Janet H Walker on sun 29 sep 96
I'm soliciting recommendations on your favorite text/reference books on
firing electric kilns. Particularly small ones. I'm having problems
with understanding how to pack it for even firing and for reasonably
accurate pyrometer readings. (e.g. it seems as if putting the shelf
just an inch above where the pyrometer sticks in gives falsely high
readings and the kiln can get underfired. How far above or below
should one place the shelves from the various sensors (sitter, pyro?)
On the latest firing, I got a two cone difference between top and
bottom. This is WITH an envirovent. I had the bottom fairly well
packed with 10" pieces. The very top shelf had ~5" height and was
lightly packed. It never got near cone 6. On the bottom, both
6 & 7 had gone down.
Furthermore, they both went down at the same time. Is it possible
to have a bad batch of cones? They have 6 stamped on them alright
(all my cones are the colored kind.)
Anyhow, perhaps you sense the kind of expert treatise I am looking for.
Thanks in advance.
Jan Walker
Fun & Functional Arts
Cambridge, MA USA
Tamsin A. Whitehead on mon 30 sep 96
On Sun, 29 Sep 1996, Janet H Walker wrote:
> ----------------------------Original message----------------------------
> readings and the kiln can get underfired. How far above or below
> should one place the shelves from the various sensors (sitter, pyro?)
>
> On the latest firing, I got a two cone difference between top and
> bottom. This is WITH an envirovent. I had the bottom fairly well
> packed with 10" pieces. The very top shelf had ~5" height and was
> lightly packed. It never got near cone 6. On the bottom, both
> 6 & 7 had gone down.
>
> Furthermore, they both went down at the same time. Is it possible
Sorry no advice to give - just wanted to add my similar problems to the
list and add my cry for advice!
I have a very old Amaco front loading kiln, I think one of the "Fine Art"
types. It is very small - about one and a half cubic feet. I am getting a
difference of between 2 and three cones between top and bottom. I try to
fire to about ^6 (!). I don't have a controller, so fire to what I see is
happening to the cones in front of the peephole which is situated half
way up the kiln.. I
generally fire to a ^5 to get an "average" of ^6 but often what happens
is that I get ^5 at front of top shelf with temperatures increasing to ^8
at the back of the bottom shelf. With it being such a small kiln, I try
to maximise space and keep the bottom shelf fairly low - about 1" above
the elements. This may be trapping a great deal of heat, and in my next
firing I am going to try two broken halves of shelf with a space between
them to see if this helps to circulate the heat a little better.
Like Michelle Lowe noted in her post about firing problems, I too have
gaps around the door frame where you can see the red glow ( and where
some venting happens (!), but I too have tried blocking everything with
fiber and it didn't make any difference to the firing. I have also tried
stacking/loading in different ways and densities, but to no avail..
This is my first kiln and I have to say I am learning a lot!!!!!
I have mentioned (loudly!) this problem to various clay friends and gurus
and the general opinion is GET A NEW KILN AND STOP WASTING TIME!
But I don't have the $$$$ right now so if anyone has any advice to give I
too would be very grateful!
Tamsin
Nottingham, NH
Jeff Lawrence on tue 1 oct 96
Both my Olympic and my Aim electric had some cold zones and they got back on
track with new elements. I just put a new element in my little Olympic test
kiln, and voila! ^04 in 3 hours instead of 6-7.
Putting new elements in is tedious but easy. I invite you to profit by my
mistakes and heed the following:
1) Replace one element completely before you start the next, to make sure
you get the connections right
2) Unplug the kiln before doing anything.
Try Euclids Elements - 800-296=5456. They're knowledgeable, helpful, and
have sent all my orders within a day or two. They didn't laugh at me because
I didn't know top and middle elements are different temperatures.
Jeff Lawrence
jml@sundagger.com
505-753-5913 vox/fax
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