Elizabeth Priddy on thu 12 oct 06
Half full is ok, but you will do better to space the
work out evenly throughout the kiln, not half loaded
and then fired with the top half just empty space.
I think the sensors in the kiln, both for a kiln
setter type an the thermocouples would not read
correctly if the bottom of the kiln is loaded tgiht
and the top was empty.
E
Elizabeth Priddy
Beaufort, NC - USA
http://www.elizabethpriddy.com
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Don Goodrich on thu 12 oct 06
Hi Cindy,
The more you have in the kiln, the slower it'll cool.
If your glazes are touchy about timing, it could make a difference
how big your kiln load is, especially if you have more or fewer
shelves in there to soak up and retain the heat. An extreme example
of this is the difference between firing a small test kiln and
firing a larger electric. Same temperature, but way faster in
the test kiln. The colors of some glazes turn out different because
of it. A less exteme example: If I fire the larger kiln with a few
items glazed in Floating Blue and maybe one shelf, I get a darker
color. The same kiln with as many pieces as it will hold with three
shelves cools slower and the blue is much lighter, sorta cloudy.
The short answer is maybe. It depends. If a range of effects is
acceptable and you can't afford to wait, go ahead.
Good luck finding out.
Don Goodrich
Cindy Reed on thu 12 oct 06
I have searched through the archives and could not find an answer to my
query so am looking for help from the experts on this forum.
We have electric kilns that are fired to cone 6. I know it makes sense to
fire a fully loaded kiln for economical reasons...are there other reasons
that you would not want to fire a kiln that is less than half full that have
to do with the glaze not firing properly? Or any other negatives regarding
a half or less than full kiln.
Thank you for your help,
Cindy Reed
Greenville, NC
Mayssan Shora Farra on fri 13 oct 06
On Thu, 12 Oct 2006 21:44:46 -0400, Cindy Reed wrote:
..are there other reasons
>that you would not want to fire a kiln that is less than half full that
have
>to do with the glaze not firing properly? Or any other negatives
regarding
>a half or less than full kiln.
Dear Cindy:
When in a rush for a few things, I have fired my kiln half full or even
less to no ill effect, but my glaze is not finicky as I use mostly stains
under a clear glaze that does not need slow cooling, but even for a glaze
that requires slow cooling it would not be an issue in a computerized
kiln, and even in manual you can watch closely and soak the glaze manually.
I hope that helps some.
Mayssan, in bbrrrr is it winter already? Charleston WV.
http://www.clayvillepottery.com
L. P. Skeen on fri 13 oct 06
Cindy, the only thing I can think of is the way electric kilns are =
designed to work in the first place. Unfortunately, I cannot think of =
the "official" term for it, although I want to call it radiant heat, but =
the idea is that heat comes first from the kiln elements and heats =
whatever is closest to them (the ware on the outer edges of shelves, =
shelf edges and posts). These objects in turn help heat the objects =
closer to the center of the kiln. I'm not a kiln expert (nor do I play =
one on TV), but it seems to me that if your kiln is less than half full, =
it might actually take more energy to fire it because there are fewer =
objects to help conduct the heat around.
L. P. Skeen, Summerfield NC
Get your 2007 Clay Lover's Calendar at =
http://www.living-tree.net/calendar.htm
----- Original Message -----=20
From: Cindy Reed=20
We have electric kilns that are fired to cone 6. I know it makes =
sense to fire a fully loaded kiln for economical reasons...are there =
other reasons that you would not want to fire a kiln that is less than =
half full that have
to do with the glaze not firing properly?
Mert & Holly Kilpatrick on fri 13 oct 06
Cindy,
We have found that certain glazes are quite sensitive to speed of firing,
and a partially filled kiln will not only fire faster, it will also cool
faster, and for some glazes that can make quite a difference. When we don't
want that to happen, but through poor planning :-) we need to fire a less
than full load, we will put some posts in just to add some mass, so that we
can maintain some consistency. Some glazes you will find it doesn't matter.
Holly
East Bangor, PA
>We have electric kilns that are fired to cone 6. I know it
>makes sense to fire a fully loaded kiln for economical
>reasons...are there other reasons that you would not want to
>fire a kiln that is less than half full that have to do with
>the glaze not firing properly? Or any other negatives
>regarding a half or less than full kiln.
>
>Thank you for your help,
>Cindy Reed
>Greenville, NC
Nancy Braches on fri 13 oct 06
Cindy
I'm sure someone has said this but my understanding is it is better "economically" to fire a full load because of the heat distribution being held in the pottery and throughout the kiln.
