Wilkinson on sun 3 may 98
There is much more to the subject of cones and temps than the questions I
am going to ask I know. But often times some one will say "fire to cone
thus and such." When someone refers to say cone 6, which cone are they
referring to the witness cone, small or large cone? Also it would be
interesting to know what is the accepted temperature for each cone.
According to my chart they vary from small to large. The later info would
be good to have in the event one has to use just a pyrometer some day. Any
thoughts or suggestions? TIA
Lori Wilkinson
BobWicks on mon 4 may 98
Lori:
Good question! I have often wondered why clay art people do no specify which
cone they are referring to as there is a big difference between a small ^6 and
a large ^6. The rate per hour of temperature seems to be the governing
factor.
Bob
Stephen Mills on tue 5 may 98
Just to put one rather important fact in perspective: Pyrometers measure
temperature only. Cones measure accumalated heatwork... think of that in
terms of suntan. Yeah that's ultra-violet I know but the principle is
much the same: 10 minutes out in the sun will get you a lightish tan
(I'm talking UK sunshine!), 20 minutes a darker tan, etc.etc.etc. No
difference in temperature, just the time spent in it, that's accumilated
heatwork. SO.... what you measure with a pyro. ain't the same as what
you measure with cones.
We've recently done a firing in a small wood kiln with a too small
firebox (my mistake), never got above 900oC on the pyrometer, BUT... 6
hours of that got cone 6 nicely over and cone 8 starting.
Steve
Bath
UK
In message , Wilkinson writes
>----------------------------Original message----------------------------
>There is much more to the subject of cones and temps than the questions I
>am going to ask I know. But often times some one will say "fire to cone
>thus and such." When someone refers to say cone 6, which cone are they
>referring to the witness cone, small or large cone? Also it would be
>interesting to know what is the accepted temperature for each cone.
>According to my chart they vary from small to large. The later info would
>be good to have in the event one has to use just a pyrometer some day. Any
>thoughts or suggestions? TIA
>
>Lori Wilkinson
>
--
Steve Mills
Bath
UK
home e-mail: stevemills@mudslinger.demon.co.uk
work e-mail: stevemills@bathpotters.demon.co.uk
own website: http://www.mudslinger.demon.co.uk
BPS website: http://www.bathpotters.demon.co.uk
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