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learning to fire the gas....

updated mon 31 mar 97


Talbott on mon 24 mar 97


You are right about the reduction part.. deny oxygen so that the combusting
fuel will seek oxygen from the glaze materials etc... and therefore you get
more metallic glazes and brighter colors vs the oxides of the metals..
Example a bright and shinny penny has a reduced surface, one rather free of
oxygen and the old dull brown penny has an oxidized surface. So you start
with the oxides or other combined form of those elements in most of your
glaze materials and you attempt to reduce them back to their metallic form.

We have a down draft kiln and I increase reduction by pushing the damper in
by degree and by increasing the psi on my burners. So more fuel and less
oxygen creates your reducing atmosphere. I don't alter the size of my two
buner ports which are each approx 5"x5" openings. The barrel of the
burners sets about 3" away from these ports. I seldom go above 3.5 psi and
I use an oxy probe to determine the condition of the kiln's atmosphere. I
usually go into reduction on a glaze fire once the temp has reached 900
Celsius. I keep the oxy probe around .67-.71. Let me know if this
helps... Marshall
------------------------------ original message ----------------------------
>......Now, Marshall, a question or two for thee:
>I have always thought that the object of reduction is to decrease the
>available oxygen supply inside the kiln, thus forcing the fire to seek
>Oxygen in other places (clay body, glaze components) thereby changing the
>colors of some glazes and the claybody itself. Logically, it would
>seem that this would be done by decreasing the primary air and closing
>the damper down a bit.
>I am being taught that I should open the primary air if I close the
>damper. I don't understand why, other than to even out the firing
>temperature overall. I am firing homemade updraft kilns- do you fire
>downdraft kilns differently?
>Lisa Skeen
>Living Tree Pottery
>Greensboro, NC

>the above site can be viewed but is still under construction<

below are other web-sites which mention the exhibit:
{contact me directly for more information}

Celia & Marshall Talbott
Pottery By Celia
Route 114
P.O. Box 4116
Naples, Maine 04055-4116
(207)693-6100 voice and fax

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