LOWELL BAKER on thu 5 jul 01
I just opened the door of the first firing of the University of Alabama
cast sawdust fired soda kiln. The results exceed my rather high
espectations.
The kiln was cast using about 4000 pounds of donated castable
refractory material. The form was built from scrap wood from my
neighbor's shed and the labor was student and me. Abstractly
speaking the cost to build this kiln was $0. It took me about three
6 hours to build the forms and was spent about ten hours mixing
and casting the kiln.
The floor is a single cast unit which contains the flue and a 3" dia.
sawdust tube manifold with two port openings into the firing
chamber. The flue was cast as a unit, connected to the kiln. I
expected some cracks but got almost none in the first firing. this
kiln has no bagwall the fire is directed upward by the manifold.
The form of the kiln is cantenary and at this point has no metal
structure. I will add this later, after I get several insulation coats on
the kiln.
We tore the forms out over the weekend and stacked the kiln with
the end to the term student work on Monday. I placed a venturi
burner into the manifold on Monday afternoon and fired it all night to
warm the kiln and burn out the remainder of the PVC tubing that
formed the manifold. I won't use PVC again it was an awful burnout
experience.
We used the burner to bring the kiln up to about 1200 degrees (the
limit of that burner on that kiln). At that point we attached the
sawdust burner with a 2" feed tube. We fired for about an hour and
a half, taking the temperature up to about 2000 degrees. At about
5:00 we replaced the two inch tube with three inch tube and
immediately shot up to cone 11. We added about three pounds of
soda ash to the sawdust over the last hour of firing.
The results were a nice light brown color in the clay,a very
sparkling finish to the salt and good glaze color. I can't wait to get
my work into this little kiln.
I just learned that I will be presenting information on the burner
system in a half hour session at NCECA next year.
I will be off the list for the next month. If any of you want more
information or images of the kiln and firing, write me directly at
Wbaker@ART.as.ua.edu and I will resopnd to you when I return
from the high country.
W. Lowell Baker
The University of Alabama
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