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cone accuracy in vapor atmosphere

updated sat 19 jan 02

 

Hank Murrow on thu 17 jan 02


>craig edwards wrote:
>
>'Those of us that fire with wood can have some pretty interesting
>looking cones after they have been subjected to the fly ash and other
>atmospheres that can happen in a wood firing. Some are bloated, discolored
>and basically glazed over with ash etc.
>I wonder what temperature or Cone is actually achieved.'
>
>i have heard, and believed, the claim that cones don't melt accurately once
>salt or soda is introduced to a kiln. i suppose this would also be true at
>some point duirng a wood-firing. would anyone comment on how, and how much,
>their accuracy is affected in salt and/or wood firing? generally salt-firers
>toss salt in once the kiln is near top temp. but ash is in a wood kiln from
>beginning to end. if ash affects cones like sodium vapor does, i suppose the
>effect starts once the kiln is hot enough to melt the ash on the cones?
>
>brian
>
And Hank weighs in;

I've fired the same bodies in my fiberkiln, a salt kiln, and an
anagama. I know that salt affects the cones, and normally fire to C/11-12
to get the same maturity for my clays. In the anagama, I imagine that wood
ash being mostly calcium, would flux the cones. Generally, the kiln I fire
in is taken to C/12-14, with the clay reaching the same maturity as in my
C/10 gas fires. "Your Mileage May Vary....."

Regards, Hank in Eugene

Brian Molanphy on thu 17 jan 02


craig edwards wrote:

'Those of us that fire with wood can have some pretty interesting
looking cones after they have been subjected to the fly ash and other
atmospheres that can happen in a wood firing. Some are bloated, discolored
and basically glazed over with ash etc.
I wonder what temperature or Cone is actually achieved.'

i have heard, and believed, the claim that cones don't melt accurately once
salt or soda is introduced to a kiln. i suppose this would also be true at
some point duirng a wood-firing. would anyone comment on how, and how much,
their accuracy is affected in salt and/or wood firing? generally salt-firers
toss salt in once the kiln is near top temp. but ash is in a wood kiln from
beginning to end. if ash affects cones like sodium vapor does, i suppose the
effect starts once the kiln is hot enough to melt the ash on the cones?

brian

Roger Korn on fri 18 jan 02


Ahhhaaa! So that's why my grolleg porcelain that's translucent at ^12 in the
anagama has gone slumpy
and bloated at ^12 in the reduction fibre kiln.

Now to try some tests with the (AZ) local limestones as fluxes in porcelain instead
of talc at ^6-8...

Roger

Hank Murrow wrote:

> ...
> And Hank weighs in;
>
> I've fired the same bodies in my fiberkiln, a salt kiln, and an
> anagama. I know that salt affects the cones, and normally fire to C/11-12
> to get the same maturity for my clays. In the anagama, I imagine that wood
> ash being mostly calcium, would flux the cones. Generally, the kiln I fire
> in is taken to C/12-14, with the clay reaching the same maturity as in my
> C/10 gas fires. "Your Mileage May Vary....."
>
> Regards, Hank in Eugene
>
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--
Roger Korn
McKay Creek Ceramics
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