reacting Glazes
The background glaze is cooper_404_1Na_Z45_MZn; the inlay desig is glazed with
hiAlk_Z3P_MAl.
The design is created by adhering a mask and then applying the main
glaze. After drying,
The matrix (i.e. background) glaze and inlay glaze do not overlap before
firing. The width of the
The matrix glaze is high in zinc yet contains almost no calcium. It does
contain nickel, whose color
The inlay glaze is high in alumina and contains titanium, resulting in a stiff
glaze with rutile crystals.
For contrast we see the same matrix glaze cooper_404_1Na_Z45_MZn with a
different inlay glaze,
In contrast to what is seen in the prior note, here the matrix glaze has
unhealed blisters, resulting from
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 1850 deg F then a 2 hr hold at 1850 deg F
300 deg F an hour to 1750 deg F then a 1 hr hold at 1750 deg F
300 deg F an hour to 1700 deg F then a 3 hr hold at 1700 deg F
25 deg F an hour to 1650 deg F then a 1 hour hold at 1650 deg F
K2O 0.08
Al2O3 0.41
SiO2 2.4
molecular percent Silica 63.1%
added:
1.5% nickel oxide
K2O 0.12
Al2O3 0.60
SiO2 3.28
molecular percent Silica 63.4%
the mask is removed and the open area filled in with a
second glaze, using a bulb syringe
with a needle applicator.
original inlay varied from an eighth of an inch to
three eighths of an inch.
is highly sensitive to the presence of
calcium. Its surface is covered in needle-shaped zinc crystals.
It is a
micro-crystalline matte glaze featuring two shades of green crystalline
inclusions
in a yellow ground. The blue/green markings are most
prominent where the glaze is thickest.
This inlay glaze contains
calcium. which diffuses into the matrix glaze creating a band of
nickel brown
surrounding the inlay.
oribe-woof-MAlk-PPSi
here.
an overgenerous glaze application. This
glaze is a work in progress, so very sensitive to application thickness.
Close up Images of the interaction region
Image of the piece
bowl with glaze cooper_404_1Na_Z45_MZn and inlay glaze hiAlk_Z3P_MAl
bowl is ~7 inches in diameter
oxidation firing to cone 10 in an electric kiln
Firing profiles
Up Fire profile cone 10
Down Fire Profile cone 10
Clay body is a grolleg porcelain from Clay Art Center in Tacoma, WA.
glaze composition
Empirical Formula cooper_404_1Na_Z45_MZn :
Na2O 0.41
CaO 0.02
MgO 0.01
BaO 0.16
ZnO 0.31
Inlay Glaze:
Empirical Formula hiAlk_Z3P_MAl :
Na2O 0.51
CaO 0.35
MgO 0.02
P2O5 0.06
TiO2 0.22