a high alkaline iron glaze in six firings
The glaze, hiAlk_satIron in other flavors is
By adjusting the down-fire holds, in six firings, this high alkali metal, high
iron glaze containing titanium
The design is a slip trailed contrast glaze applied first to the bisque,
subsequently followed
All four firings have the same up-fire protocol.
Firing 1:
No holds - a baseline firing.
Firing 2:
In the down-fire, there is one four hour hold at 1900 degF.
Firing 3:
In the down-fire, there is one four hour hold at 1650 degF.
Firing 4:
In the down-fire, there is one four hour hold at 1750 degF.
Firing 5:
In the down-fire, there is one four hour hold at 1900 degF followed by a four
hour hold at 1650 degF.
Firing 6:
In the down-fire, there is one four hour hold at 1650 degF followed by a four
hour hold at 1900 degF.
The bowls are 5 to 6 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
Turn off kiln.
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 1900 deg F then a 4 hr hold at 1900 deg F
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 1650 deg F then a 4 hr hold at 1650 deg F
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 4 hr hold at 1750 deg F
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 1900 deg F then a 4 hr hold at 1900 deg F
400 deg F an hour to 1650 deg F then a 4 hr hold at 1650 deg F
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 1650 deg F then a 4 hr hold at 1650 deg F
400 deg F an hour to 1900 deg F then a 4 hr hold at 1900 deg F
K2O 0.06
Al2O3 0.56
SiO2 3.67
molecular percent Silica 66%
Note that the result in the Firing #2 with a 4 hour hold at 1900 degF is nearly
the same as in Firing #1 with
shown here .
emerges with noticeable differences. It
can appear as:
mottled tan and black with gold highlights
nearly uniform mustard with minor black, orange and gold markings
dramatic mixed black and orange with gold bubbles surrounded in red
bright yellow-y orange with white red and gold markings
by application of the matrix glaze. It is mostly
washed out as the design glaze also contains titanium.
Image of the glaze hiAlk_satIron in Firing 1
Image of the glaze hiAlk_satIron in Firing 2
Image of the glaze hiAlk_satIron in Firing 3
Image of the glaze hiAlk_satIron in Firing 4
Image of the glaze hiAlk_satIron in Firing 5
Image of the glaze hiAlk_satIron in Firing 6
oxidation firing to cone 10 in an electric kiln
Firing profiles
Firing 1 profile
Up Fire profile cone 10
Down Fire Profile cone 10
Firing 2 profile
Up Fire profile cone 10
Down Fire Profile cone 10
Firing 3 profile
Up Fire profile cone 10
Down Fire Profile cone 10
Firing 4 profile
Up Fire profile cone 10
Down Fire Profile cone 10
Firing 5 profile
Up Fire profile cone 10
Down Fire Profile cone 10
Firing 6 profile
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_satIron:
Na2O 0.62
CaO 0.29
MgO 0.03
Fe2O3 0.10
P2O2 0.08
TiO2 0.15
Remarks
no holds. Yet the results in Firing #6
with a four hour hold at 1650 degF followed by a four hour hold at 1900 degF
is rather different from the results in Firing #3 with only the four hour hold
at 1650 degF.
That hold at 1900 degF makes a significant difference only if
preceeded by a hold at 1650 degF.