Dave Finkelnburg on wed 17 sep 03
Chris,
I NEVER disagree with you! :-)
In this case you make an excellent, excellent point. The definitive
answer below is taken from the Archives, February 28, 2002, when Tim still
worked for Orton.
Dave, hoping you are well and safe from the weather
"The opinion used by the people at Orton is that if the cone comes within
approximately 300 degrees F of the end point of that cone, it should not be
reused. The heatwork that has taken place can affect the true end point of
the cone. It might take a higher temperature to finally bend that cone
which would result in an overfiring.
My opinion is that if the firing went beyond 1,063 degrees F (quartz
inversion), I would replace all of the cones just as a safety factor. I
definitely would replace the cone or bar in the kiln-sitter. Cones are not
that expensive ( I have to buy mine even though I work here) and I would
rather be safe than sorry.
Best regards,
Tim Frederich
----- Original Message -----
From: "Chris Schafale"
> I ALWAYS agree with Dave F. -- Except that I'm told
> that refiring the same set of cones is not a good idea,
> as they will NOT respond normally to the heatwork, and
> may result in an overfire.
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