On 24 Jul 2003 15:22:15 -0700, (L.Mac) wrote:

I am very concerned about the noises I heard. I noticed popping and
crackling when I opened the lid at around 100 F. I closed the lid and
waited a while. I eventually unloaded at 92 F. I can't imagine that
the noises are from cooling too fast except that the outside temp was
cooler than the kiln temp but other than that the kiln had been
cooling for 36 hours. It seems as though my temp readout and the
actual temp don't agree b/c the kiln fired hotter than it should have
(the 7 cone melted) but the readout was correct for ^6. I didn't have
a problem with the bisque fire so I wasn't expecting any problems with
the glaze fire----as far as temp goes anyways. I used the cones for
good measure, but I didn't check them like I should----LESSON LEARNED.
Anyways, does anyone know what the noises are?
LMac

If the noise is coming from the pieces themselves, then it is
probably crazing. You may continue to hear it long after
the pieces are cool, if the glaze expansion is too great for
the body. (I have heard it up to 24 hours later, by which time
it had slowed down to one "tink" every hour or so.) You will
be able to see fine crazing lines under a magnifier. A 20x
microscope is wonderful if you have it, otherwise a hand
lens or even your naked eye under a good light.

If the noise was coming only from the kiln, it was
probably just the blast of cool air causing sudden shrinkage
in all sorts of places in the kiln itself.

I like to wait over night and unload the next morning.
It feels like I'm a kid at Christmas again!


Bob Masta
dqatechATdaqartaDOTcom

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