Fred Parker on wed 6 dec 06
Based on a cursory archive search I conclude saggar firings in electric
kilns are not good. Is this so, or is there a way to achieve reduction in
an electric kiln without damaging elements?
Many thanks,
Fred Parker
Arnold Howard on wed 6 dec 06
From: "Fred Parker"
> Based on a cursory archive search I conclude saggar
> firings in electric
> kilns are not good.
I can't speak from experience about saggar firing. But I can
quote from a letter that Paragon received in 1977:
"Five years ago I purchased a Paragon model H-17HS kiln. I
fire to cone 9. I do all my bisque firing in the same kiln.
I reduce in this same kiln. I have used this kiln
continually since November of 1972. I have not replaced the
elements or had any trouble of any kind!
"I place a sagger in the kiln with the pots in the sagger.
Then I place charcoal briquettes around the pots. The
reduction is surprisingly heavy."--Don Hanson
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
Marcia Selsor on wed 6 dec 06
Fred,
You need to protect your elements from the carbon of the
combustibles. ITC for metal would do that OR control the combustibles.
Ask the expert, Russel. He only does saggar firings in an electric in
his studio in Brussels.
He uses heavy foil to seal the combustibles. Russel, please explain.
Marcia Selsor
http://marciaselsor.com
On Dec 6, 2006, at 8:05 AM, Fred Parker wrote:
> Based on a cursory archive search I conclude saggar firings in
> electric
> kilns are not good. Is this so, or is there a way to achieve
> reduction in
> an electric kiln without damaging elements?
>
> Many thanks,
>
> Fred Parker
Ann Brink on wed 6 dec 06
And here I thought saggar firings were the only way to get reduction in an
electric kiln without damaging elements. I've only done it a few times, but
the saggar was pretty tight and I thought it was ok to do so.
Ann Brink in Lompoc CA
(mostly about pottery)
Subject: Saggar firing in Electric Kiln
> Based on a cursory archive search I conclude saggar firings in electric
> kilns are not good. Is this so, or is there a way to achieve reduction in
> an electric kiln without damaging elements?
>
> Many thanks,
>
> Fred Parker
>
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Fred Parker on thu 7 dec 06
Arnold Howard:
This is very interesting. I have heard all kinds of stories abt whether
or not one can reduce in an electric kiln without adverse consequences.
In general, do you believe it will damage elements?
Thanks,
Fred Parker
On Wed, 6 Dec 2006 09:08:12 -0600, Arnold Howard
wrote:
>From: "Fred Parker"
>> Based on a cursory archive search I conclude saggar
>> firings in electric
>> kilns are not good.
>
>I can't speak from experience about saggar firing. But I can
>quote from a letter that Paragon received in 1977:
>
>"Five years ago I purchased a Paragon model H-17HS kiln. I
>fire to cone 9. I do all my bisque firing in the same kiln.
>I reduce in this same kiln. I have used this kiln
>continually since November of 1972. I have not replaced the
>elements or had any trouble of any kind!
>
>"I place a sagger in the kiln with the pots in the sagger.
>Then I place charcoal briquettes around the pots. The
>reduction is surprisingly heavy."--Don Hanson
>
>Sincerely,
>
>Arnold Howard
>Paragon Industries, L.P., Mesquite, Texas USA
>
Lauren Bellero on thu 7 dec 06
Fred Parker wrote:
>Based on a cursory archive search I conclude saggar firings in electric
>kilns are not good. Is this so, or is there a way to achieve reduction in
>an electric kiln without damaging elements?
hi fred,
i've successfully saggared in my electric kiln.
i was first inspired by an article by david ogle
in clay times a few years ago, and corresponded
with him for some insight. he was very giving and
helpful.
basically, i use a 12"x12"x 2' terra cotta flu liner with kiln shelves
as the top and bottom of the the saggar, "sealed" with
a coil of clay. i tumble stack the pots (bisqued) with my
usual ingredients for a pit fire: copper, iron, rock salt, straw and
a bit of sawdust, candle for a loooong time to dry out
the coils and the liner, and fire to 010. fyi: my kiln is itc'd
which i don't think is an absolute must, unless your using salt
which i like to do.
you can see some of the results on my site (below). click
on gallery and then saggar fired.
all the best!
lauren
--
Lauren Bellero, Mudslingers Pottery
http://mudslingerspottery.net
Red Bank, NJ
Snail Scott on fri 8 dec 06
>On Wed, 6 Dec 2006 09:08:12 -0600, Arnold H quoted a letter:
>>I reduce in this same kiln. I place a sagger in the kiln
>>with the pots in the sagger.
