a fascinatingly textured
effect, but only where the glaze is thin.
The glaze with the composition of that tile is reminiscent of the desired
texture, a slight modification gets even closer.
The target tile, #4 from the line blend with left end glaze
longquan_n_song_Z2H_0PSi, and right end glaze iron_8_R_C10_13PSi
0.4 longquan_n_song_Z2H_0PSi + 0.6 iron_8_R_C10_13PSi
and name it longquan_iron_2_3, and its modification longquan_iron_2_3_MZn,
with less ZnO and altered alkali metals.
I show images of the two ends of the line blend, the target tile, with its two
next neighbor tiles, and the two resulting glazes,
The Left end glaze is longquan_n_song_Z2H_0PSi, the Right end glaze is
iron_8_R_C10_13PSi
The glaze with composition that of the target tile, tile 4.
bowl is ~ 4 inches in diameter.
The glaze longquan_iron_2_3 without ZnO, and altered
alkali metal balance.
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 half hour hold at 1750 deg F
300 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 0.14
Al2O3 0.54
SiO2 3.41
molecular percent Silica 68.6%
added .2% SiC
K2O 0.11
Al2O3 0.56
SiO2 3.12
molecular percent Silica 63%
K2O 0.12
Al2O3 0.55
SiO2 3.2
molecular percent Silica 65.2%
K2O 0.22
Al2O3 0.56
SiO2 3.1
molecular percent Silica 63.7%
Only the thin outer edge of tile 4 shows the multiple colored matte crystals,
where thicker, there remains only a
Removing that small bit of Zinc from longquan_iron_2_3 will increase its
viscosity, which most likely shifts
is
comprised of two parts of longquan_n_song_Z2H_0PSi and three parts
iron_8_R_C10_13PSi.
I write that as:
longquan_iron_2_3, and
longquan_iron_2_3_MZn.
The ends of the line blend
the target tile, tile 4, and its two neighbors, tiles 3 and 5
Image of the glaze longquan_iron_2_3
inside
outside
Image of the glaze longquan_iron_2_3_MZn
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
Left end glaze
Empirical Formula longquan_n_song_Z2H_0PSi :
Na2O 0.07
CaO 0.58
MgO 0.12
ZnO 0.09
Fe2O3 0.02
Right end glaze
Empirical Formula iron_8_R_C10_13PSi :
Na2O 0.45
Li2O 0.25
CaO 0.17
MgO 0.02
Fe2O3 0.28
Target tile glaze
Empirical Formula longquan_iron_2_3 :
Na2O 0.30
Li2O 0.15
CaO 0.33
MgO 0.06
ZnO 0.04
Fe2O3 0.17
Modified Target tile glaze
Empirical Formula longquan_iron_2_3_MZn :
Na2O 0.21
Li2O 0.15
CaO 0.34
MgO 0.08
Fe2O3 0.18
Remarks
full gloss black glaze. This is also seen
in the glaze with that tiles composition, longquan_iron_2_3.
the ease with which precipitates form
in the glaze. The alkali metals were shifted to a more equal distribution.
Replacing Na2O with K2O likely also increases viscosity.