I have fired half a load due to an emergency order, takes a little more electric, fired fine though. I made sure to distribute the pieces even through the kiln to help with even distribution.
Do you have a ring you can remove from the kiln and fire it smaller?
Nancy
Cindy Reed wrote: I have searched through the archives and could not find an answer to my
query so am looking for help from the experts on this forum.
We have electric kilns that are fired to cone 6. I know it makes sense to
fire a fully loaded kiln for economical reasons...are there other reasons
that you would not want to fire a kiln that is less than half full that have
to do with the glaze not firing properly? Or any other negatives regarding
a half or less than full kiln.
Thank you for your help,
Cindy Reed
Greenville, NC
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Nancy
Hilltop Pottery
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Snail Scott on fri 13 oct 06
On Oct 12, 2006, at 11:46 PM, L. P. Skeen wrote:
> ...heat comes first from the kiln elements and heats whatever is
> closest to them (the ware on the outer edges of shelves, shelf edges
> and posts). These objects in turn help heat the objects closer to the
> center of the kiln...it might actually take more energy to fire it
> because there are fewer objects to help conduct the heat around...
Not quite the way it works. If there are fewer objects
between the radiant-heat source and the thing in
question, that thing just gets heated directly. While
intervening objects do re-radiate heat, that only
happens after they've already absorbed heat,
some of which they 'keep'.
Sort of like passing a snack tray around a party -
if there are a lot of people there, each will take
a canape before passing the tray on. If there are
fewer people there, the tray will get from the host
to you a lot quicker, and with more food still on it.
(That's a heating analogy. For a cooling analogy,
well, think about a shorter line at the bathroom
door.) ;)
When loading a partial load in a kiln, keep
the work openly spaced, not bunched up tightly,
so that everything will heat evenly. (Since the
firing will likely be faster than usual, there will
be less time for heat to equalize.) Try to keep
the clay grouped near the thermocouple or kiln
sitter or witness-cone pack, though, so that the
heat readings you get will be accurate for that
location. If your thermocouple is near the top,
for example, don't have all the work (or any of it)
near the bottom. This is especially true for fuel
kilns, since airflow will be strongly affected by
the density of the load. For a fuel kiln, it may
be a good idea to load all the usual furniture,
even empty, just to help maintain the usual
airflow pattern. Placement is less critical for
electric kilns, but why not shoot for maximum
accuracy and place the work somewhere
near your heat indicator of choice?
Glazes requiring a slow firing, soak, or slow
cooling may require compensation in your
firing schedule, as others have noted. Other
glazes may require no adjustments.
-Snail
Arnold Howard on fri 13 oct 06
From: "Cindy Reed"
I know it makes sense to
> fire a fully loaded kiln for economical reasons...are
> there other reasons
> that you would not want to fire a kiln that is less than
> half full that have
> to do with the glaze not firing properly?
As already stated in the answers you've received, distribute
the ware evenly throughout a lightly loaded kiln. If you are
firing a tall piece or for some other reason you cannot
distribute the load evenly, then fire the kiln slowly.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
Lauren Bellero on sat 14 oct 06
cindy reed wrote:
> ... are there other reasons that you would not want to
>fire a kiln that is less than half full
hi cindy,
no need to fire a less than half full electric kiln.
there are times where you just gotta have that
work fired 'now' -- max kiln capacity or not!
in that case, fill in spaces with kiln furniture
or scrap pots. the kiln doesn't know the
difference!
all the best,
lauren
--
Lauren Bellero, Mudslingers Pottery
http://mudslingerspottery.net
Red Bank, NJ
Cindy Reed on sun 15 oct 06
Thank you for them many responses to my query. I am glad you are all here
and willing to impart your knowledge to others.
Thanks again for your time,
Cindy
On 10/14/06 12:54 PM, "Lauren Bellero" wrote:
> cindy reed wrote:
>> ... are there other reasons that you would not want to
>> fire a kiln that is less than half full
>
> hi cindy,
> no need to fire a less than half full electric kiln.
> there are times where you just gotta have that
> work fired 'now' -- max kiln capacity or not!
> in that case, fill in spaces with kiln furniture
> or scrap pots. the kiln doesn't know the
> difference!
>
> all the best,
> lauren
>
> --
> Lauren Bellero, Mudslingers Pottery
> http://mudslingerspottery.net
> Red Bank, NJ
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
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