>>Then I place charcoal briquettes around the pots.
At 08:30 AM 12/7/2006 -0500, Fred P wrote:
>This is very interesting. I have heard all kinds of stories abt whether
>or not one can reduce in an electric kiln without adverse consequences.
>In general, do you believe it will damage elements?
There seems to be some confusion about
what is meant by 'reducing in an electic
kiln'.
Arnold's story and similar ones about saggar
firing, as well as those discussing ITC
element coatings and the other successful
'electric reduction' stories, all have a
common aspect:
The elements were PROTECTED from the
reducing atmosphere, i.e. NOT in contact
with the reducing atmosphere itself.
So, it's not so much a matter of "Will
reducing in an electric kiln cause element
damage?" It is a question of 'Are the
elements in contact with a reducing
atmosphere?" If they are, then yes, the
reduction will eat up the oxide layer that
protects the elements and shorten their
life. If not in contact, then no, the
atmosphere surrounding the elements is
still an oxidizing one, and their lifespan
will be normal.
-Snail
Russel Fouts on fri 8 dec 06
>> Based on a cursory archive search I conclude saggar firings in
electric kilns are not good. Is this so, or is there a way to
achieve reduction in an electric kiln without damaging elements? <<
It depends:
I smoke fire in my electric kiln by tightly wrapping the pots and
some newspaper as the combustible in aluminium foil as a saggar.
Very little smoke gets out of the 'saggar' but I'm not, generally,
using more than a small amount of newspaper.
My kiln is also very well vented with an orton envirovent.
I bought my kiln in 96 and have not replaced the elements yet.
This method works really well for me, see my work at http://www.mypots.com.
One thing though, the foil starts to break up around 650 centigrade
so you really can't use any colorants because they don't do anything
at that low a temperature (I fire around 500c). 'Salts' might work
but I've never tried them.
HOWEVER, if you are willing to factor into the cost of doing your
work, replacing your elements more often, you can do anything you want.
I have friend in NC who does 'pit' firings in her electric kiln using
all kinds of combustibles, salts, colorants, etc wrapped in aluminium
foil saggars in her electric kiln.
She has a good vent too.
After the firing, her kiln is a real mess. Everything that was once
in a saggar is now all over the shelves. It's a big cleanup job. But
she's willing to accept this and replacing her elements more often in
order to work this way.
So, it's all a matter of what you're willing to accept.
The vent is really important to protect YOU, or put your kiln outside.
Russel
Russel Fouts
Mes Potes & Mes Pots
Brussels, Belgium
Tel: +32 2 223 02 75
Mobile: +32 476 55 38 75
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Ivor and Olive Lewis on fri 8 dec 06
Dear Fred Parker,=20
You ask about Saggar Firing in an Electric Kiln and the deterioration of =
Kiln Elements.
I would like to know what evidence proves kiln elements deteriorate when =
firing Saggars. Has it been shown that the tenacious oxide that develops =
on the metal is reduced by Carbon Monoxide ? If you check some chemistry =
books about metal extraction there is usually a list of metals showing =
how readily they are separated from their oxides by direct reduction =
with Carbon monoxide. Metals like Copper, Lead, and Tin are, while =
others such as Aluminium, Molybdenum, Chromium, Cobalt and Titanium are =
not. A lot will depend on the metallurgy of the elements in question =
which power the kiln you intend using.
That being said, given that a Saggar is a container that is supposed to =
isolate the goodies inside form the outside where is the problem.
If the seal is less that perfect and stuff generates voluminous clouds =
of smoke or is volatile and the gas is flammable there should be nothing =
to worry about provided the kiln is well ventilated.
So, what are the arguments against firing saggars in an Electric kiln =
and do they stand up to scrutiny ?.
Is it true that deterioration of some kiln element materials happens =
because of grain boundary diffusion of oxygen that reduces the mass of =
metal and increases the resistance to electrical flow causing =
overheating and burnout ?
Best regards,
Ivor Lewis.
Redhill,
South Australia.
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