Kathy McDonald on sat 23 oct 04
I have always wondered about this firing down process,
I use a Geil downdraft nat gas fired kiln (20 cu ft)
and I always close the damper completely
when the kiln reaches cone 10 and then set the controller to
reignite the kiln when it cools about 300 degrees.
I turn the burners back to about 1/2 at this stage.
I let the kiln cool about 300-400 degrees in increments
,,,and continue the cooling process in gradual decreases until
it reaches about 1200 when I soak it for about 1 hour.
I watch the flame and some parts of this cooling are reduction
...some are oxidizing.
The results are great with iron/dolomite glazes, but sometimes quite
muddy when it comes to glazes like the rutile blues.....
could it be the cooling process that affects these rutile glazes?
Kathy
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of Vince
Pitelka
Sent: Friday, October 22, 2004 8:00 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: fire down
> fire down is always, always, always oxidize.
But Mel, what about John Neely's wonderful pots, produced by reduction
cooling, in other words, firing down in a reduction atmosphere? Be careful
of words like "always."
- Vince
Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
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Earl Brunner on sat 23 oct 04
I know that the firing down process in the electrics at the art center
"kills" cone 6 Floating Blue. You may be right.
Earl Brunner
Las Vegas, NV
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Kathy McDonald
Sent: Saturday, October 23, 2004 6:06 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: fire down, reduction and an additional question
The results are great with iron/dolomite glazes, but sometimes quite
muddy when it comes to glazes like the rutile blues.....
could it be the cooling process that affects these rutile glazes?
Kathy
Ivor and Olive Lewis on sun 24 oct 04
Dear Kathy McDonald,
From memory, I believe the blue colour of Titanium rich glazes is due
to an optical effect that is influenced by the size of the
precipitated crystals. If these are given a chance to grow by
arresting the cooling rate once they have nucleated then the optical
effect will change and the blue colour will disappear.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
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