Stephen Mills on tue 14 mar 06
From this side of the pond it's interesting reading the many posts on
the subject of thermocouples.
I'm heartened to read Arnold's recommendation of Type S T'couples;
Type K have held sway for far too long in my opinion, working at
temperatures they were never designed for. They are accurate up to about
1150 Centigrade (2102 F), after that they get increasingly inaccurate
and they have a VERY short accurate life span. S is accurate to 1700 C
(3092 F), very long lived, but the probe is frail, especially when
wacked by a pot or a shelf, and they are comparatively expensive!
Here in the UK and I think in Australia there is a gradually increasing
move towards Type N for fuel burning kilns. These are widely used in
industry, so they are not rarities; over here there are at least two
companies (probably more I haven't heard of yet) making them and they
are a lot cheaper than Type S. They have other advantages too - they max
out at 1300 C (2372 F) have an inconel steel sheath so don't break and
have a much longer life span than type K (though not as long as Type S).
However if you are thinking of one for an electric Kiln don't, unless
you can put it inside an old ceramic sheath; the metal probe is NOT to
be used near electric elements unless protected.
I recommend a hunt for Type N - I use 2 in a Wood-Salt Kiln.
Steve
Bath
UK
In message , Arnold Howard writes
>The S-Type thermocouple lasts indefinitely
>and is well worth the extra cost. When they
>fail, it is ordinarily only because a shelf
>bumped into the thermocouple during loading.
>
>I'm not sure APM elements yield a lower cost
>of element per firing. Though they last a lot
>longer, they also cost more. Their main
>advantage is that they save you the labor in
>changing elements.
>
>Sincerely,
>
>Arnold Howard
>Paragon Industries, L.P., Mesquite, Texas USA
>ahoward@paragonweb.com / www.paragonweb.com
>
--
Steve Mills
Bath
UK
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