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Soda
Firing
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firing involves the introduction of a sodium source into the kiln enviroment
at cone 8. The soda combines with the silica, iron, and other elements in
the surface of the wares to produce a glaze or flashed surface. In this
series of slip tests, soda ash was mixed with hot water to create a liquid
solution of soda ash. This solution was poured into a weed sprayer and injected
through holes in the side of the kiln. This takes about 10 minutes and requires
3 pounds of soda ash for this kiln. Any residual soda solution must be rinsed
out for it solidifies upon cooling. A steel brake line tube can be fitted
to the brass tube that comes with the weed sprayer. A compression fitting
is used to attach the two sections of tubing. The steel tube is inserted
into the kiln to about half way into the kiln. The solution is then introduced
into the kiln by squeezing the trigger of the weed sprayer. With a count
of 8, slowly pull the steel tube out to disribute the solution into the
kiln. After the solution is introduced, the kiln continues to fire until
cone 10 is achieved. There are 4 different clay bodies shown below. They
are Aardvark Clay's
Nara Porcelain, Woodfire, and Black Mountain. The last of 4 clays is Grogzilla
from Clay Planet.
The slips were applied on greenware and bisque fired to cone 04. They were
then placed into the kiln for optimal spacing between the soda injection
holes. They were wadded with a 50/50 mixture of kaolin and alumina hydrate.
Wax resist or white glue can be used to hold the wads in place as the pieces
are placed onto the kiln shelves. The burner system is a double blower set
up that fires on 3 pounds of propane pressure. Parts and construction details
can be found in the "Kazegama" link. A clear channel in front
of each burner is left open down each side of the kiln walls in order to
allow flame and heat to travel to the back of the kiln and then over the
top of the wares on the upper shelf. |
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Johnson Flashing
Grolleg 50
EPK 10
Newman Red 10
Nepheline Syenite 30
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Steve's Orange
Grolleg 70
Newman Red 10
Nepheline Syenite 20
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Van
Gilder
Yellow to Gold
EPK 80
Nepheline Syenite 20
Soda Ash 2
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Fake
Avery #5
EPK 74
Newman Red 3
Nepheline Syenite 24
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Slip
#1
EPK 50
OM4 ball clay 50
Borax 6
Zircopax 12.5
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Davis
Red
EPK 70
Carbondale Red 10
Nepheline Syenite 20
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Fake
Avery 2002
McNamee 70
Imco 800 5
Nepheline Syenite 25
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Tan
EPK 50
Taylor ball clay 50
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Smooth
Orange
EPK 40
OM4 ball clay 40
Borax 5
Zircopax 10
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Orange
EPK 35
OM4 ball clay 50
Silica 5
Nepheline Syenite 10
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