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betr: re: indication of temperature

updated sat 4 jan 03

 

Waltraud Koestler on fri 3 jan 03


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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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