Dannon Rhudy on thu 15 jan 98
.......do you call it reduction if there is flame showing at the
spyholes.....
The answer to that question is not so simple as one might think.
One can have a flame at all spy holes and out the flue and
everywhere, I guess, without having a reducing atmosphere inside
the kiln. And the COLOR of the flame is important. If you are
firing an updraft kiln, without gauges other than your eyes, ears,
and nose, then:
You would look for an orange flame at the flue, and at the
upper and lower spy holes. I prefer a slow, licking flame at
the spy holes, usually 6-10" long. The flame out the flue will
be a bit harder, usually. When I first put the kiln into
reduction at about ^010, the flame is shorter, softer, but
still orange. You may or may not want to keep it in light
reduction the rest of the way to temperature, depending upon
the glazes inside. The flame will grow harder as the kiln gets
hotter, and adjusment of the damper will be necessary. I do
not like to have visible smoke when I reduce, and never do.
Nonetheless, I get reliable copper reds and shinos; generally
they are a good indicator of whether or not reduction was
sufficient and timely. Both the sound and the smell of the
kiln are different in reduction than oxidation, and I use those
clues, too. It will take some experience to note these
differences, and I can't think of a way to describe them.
Well - maybe the sound is a bit throatier in reduction, but
that is a pretty illusive description. I've done a lot of firing
without any gauges other than a lever on the gas line to increase
the flow of fuel, and one learns as one goes.
Now, having said all that, I realize I don't know what your
fuel source is. I assumed gas, but maybe you're firing with
wood. Or coal, or oil, or......
Dannon Rhudy
potter@koyote.com
----------------------------Original
message----------------------------
hi all just a quickie for those who have medium sized brick kilns
[30-75cuft]
need to see it from the flue as well..i know there are many
answers to this
question but i am interested in an average of responses..the
question is
how do YOU judge your kiln to be reducing???
cheers :)
Ray Carlton
Dave Eitel on fri 16 jan 98
For about 18 years I fired using all the sight, smell, sound indicators for
reduction. There were many good firings, a few great ones and a not
insignificant number of aesthetic disasters. Then I bought an oxygen
probe. After some experimentation I found a firing cycle I liked and when
I stick to it I get good to excellent results every time. The probe lets
me achieve repeatable results from one firing to the next. I think it was
well worth the considerable cost.
Dave Eitel
Cedar Creek Pottery
Cedarburg, WI USA
http://www.cedarcreekpottery.com
Stephen Mills on sat 17 jan 98
Oxy probes were not about when I started in full time production. I kept
a graph on acetate of my best firing and overlaying it on the current
firing graph matched the gas and flue settings and the rate of climb,
worked very well indeed giving me consistant results all the way. I
never found any need to change.
Steve
Bath
UK
In message , Dave Eitel writes
>----------------------------Original message----------------------------
>
>For about 18 years I fired using all the sight, smell, sound indicators for
>reduction. There were many good firings, a few great ones and a not
>insignificant number of aesthetic disasters. Then I bought an oxygen
>probe. After some experimentation I found a firing cycle I liked and when
>I stick to it I get good to excellent results every time. The probe lets
>me achieve repeatable results from one firing to the next. I think it was
>well worth the considerable cost.
>
>Dave Eitel
>Cedar Creek Pottery
>Cedarburg, WI USA
>http://www.cedarcreekpottery.com
>
--
Steve Mills
Bath
UK
home e-mail: stevemills@mudslinger.demon.co.uk
work e-mail: stevemills@bathpotters.demon.co.uk
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