Janet Kaiser on mon 29 nov 99
Hi David,
I was surprised to hear you saying: >>If you load your kiln with pots that
have been glazed the same day they are much wetter than your kiln shelves
will be.<<
I was always taught to make sure glazed pots were well and truly BONE DRY
before firing. Does your experience mean that is just one more pottery myth?
I would be interested to hear, because I was convinced that some glazing
problems discussed on this list are really due to overlooking this "basic
rule".
As for the original question on wet kiln shelves... I am sure you are right
about a biscuit firing sorting out any problem without any worry.
>If you are really worried, just load the kiln as usual
>and candle a couple of burners for an hour or two.
>Or, fire a bisque firing first. If you start out slow
>enough for a bisque, that will be plenty slow enough
>to make sure the kiln shelves are dry.
Janet Kaiser
The CoA, Criccieth, GB-Wales
http://www.the-coa.org.uk
postbox@the-coa.org.uk
Earl Brunner on tue 30 nov 99
While it is true that some glaze defects are, or may be atributed to placing the
damp ware in a kiln and heating it too rapidly, it is also true that if you know
your clay, know your glazes and their application, that sometimes it doesn't
seem to hurt. I would say that really thick applications (that may crawl
anyway) could be a problem and you can blow up thick bisque (been there, done
that) that is wet by heating it too fast. If you know you have damp ware, and
take a little time at the first with low heat to dry it out it shouldn't be a
problem.
Janet Kaiser wrote:
> ----------------------------Original message----------------------------
> Hi David,
>
> I was surprised to hear you saying: >>If you load your kiln with pots that
> have been glazed the same day they are much wetter than your kiln shelves
> will be.<<
>
> I was always taught to make sure glazed pots were well and truly BONE DRY
> before firing. Does your experience mean that is just one more pottery myth?
> I would be interested to hear, because I was convinced that some glazing
> problems discussed on this list are really due to overlooking this "basic
> rule".
>
> As for the original question on wet kiln shelves... I am sure you are right
> about a biscuit firing sorting out any problem without any worry.
>
> >If you are really worried, just load the kiln as usual
> >and candle a couple of burners for an hour or two.
> >Or, fire a bisque firing first. If you start out slow
> >enough for a bisque, that will be plenty slow enough
> >to make sure the kiln shelves are dry.
>
> Janet Kaiser
> The CoA, Criccieth, GB-Wales
> http://www.the-coa.org.uk
> postbox@the-coa.org.uk
--
Earl Brunner
http://coyote.accessnv.com/bruec
mailto:bruec@anv.net
Ray Aldridge on wed 1 dec 99
At 03:10 PM 11/29/99 EST, you wrote:
>----------------------------Original message----------------------------
>Hi David,
>
>I was surprised to hear you saying: >>If you load your kiln with pots that
>have been glazed the same day they are much wetter than your kiln shelves
>will be.<<
>
>I was always taught to make sure glazed pots were well and truly BONE DRY
>before firing. Does your experience mean that is just one more pottery myth?
>I would be interested to hear, because I was convinced that some glazing
>problems discussed on this list are really due to overlooking this "basic
>rule".
In my opinion, this is one of those pottery myths that are very difficult
to drive a stake through. Perhaps it was because I was always firing just
before a show in the bad old days, but I never had the luxury of letting
glazed pots dry before stacking and firing. In fact, now I glaze in the
evening and fire overnight. But I do candle for a couple of hours before
commencing to fire in earnest. I've never had any glaze flaw that could
reasonably be attributed to this procedure-- in fact, I almost never have
any glaze flaws, because I refuse to use persnickety glazes. Life's too
short. Your mileage may vary.
Ray
Aldridge Porcelain and Stoneware
http://www.goodpots.com
Vince Pitelka on thu 2 dec 99
>I was surprised to hear you saying: >>If you load your kiln with pots that
>have been glazed the same day they are much wetter than your kiln shelves
>will be.<<
>I was always taught to make sure glazed pots were well and truly BONE DRY
>before firing. Does your experience mean that is just one more pottery myth?
>I would be interested to hear, because I was convinced that some glazing
>problems discussed on this list are really due to overlooking this "basic
>rule".
As others have indicated, this is one of those myths. HOWEVER, if you are
firing thick wares that are freshly glazed, it is possible to blow stuff up
if you crank on the heat too quickly. In production many years ago I used
to load the kiln right after glazing, turn the burners on low for fifteen
minutes, and then crank them up pretty high. Never had any problems
associated with firing freshly glazed wares too quickly. I normally did
cone 10 reduction firings in 7 to 8 hours, and the wares came out great. It
wreaked havoc on my silicon carbide kiln shelves, but the wares were fine.
When I closed down the studio to go to grad school in 1985, almost all of
the 40 seven-year-old 14" by 28" shelves were badly cracked. Now I know
better. That's why I like overnight preheats. And that's why I like
high-alumina shelves for cone 10.
Best wishes -
- Vince
Vince Pitelka
Home - vpitelka@DeKalb.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
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