Glaze Reactions
Yet another titanium microcrystalline matte glaze, hiAlk_Z3P_Z4E_0; Again, the
inlay design is
Prior examples of this inlay glaze
are seen with high titanium matrix glazes
Here, the background glaze has a bit less silica than the most recent glaze
seen, hiAlk_Z3P_Z4E; the snow
The black band of rutile crystal clusters seen in prior examples is gone, and
with it the diffuse amber halo.
There are many intact crystals in the interaction region. Additionally,
there are many
The matrix (i.e., background) glaze and inlay glaze overlap minimally before
firing. The width of the
The design is created by adhering a mask and then applying the main
glaze. After drying,
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 0.10
Al2O3 0.58
SiO2 2.99
molecular percent Silica 61.7%
K2O 0.10
Al2O3 0.35
SiO2 3.29
molecular percent Silica 70.58%
Added:
5.0% Copper Oxide
Regarding the formation of the various band of color surrounding the inlay
within the matrix glaze:
Copper oxide diffuses from the inlay into the matrix glaze, and titanium oxide
diffuses in the other
The titanium crystals that had already formed in the matrix glaze absorb the
copper that diffuses
glazed with oribe-woof-PAl-PSiMg.
hiAlk_Z3P_Z4A: ,
hiAlk_Z3P_Z4A_PF and
hiAlk_Z3P_Z4A_PF .
flakes nearly merge, so we have a 'tween
glaze. One more inlay like none of those seen previously. Again,
the
form of inlay and interaction regions are rather close to that of the
mask that was used to make them
because the inlay has spread little, yet
the interaction region contains a greater variety of artifacts,
and again
displays the large grey rutile micro-crystalline clusters.
Now we find a rather broad brownish band
strong in color which fades into the background.
relics of crystal clusters, yet the flow
patterns of various second phase liquids that were formed
within the
interaction region are also present.
original inlay varied from an eighth of an inch to
three eighths of an inch.
the mask is removed and the open area filled in with a
second glaze, using a bulb syringe
with a needle applicator.
Close up Images of the interaction region
Image of the piece
bowl with glaze hiAlk_Z3P_Z4E_0 and inlay oribe-woof-PAl-PSiMg
bowl is ~6 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 hiAlk_Z3P_Z4E_0 :
Na2O 0.48
CaO 0.40
MgO 0.02
P2O5 0.06
TiO5 0.21
Inlay Glaze:
Empirical Formula oribe-woof-PAl-PSiMg:
Na2O 0.04
CaO 0.61
MgO 0.25
P2O5 0.01
Remarks
direction into the inlay glaze. As the inlay glaze
cools, the quantity of titanium it can dissolve decreases,
and therefore
the titanium that had diffused into the inlay glaze precipitates and forms
that white fringe
surrounding the inlay.
into the matrix glaze. The whitish fringe has brown
flecks - did it form sufficiently early that it
took up some copper? Had
something else diffused beyond the copper and titanium?