Gail Dapogny on fri 28 feb 03
Hi Barb,
We fire to cone 10 very soft. When cone 9 is about half over, we start the
soak, turning back both gas and air a bit always maintaining a moderate
reduction flame. We try to hold for 45 minutes to an hour without having
the 10 go over too far. We never go back to oxidation or even a neutral
atmosphere, after reducing since 012. After we turn the kiln off, we close
it up. The kiln has a bricked door and 4 good-sized burner ports, so it is
in oxidation as soon as we turn it off.
If you're getting just a bare wisp, you probably are in neutral. Can you
turn back both your gas and air? With the air turned back somewhat, you
won't have to turn back your gas as much to maintain the temp during the
soak.
Hope this helps.
Gail Dapogny
>Tony or other reduction firers:
>
>This may sound like a given but when you soak at the end of your firing what
>is the atmosphere? To soak our kiln(means holding top temp without
>increasing temp) I have to back the burners to half without moving the
>damper. I don't have an oxyprobe or anything but from seeing it seems to me
>that the kiln is in a neutral if not oxidizing atmosphere. What do you
>think?
>
>Barb Murphy
>Waterloo County Pottery
>Waterloo Ontario
>Canada
Gail Dapogny
1154 Olden Road
Ann Arbor, MI 48103-3005
(734) 665-9816
gdapogny@umich.edu
http://www.silverhawk.com/ex99/dapogny (single historical photo - no longer
registered with Silverhawk)
Dave Murphy on fri 28 feb 03
Tony or other reduction firers:
This may sound like a given but when you soak at the end of your firing what
is the atmosphere? To soak our kiln(means holding top temp without
increasing temp) I have to back the burners to half without moving the
damper. I don't have an oxyprobe or anything but from seeing it seems to me
that the kiln is in a neutral if not oxidizing atmosphere. What do you
think?
Barb Murphy
Waterloo County Pottery
Waterloo Ontario
Canada
Hank Murrow on sat 1 mar 03
On Friday, February 28, 2003, at 08:43 AM, Dave Murphy wrote:
> Tony or other reduction firers:
>
> This may sound like a given but when you soak at the end of your
> firing what
> is the atmosphere? To soak our kiln(means holding top temp without
> increasing temp) I have to back the burners to half without moving the
> damper. I don't have an oxyprobe or anything but from seeing it seems
> to me
> that the kiln is in a neutral if not oxidizing atmosphere. What do you
> think?
Dear Dave;
I started soaking my gas kiln when pursuing those 'curdled white with
firecolor' shinos that I loved from the Momoyama period in Japan. Note
that these are not the american shinos with soda ash. But the soak was
done during the cooling around 1900F, and in OXidation. My theory is
that the iron (or other metals) would crystallize to form a mat surface
with oxidized color response. Indeed, this works a charm with any glaze
that has the potential of developing a micro-crystalline surface. I do
this regularly with my C/10 oxidation glazes.......copper blues and
greens, blacks, copper yellows, rutile/cobalt greens, lithium iron
yellows, etc. The idea is to afford the cooling glaze a long period
(4-8 hours) of time in oxidation, at a temperature where the
crystalline network will grow. Lovers of copper reds......forget this
approach.
Try this sometime, and report back to us.
Cheers, Hank
| |
|
