LOWELL BAKER on wed 9 may 01
For many years i have been preaching the use of sawdust as a
viable fuel for firing kilns. The interest in a wood fired aesthetic has
made this an even more viable fuel.
The system I have developed over the past twenty-five years is
capable of temperatures above 3000 degrees. Once the sawdust
is turned on (somewhere above red heat) the fuel consumption
averages about twice the capacity of the kiln. A forty foot kiln
would use about 80 cubic feet of sawdust to fire to cone 12. The
heat gain from this burner system is nothing short of remarkable.
Just to see what it would do last week I took the third chamber of
my wood kiln (about 40 ft) from 1800 degrees to 2100 in eight
minutes. I don't know of any reasonable gas burner that will do
that. I need to make it very clear that I am not advocating this kind
of heat gain, as I don't advocate driving a race car on the street.
This is simply a test case.
My point is the fuel is, for all practical purposed, waste which
means it is probably free. I could fire my kiln almost continually
from the waste sawdust from a local cabinet shop. The burner is
relative simple to build and the cost is about what you would pay
for a gas burner system. Sure there is some effort involved in
getting and storing the sawdust, but I assure you it is less than
wood. My fuel is split into pieces 1/16x1/16 inch, from the factory.
My kiln is a multi-fuel situation. I candle over night with gas; stoke
with wood for ash and blast it with sawdust for heat. When it gets
too hot (above cone 12) I stoke with wood for color and ash and to
cool the kiln somewhat. Once it cools down to about cone 10, I
take it back up with the sawdust to the cone 12, range. I bounce
the kiln back and forth in this heat range as long as I choose. The
stoking is done by filling the hopper every fifteen minutes and
sitting back in a lawn chair and watching the fire.
If you want to add additional ash or salt you can do it by mixing it
with the sawdust.
I do understand this is not the most romantic way to fire with wood
but it does work,and the product, if that's what we are looking for is
indestinguishable from a REAL wood firing.
What are the drawbacks? It is either on or off,and whenb it is on
the least you will get out of a burner is in the neighborhood of
1,000,000 btu. There is some smoke below 1800 degrees. There
is some fly ash (minimal). The fuel requires some special handling
arrangements. You have to build the burner system or have it built.
There is an occasional clog in the system. The static electricity
must be attended to through proper grounding.
I am working on a new kiln that will give me Anagama results in
about three hours. I know. Its not a real wood kiln.
W. Lowell Baker
the University of Alabama
Jeff Lawrence on fri 11 may 01
Lowell Baker was talking about sawdust as a viable and environmentally =3D
friendly wood fuel.
Hello Lowell,
Thanks for sharing your experience with sawdust. Your observations =3D
stimulated a number of questions which I'd enjoy hearing your comments =3D
on.=3D20
1. There are many sawmills around here but the sawdust they would =3D
cheerfully deliver is from green logs, not the (probably) kiln-dried =3D
stuff you get from your cabinet shop. Have you tried less seasoned =3D
sawdust?
2. Have you ever tried an auger (as in a pellet stove) for continuous =3D
fuel feed?
3. Why doesn't the sawdust leave ash? does it just burn too completely =3D
or is it because it isn't really wood?
Best,
Jeff
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