iron colors in simplified firings
An exploration of the effect of holds in the down-fire of a saturated iron
glaze.
In prior work, in a complex firing with many downfire holds
this is the glaze, wisskirchen-crystals-PAl:
Now, I wish to see the effects of the individual holds.
I fired this glaze, wisskirchen-crystals-PAl in four distinct firings, one
with no holds, the others
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.
The bowls are ~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
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
K2O 0.10
Al2O3 0.55
SiO2 3.45
molecular percent Silica 64.6%
I have now fired this glaze with 9 distinct downfire protocols and it is
different
inside and
outside .
with only one down-hold. The down-fire holds
were all of the same four-hour duration, but occured
at different
temperatures.
Image of the glaze wisskirchen-crystals-PAl in Firing 1
Image of the glaze wisskirchen-crystals-PAl in Firing 2
Image of the glaze wisskirchen-crystals-PAl in Firing 3
Image of the glaze wisskirchen-crystals-PAl in Firing 4
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
Clay body is a grolleg porcelain from Clay Art Center in Tacoma, WA.
glaze composition
Empirical Formula wisskirchen-crystals-PAl:
Na2O 0.24
CaO 0.62
MgO 0.04
Fe2O3 0.31
TiO2 0.03
Remarks
in all of them.
