Keith Arbogast on sat 25 mar 06
Dear John Hesselberth et al;
Is the cone 6 firing cycle you described in your "2004 NCECA
Presentation" also suitable for bisque? That is, up to the
appropriate heat-work for cone 04 or cone 06. If not, would you
please describe one?
With my thanks,
Keith Arbogast
Bloomington, Indiana
John Hesselberth on sun 26 mar 06
On Mar 25, 2006, at 3:28 PM, Keith Arbogast wrote:
> Is the cone 6 firing cycle you described in your "2004 NCECA
> Presentation" also suitable for bisque? That is, up to the
> appropriate heat-work for cone 04 or cone 06. If not, would you
> please describe one?
Hi Keith,
The short answer to your question is: No.
Bisque firings need to be SLOOOW, at least in the early stages. I
usually take it up at about 100F/hour to 200F and let is soak there
for an hour or two. That's to make sure all the free water is gone
and that the pots are really dry. Then I go up at 150F/hr to 800F.
Combined water should be gone at 800. I then speed up to 300F/hr
until 1800 or so and slow down for the last hundred degrees--again to
100F/hr. I also soak for 20 minutes at peak temperature. This is
particularly important to make sure ALL of the pots--even the ones at
the bottom of a stack of 3 or 4--get up to temperature.
I just shut the kiln off after the 20 minute soak at peak
temperature. There's no need to control the cooling rate on bisque.
I'm sure there are a zillion variants of this that would work, but
the key is slow and easy. Don't rush bisque firings. You want to be
sure that anything and everything that can decompose and give off gas
at temperatures up to and including your bisque temperature has the
time to do so.
Regards,
John
| |
|
