Avril Farley on thu 29 jul 04
Bill Scran Said......."Want to
get there at 350/500 °F per hour (I fire from start to cone 6 in 3-4 hours).
Then crash cool to about 200°F below top temp (could be more or less
depending on glaze) and hold at that temp for desired length of time."
This is incredibly fast firing - does your clay mature properly at these
temperatures without bloating?, and what size is the kiln, and how does this
speed affect the elements? I rarely fire at more than 130 per hour to 950
in my 4.5 cu ft Olympic toploader, and then as fast as possible thereafter
to top temp before doing the cooling bit I have no trouble achieving
crystals of any size at this rate, and my last set of elements did 60+
firings.
Avril in the Forest of Dean UK
william schran on thu 29 jul 04
Avril wrote:>This is incredibly fast firing - does your clay mature
properly at these
temperatures without bloating?, and what size is the kiln, and how does this
speed affect the elements?<
I actually use a cone 10 white clay called Bee Mix by Aardvark Clay,
I believe it's a porcelainous stoneware. It's lots more forgiving
during the working stages than porcelain. I elected to work with cone
10 clay, even though I fire to cone 6, in an attempt to avoid too
much interaction between clay & glaze and thus avoid excess alumina
from entering the glaze. I consider my work non-functional.
The kiln is an L&L J18X, top loading electric, 3 sections, about 4
cu. ft. I would think, given all the talk about wear of elements
with soaking, a fast firing would actually save element life. Of
course we then deal with long holding temperatures not much lower
than the maturing temp.
Don't know how long the elements will last. I've done about 30
firings with this set and have not noticed much lengthening in the
firing cycle yet.
Fara Shimbo had mentioned she gets about 20-30 firings out of a set
of elements, but she fires higher and replaces the elements when the
end of the firing cycle becomes too long.
Bill
Ilene Mahler on thu 29 jul 04
also fire to 10 and do a 6+ hour soak and this time only 18 firings
usually 20-22. actually waiting for new elements so when I can start to work
I'll be ready..Ilene in Conn
----- Original Message -----
From: "william schran"
To:
Sent: Thursday, July 29, 2004 8:44 AM
Subject: Re: crystalline glazes & Alumina plus speed firing
> Avril wrote:>This is incredibly fast firing - does your clay mature
> properly at these
> temperatures without bloating?, and what size is the kiln, and how does
this
> speed affect the elements?<
>
> I actually use a cone 10 white clay called Bee Mix by Aardvark Clay,
> I believe it's a porcelainous stoneware. It's lots more forgiving
> during the working stages than porcelain. I elected to work with cone
> 10 clay, even though I fire to cone 6, in an attempt to avoid too
> much interaction between clay & glaze and thus avoid excess alumina
> from entering the glaze. I consider my work non-functional.
>
> The kiln is an L&L J18X, top loading electric, 3 sections, about 4
> cu. ft. I would think, given all the talk about wear of elements
> with soaking, a fast firing would actually save element life. Of
> course we then deal with long holding temperatures not much lower
> than the maturing temp.
> Don't know how long the elements will last. I've done about 30
> firings with this set and have not noticed much lengthening in the
> firing cycle yet.
>
> Fara Shimbo had mentioned she gets about 20-30 firings out of a set
> of elements, but she fires higher and replaces the elements when the
> end of the firing cycle becomes too long.
>
> Bill
>
>
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