Paul Gerhold on tue 3 feb 04
As most potters who fire in electric kilns know by now a small cone in the
kiln setter fires about one cone lower than the actual firing as shown by a big
cone in the kiln. This probably accounts for some of the glaze confusion in
articles written on ceramics.
My question for our ceramic historians is why aren't the kiln setters
counterweighted so the cones work the same? In other words a cone six in the setter
would actually fire to cone six instead of 5. I have reset all my kilns to do
this so I know it is no big deal.
Paul-working like mad to get ready for the Grove.
Hendrix, Taylor J on tue 3 feb 04
Not a historian Paul, but here is my guess:
Jr cones can be used in cone packs just as their big sisters can. They
are for smaller kilns and tighter settings. They have their own
deformation chart and everything. The reason they fire "faster" than
big sis is because of the weight of the sensing rod in the kiln sitter
(I only know Dawson). That little extra weight causes the cones to bend
earlier than if they were bending under their own weight in a standard
cone position. Okay so we already knew that.
My old kiln book actually instructs me to fire several times with three
regular cones packed in the kiln to ascertain when in fact the jr does
melt. Usually it melts one cone sooner, but that is not a guarantee.
Something I understand better as well is that a kiln operator may
actually fine tune when the jr goes off by altering the jr cone setting
across the cone supports. Thicker cross section under the sensing rod =
=3D
delaying the sitter trip; thinner cross section under the sensing rod =
=3D
advancing the sitter trip. Consistent rod placement, consistent
tripping. What may be at the heart of this question is the oxidizing
and subsequent lightening of the sensing rod over time. That is a
variable.
My guess about the counter weight (some long sensing rods are counter
weighted to prevent too rapid cone deformation) is that the mechanics of
it would make it just too dicey. The sitter is not a precision endpoint
device, so a built in offset of one cone is actually a good thing.
Please start another thread about your sitter adjustment. I for one
would be very interested in hearing how you did it and how well it
operates.
Taylor, in Waco
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Paul
Gerhold
Sent: Tuesday, February 03, 2004 9:01 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Kiln setter question -ceramic historians?
As most potters who fire in electric kilns know by now a small cone in
the
kiln setter fires about one cone lower than the actual firing as shown
by a big
cone in the kiln. This probably accounts for some of the glaze confusion
in
articles written on ceramics.
My question for our ceramic historians is why aren't the kiln setters
counterweighted so the cones work the same? In other words a cone six in
the setter
would actually fire to cone six instead of 5. I have reset all my kilns
to do
this so I know it is no big deal.
...
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