centa uhalde on tue 23 jun 98
Hi Clayart mentors,
I bought this Cress Firemate kiln used with pyrometer, also used. It seems
to rise and fall all right but how do I know it is an accurate reading of
the temp? I know it's not all temp I'm after but somehow it seems off to me
at times?
Centa
David Woodin Set Clayart Digest on wed 24 jun 98
Is it analog or digital, is the thermocouple enclosed in a protecting tube, if
not does the exposed wire seem burned, flaking, greenish in color, or wire
size different at the exposed end versus where the extension wire is
connected? The only way to calibrate a pyrometer is with a calibrator which
is not likely done outside of an industrail enviroment. Digital pyrometers
are very accurate, analog are accurate only if the load in resistance is the
same as the nameplate says the instrument is calibrated for. The big
inaccuracy is the thermocouple plus extension wire, type K can be + or minus
13 deg F and still be within allowable spec.s., which still is only about 1/2
a cone at cone 10. The other big problem is cone tables which are for 108 deg
F per hr and if your kiln doesn't go at that rate then you will think the
pyrometer is not reading correctly. Once you establish the temperature at
which the cones fall then you can easily repeat your firing by looking at the
temperature. But always use witness cones.
Cindy on fri 26 jun 98
Centa,
Using witness cones may give you some idea of the accuracy of your
pyrometer. This is sketchy, of course, as the cones measure heat work,
while the pyrometer measures actual temperature. In the end, it's the cones
that really matter, of course. The actual temperature can give you an idea
of what's happening in the kiln, but the heat work is the important thing.
Cindy Strnad
Earthen Vessels
Custer, SD
USA http://blackhills-info.com/a/cindys/menu.htm
Karin on fri 11 nov 05
Someone once told me that the only pyrometer to get was a digital, any =
suggestion what brand, please share your experience.
Thanks,
Karin Hurt
www.laughingbearpottery.com
Louis Katz on mon 14 nov 05
Depends what you are looking for. If you really only need rough numbers
and a sense when a kiln is going up or down, the analog meters are fine
and do not require batteries. Either way locating the meter away from
heat in a protected location over the long term is more important than
meter type. They all die if they get too hot or kicked too hard.
Longest living meter that still works good that I know of is a real
high quality analog meter about the size of shoe box at the Archie
Bray. Its been in use since before 1977 when I first visited. Type R.
Probably cost an arm and a leg originally but I am sure it came out of
the brickyard. Might have been there when Peter Voulkos and Rudi Autio
were there. Easy to read too. I had an early digital pyrometer,
eventually the display died. It stayed calibrated to within 5 or ten
degrees for about 5 years then drifted a bit (with a new thermocouple
when needed).
I would if I were in the market invest in a type r meter/thermocouple
or other platinum platinum / rhodium thermocouple if I were firing
about 1850 F. To me this is a more important factor than analog or
digital.
Louis
***Louisiana Mississippi Ceramics and Potters Information page*****
http://falcon.tamucc.edu/wiki/Katz/LAMIPotters
On Nov 11, 2005, at 11:36 AM, Karin wrote:
> Someone once told me that the only pyrometer to get was a digital, any
> suggestion what brand, please share your experience.
>
> Thanks,
> Karin Hurt
> www.laughingbearpottery.com
>
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Hank Murrow on mon 14 nov 05
On Nov 11, 2005, at 9:36 AM, Karin wrote:
> Someone once told me that the only pyrometer to get was a digital, any
> suggestion what brand, please share your experience.
Dear Karen;
Not so. The type of thermocouple(the part that goes in the kiln) is far
more important. The cheap ones are type K, and are pretty useless above
cone 2 or so no matter what kind of readout device you use. The Type S
thermocouple is around 6 or 7 times as expensive, and work accurately
beyond Cone 10, no matter what device reads them, digital or analog. If
you fire above cone 3, the best kind has a type S thermocouple, and can
be read out accurately with a good meter or digitally.
The OxyProbe has a Type S thermocouple and is read digitally, and has
an oxygen sensor built in to read the atmosphere.
Cheers, Hank
www.murrow.biz/hank
Deborah Thuman on thu 1 jul 10
The last firing I did, I didn't see the cones clearly and stopped the
reduction too soon. While I got some interesting results, they weren't
the results I wanted.
I'm thinking that a pyrometer could help me avoid that problem. I'm
using Jim's fancy goggles that protect my eyes from the heat and
light, plus they do allow me to see the cones more clearly. But.....
I'm obviously not doing a good enough job.
So.... Would sticking the pyrometer in the peep every so often give me
an additional gauge for temp and help me avoid stopping reduction too
soon? I'm using the university's kiln so drilling a hole in the side
of the kiln for a pyrometer is not an option. I'm not so sure I want
to leave a pyrometer stuck in a peep all during reduction.
Thanks in advance.
Deb Thuman
http://debthumansblog.blogspot.com/
http://www.etsy.com/shop.php?user_id=3D5888059
http://www.facebook.com/pages/Deb-Thumans-Art-Page/167529715986
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