Richard Mahaffey on thu 9 aug 07
Mel,
I was talking with Fred Olsen when he mentioned a potter who was getting
fantastic results firing a kiln. He decided to put cone packs all over
his kiln. He found quite a difference in the cones depending on where
in the kiln the cones were placed. Remember the results were
fantastic. He tried everything he could think of to make the cones
everywhere in the kiln bend the same amount. He opened the secondary
air, made the exit flues larger, moved the burners into the burner ports
more then moved them farther back all to no avail. The result of all
of the changes chasing the cones (not the ones he used to fire to but
the ones all over the kiln) was that his glazes stopped working, his
results were no longer fantastic. He ended up selling the kiln to
someone who put it back to it's original condition and started getting
good results right away.
Cones, oxyprobes, pyrometers are all tools not the end all and be all.
The results should be your guide. Sometimes we get a student who can
not stand that the cones are uneven and will try everything to adjust
the kiln to get the cones to be even (open the damper, increase the gas,
oxidize more, reduce more or earlier, or later. When this starts
happening we simply remove one cone pack and fire by the one that is
left - the result is celadons that are green, copper reds that are red,
tenmokus that look like tenmoku glazes, matte glazes that are matte.
The results should be the determining factor not the instruments or
indicators (cones).
YFMV, (your firing may vary)
Rick Mahaffey
Tacoma, WA
Lee Love on fri 10 aug 07
On 8/10/07, Richard Mahaffey wrote:
> Mel,
> I was talking with Fred Olsen when he mentioned a potter who was getting
> fantastic results firing a kiln. He decided to put cone packs all over
> his kiln. He found quite a difference in the cones depending on where
> in the kiln the cones were placed.
Rick,
When I fire a kiln for the first time, I lay out a grid of
test tiles, at least 5 on each level of 3 or 4 levels. Each tile is
glazed with Shino on one side and a strontium red/blue./green glaze on
the other half. Shino tells me about the early reduction while the
strontium tells me how strong later reduction is (it always stays
blue/green unless reduction is very heavy.) It is a way to know the
topography of the kiln. Kiln packs are set with the tiles also.
I like a kiln that has a range of temperatures and
atmospheres. It allows you to fire a variety of glazes in one load.
You just need to know what happens in the various areas of the kiln.
A predictable kiln is good for cookie cutter work, but isn't so
good for innovation.
--
Lee in Mashiko, Japan
Minneapolis, Minnesota USA
http://mashikopots.blogspot.com/
"To affect the quality of the day, that is the highest of arts." -
Henry David Thoreau
"Let the beauty we love be what we do." - Rumi
Rikki Gill on fri 10 aug 07
Hi Everyone,
My never- the- same- temperature- on- the- top- and- bottom, Olsen kiln
leveled out after I sprayed the whole kiln with ITC.
And I must agree that Olsen down drafts are capable of fantastic color.
Best
Rikki Gill
rikigil@sbcglobal.net
www.rikkigillceramics.com
www.berkeleypotters.com
----- Original Message -----
From: "Richard Mahaffey"
To:
Sent: Thursday, August 09, 2007 10:35 PM
Subject: Oxyprobe seeing cones firing results
> Mel,
> I was talking with Fred Olsen when he mentioned a potter who was getting
> fantastic results firing a kiln. He decided to put cone packs all over
> his kiln. He found quite a difference in the cones depending on where
> in the kiln the cones were placed.
Ron Roy on mon 13 aug 07
Hi Rick,
I know Fred and respect him. Any idea how who that potter was and what they
tried to do to get it to fire evenly.
I can imagine some kiln builders would find that thinking advantageous
because they have a hard time building a kiln that does fire evenly. I
think Fred knows how to build that kind.
Frankly - I would think it would be an advantage to have a kiln that fired
evenly - then we could find ways to make it fire unevenly if thats what I
wanted.
RR
>Mel,
>I was talking with Fred Olsen when he mentioned a potter who was getting
>fantastic results firing a kiln. He decided to put cone packs all over
>his kiln. He found quite a difference in the cones depending on where
>in the kiln the cones were placed. Remember the results were
>fantastic. He tried everything he could think of to make the cones
>everywhere in the kiln bend the same amount. He opened the secondary
>air, made the exit flues larger, moved the burners into the burner ports
>more then moved them farther back all to no avail. The result of all
>of the changes chasing the cones (not the ones he used to fire to but
>the ones all over the kiln) was that his glazes stopped working, his
>results were no longer fantastic. He ended up selling the kiln to
>someone who put it back to it's original condition and started getting
>good results right away.
>
>Cones, oxyprobes, pyrometers are all tools not the end all and be all.
>The results should be your guide. Sometimes we get a student who can
>not stand that the cones are uneven and will try everything to adjust
>the kiln to get the cones to be even (open the damper, increase the gas,
>oxidize more, reduce more or earlier, or later. When this starts
>happening we simply remove one cone pack and fire by the one that is
>left - the result is celadons that are green, copper reds that are red,
>tenmokus that look like tenmoku glazes, matte glazes that are matte.
>
>The results should be the determining factor not the instruments or
>indicators (cones).
>
>YFMV, (your firing may vary)
>
>
>Rick Mahaffey
>Tacoma, WA
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
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