Shino
cone 10 oxidation
Firing profile
Up Fire profile
150 deg F an hour to 250 deg F
400 deg F an hour to 2050 deg F
120 deg F an hour to 2250 deg F
60 deg F an hour to 2310 deg F with a hold of 20 minutes at 2310 deg F
Down Fire Profile
A half hour hold at 1750 deg F
A three hour hold at 1700 deg F
slow downfire at 25 deg F an hour in the interval 1700 deg F to 1650 deg F
A one hour hold at 1650 deg F
The cones show this as a hot cone 10 firing.
These glazes are derived from The glaze sh_ZJ_2 seen here:
These are shino glazes, the glaze sh_ZJ_2 from which these are derived had a
small amount of iron added to the glaze, as these glazes
are fired on a
porcelain body.
To get the more varied colors which result from allowing the glaze to pull the
iron
out of an iron bearing slip or clay body, the new glazes derived
from sh_ZJ_2 contain no iron, but are applied over a redart clay slip.
I was encouraged by the texture of my first attempt, sh_ZJ_2PAlSi, which has higher Alumina and Silica than sh_ZJ_2, however I wanted less gloss.
sh_ZJ_2PAl has more alumina, but the same silica as sh_ZJ_2, sh_ZJ_2PSi has the same alumina, but more silica than sh_ZJ_2.
Clay body is a grolleg porcelain from Tacoma Clay Art Center.
glaze composition of the three glazes
Emperical Formula sh_ZJ_2PAlSi:
K2O 0.08
Na2O 0.33
Li2O 0.5
CaO 0.05
MgO 0.04
Al2O3 1.4
SiO2 3.76
molecular percent Silica 61 %
Emperical Formula sh_ZJ_2PAl:
K2O 0.08
Na2O 0.31
Li2O 0.52
CaO 0.05
MgO 0.04
Al2O3 1.45
SiO2 3.5
molecular percent Silica 59 %
Emperical Formula sh_ZJ_2PSi:
K2O 0.08
Na2O 0.32
Li2O 0.51
CaO 0.05
MgO 0.04
Al2O3 1.32
SiO2 3.7j5
molecular percent Silica 62 %
These glazes are higher in Lithium than I have found possible in glazes with lower alumina.
The bowls are ~ 4 inches in diameter.
The glaze is shown on the inside and outside, resp left and right
glaze sh_ZJ_2PAlSi
 |
 |
glaze sh_ZJ_2PAl
 |
 |
glaze sh_ZJ_2PSi
 |
 |
Remarks
These glazes likely will have stronger color with a thicker layer of the
redart clay slip. sh_ZJ_2PAl and sh_ZJ_2PSi have
a slightly thicker layer of
redart clay applied to the bisque than does sh_ZJ_2PAlSi.
sh_ZJ_2PSi has a good texture, yet seems unlikely to develop varied colors.
sh_ZJ_2PAl has strong and varied colors, yet is sufficiently underfired that its blistered and feels like sandpaper.
This is work in progress, next is still higher lithium, and more iron beneath the glaze.