iandol on mon 8 jan 01
Good point Jeff.
No harm done to us 'umans.
But a short circuit across one element or a bridge between two elements =
may throw the circuit breakers. In addition, any arcing which might =
occur could seriously weaken the elements as well, reducing their =
potential service life. Thinning the kanthal would increase the local =
resistance and cause a hot spot.
What do the electricians say?.
Best regards,
Ivor.
Bob Hamm on mon 8 jan 01
Jeff and Ivor,
I've been using carbide shelves in my electric kilns for more then 22 years.
I have even had elements slip out onto the shelves with no ill effect that I
could see. Have I just been lucky, or is the rationale for not using carbide
shelves in a kiln another potters myth? I'm curious as I was never told not
to use them.
Bob
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Bob Hamm
Ph (250) 765-8876 Fax (250) 765-0497
email bobhamm@look.ca web site www.bobhamm-art.com
6750 Highway 33 East
Kelowna, B.C. Canada V1P 1H9
>Good point Jeff.
>No harm done to us 'umans.
>But a short circuit across one element or a bridge between two elements may
throw the circuit breakers. In >addition, any arcing which might occur could
seriously weaken the elements as well, reducing their potential >service
life. Thinning the kanthal would increase the local resistance and cause a
hot spot.
>What do the electricians say?.
>Best regards,
>Ivor.
Edouard Bastarache on mon 8 jan 01
Allo Ivor,
I am not an electrician even if my father was
(it does not run in the family), but, I was taught
not to use silicon carbide shelves in electric
kiln because they are good electricity conductors
and there were possibilities to cause short-circuits
and ruin elements.
Later,
Edouard Bastarache
Irr=E9ductible Qu=E9becois
Sorel-Tracy
Dans / In "La Belle Province"
edouardb@sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/~edouardb/
----- Message d'origine -----
De : iandol
=C0 :
Envoy=E9 : 7 janvier, 2001 23:40
Objet : Carbide shelves in elctrric kilns
Good point Jeff.
No harm done to us 'umans.
But a short circuit across one element or a bridge between two elements m=
ay
throw the circuit breakers. In addition, any arcing which might occur cou=
ld
seriously weaken the elements as well, reducing their potential service
life. Thinning the kanthal would increase the local resistance and cause =
a
hot spot.
What do the electricians say?.
Best regards,
Ivor.
_________________________________________________________________________=
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Dennis Davis on mon 8 jan 01
Bob Hamm wrote:
> I've been using carbide shelves in my electric kilns for more then 22 years.I
> have even had elements slip out onto the shelves with no ill effect that I
> could see. Have I just been lucky, or is the rationale for not using carbide
> shelves in a kiln another potters myth? I'm curious as I was never told not
> to use them.
I too, have been using silicon carbide shelves in my electric kiln for a long time
(over 25 years) with no problems. I vaguely recall being told that silicon carbide
shelves are best used in reduction and that they would deteriorate faster in
oxidation. But they seem to be lasting just fine.
Would be interested in hearing from anyone knowledgeable about the conductivity of
silicon carbide shelves and/or deterioration in oxidizing atmosphere.
Dennis in Warrenton, VA
Bob Hamm on tue 9 jan 01
> Would be interested in hearing from anyone knowledgeable about the
conductivity of
> silicon carbide shelves and/or deterioration in oxidizing atmosphere.
>
> Dennis in Warrenton, VA
I just finished loading my electric kiln with some silicon carbide shelves,
pushing a shelf against a slipping element to hold it in the groove. It
struck me that I have been bracing elements with shelves for as long as I
can remember. And that reminded me about Dennis's question, about the
conductivity of silicon carbide shelves. So I did a little testing.
I used a clamp to fasten a wire to a freshly cleaned patch of shelf,
grinding it into the shelf to get good contact and then plugged the cord
into a wall plug. I used my multi-tester, which I had just checked in the
wall plug, to take a reading. Nothing. Not even when I tried a contact point
right beside the hot wire with the most sensitive setting. I could only get
a reading when I actually touched the hot wire.
My silicon carbide shelves do not conduct electrical current. They have not
been affected by hundreds of oxidation firings either. So unless my shelves
are a rarity, or I'm out to lunch, I think it's a myth that silicon carbide
shelves should not be used in an electric kiln. Could I be wrong?
Bob Hamm
Ph (250) 765-8876 Fax (250) 765-0497
email bobhamm@look.ca web site www.bobhamm-art.com
6750 Highway 33 East
Kelowna, B.C. Canada V1P 1H9
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