Waltraud Koestler on fri 3 jan 03
free email, free, branded, web based, free web based email, communicatio=
ns, internet, software, advertising banners, e-mail, free software'>ad>Hel=
lo Earl,
in one of my books is first described a "Nenntemperatur" and =
additionally the falling temperature of the cones.
This is why I'm so confused.
The Nenntemperatur is 1230 C and the falling temperature 1260 C
(heating rate 150 C per hour).
I set 1230 C on my controller with 150 C per hour to 550 C and than >
full speed until 1230 C with half an hour souking.
When I use this schedule, the cone 7 Seger is falling. Seger cone 7 >
falls at 1260 C.
Your information tells me, that the indication on the Clay bags is
=
the falling temperature and not the "Nenntemperatur".
Sorry, I cant't translate Nenntemperatur in englisch!
May be there is someone at the list who can translate that?!
I tried to add a copy of the page with an overviev, but it was
rejected by the server.
Thank you very much!
Waltraud
http://www.p=
lanet-b.net - Das Internetportal f=FCr Bertelsmann-Mitarbeiter und Ihre =
Familien.
Snail Scott on fri 3 jan 03
At 12:39 PM 1/3/03 +0100, Waltraud wrote:=20
I set 1230 C on my controller with 150 C per hour to 550 C and than=20
full speed until 1230 C with half an hour souking.
When I use this schedule, the cone 7 Seger is falling. Seger cone 7=20
falls at 1260 C.
<<<<<<<<
The difference is the soaking! You reached 1230=BAC, then=20
soaked, so the heat-work was greater than it would have=20
been had it reached 1230 and begun cooling immediately.=20
The pyrometer in the kiln only reads temperature, so it=20
would have read the same even if you'd soaked it for 24=20
hours! The cones know the difference, though. More time=20
can be equivalent to more temperature in its effects on=20
both clay and cones. It's not that a Seger ^7 falls at=20
1260=BAC, but that it falls at 1260 at a certain amount of=20
firing time. For a shorter firing, it would have needed=20
a higher temperature to fall. Since you added the soak,=20
making your firing longer, it fell at a lower temperature.
When a chart says that a cone falls at a particular=20
temperature, that's just an oversimplification for the=20
sake of convenience. It is NOT how cones actually work.
-Snail
>>>>
http://www.planet-b.net - Das Internetportal f=FCr Bertelsmann-Mitarbeiter
und Ihre Familien.=20
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