Dave Finkelnburg on sun 26 mar 06
Keith,
Just to add briefly to John Hesselberth's
excellent post, his soak at 200F is intended to dry
out any remaining free water at a temperature LESS
THAN the boiling point of water. Emphasis is mine,
intended to point out how important it is to "candle"
or heat the ware in the kiln at a low enough
temperature to guarantee you won't damage anything
from a steam explosion.
Yes, I have learned this the hard way. Vacuuming
bits of shattered clay out of kiln elements is a good
way to understand the importance of this fundamental.
:-(
Where John lives the elevation is very near sea
level and water boils at 212F. Here I live at
4,750-feet elevation, and water boils at ~203F. I
think it's a good idea to "candle" the kiln about 15
to 25-degrees below the boiling point of water AT THE
KILN SITE. This allows for kiln temperature
fluctuation and thermocouple inaccuracy.
To know what your thermocouople displays at the
boiling point of water where you live, just put the
tip of the thermocouple into boiling water until the
reading stabilizes. Then candle safely below that
temperature.
Clay presents enough frustrations without blowing
up greenware! :-)
Good potting,
Dave Finkelnburg
--- John Hesselberth wrote:
> 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.
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Keith Arbogast on mon 27 mar 06
Hi John and Dave,
Thank you for the detailed answers. They will be a tremendous help to
us.
With my best wishes,
Keith Arbogast
Bloomington, IN
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