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firing time

updated wed 28 may 03

 

mel jacobson on mon 10 may 99

thanks and congrats tony......i am ripping the hard brick out of the drive
as i write.

speed is based on the kind of clay, glaze, technique that you are firing.
the salt kiln at the farm \ 35 cu ft...fires in 4.5 hours....cone 11.
so, we do it in that time.....salt is not so fussy. we can fire every day
for 6 days straight. good quality potters in camp/know what they are doing.

i would not fire celedons, temmokus, etc fast..........like to give them
time to mature. slow cool, like reds. even re/lite the kiln, warm
on the way down.

i fire in about 9 hours......but, then, hell, what else is there to do.
why rush?

but, i sure agree with tony.....know your kiln, it's limits, speed and
potential.
when you need to fire fast, rush around........have the power to do so.
if you are not in a hurry.......take your time.

no, question........clay is being fired in 30 minutes to cone 6-9 in
industry. they move right along.

ron roy has repeated to us all, often.......bisque slow...maybe 15-20 hours.
cost the same.
and get the junk out of your clay body.

there is no one answer to firing speed. tony's kiln, david hendley, they fire
with wood......get after it. but they can fire just like gas.......do it
in 6 hours.
obviously, if you want `real` ash affects, slow down.......30-50 hours....cone
14.
no simple answer.
but, if you know your kiln, can change the settings for speed.....when
you need it....well, that is really nice.
big time weather change can really make you want to speed up.
get the thing done.......but, i really hate to ruin an entire kiln, just
because i may miss the start of a movie......nothing should ever
interfere with the conclusion of a firing. ever. except nature. (well, and
going to walmart to get shoe laces.)

boy, john britt went after leech, now nils...he is a brave man.
it takes a heap of courage to do what john did, and believes...
and he put the` cheese on the line`......i want to say that i
stand with john. there has been a great deal of fantasy written
about leech and hamada......much by themselves.
thank you john, you are fine man.
(nils will fry your cookies however.)
mel/mn





http://www.pclink.com/melpots

vida vidute on wed 21 may 03


I had problem with the glaze it kept crazing. So I called the company, where I get clay and glazes, they said I fire it too fast. I have Duncan kiln, I am using cone 6 right know. How should I pick the temp. They say it takes about 12 hours. How do I have to pic up temp. ? I am sorry it sounds primitive, but I don't know how else to explain. Do I pick up every 4 hours, low, after four hours mid, after four hours high fire?
Or slowlier at the begining then faster at the end? Does somebody know what periods the temp has to be picked up?



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Snail Scott on wed 21 may 03


At 08:51 AM 5/21/03 -0700, you wrote:
>I had problem with the glaze it kept crazing. So I called the company,
where I get clay and glazes, they said I fire it too fast. I have Duncan
kiln, I am using cone 6...



That's not it. They are simply wrong. There is NO
commercially-made home-studio electric kiln that
can fire too fast for decent vitrification and
glaze/body interface. They just can't go that fast,
even if you wanted them to. The fact is, some
glazes simply don't fit some clays. NO glaze will
fit every clay. If you really like the glaze, change
clays 'til you find one that it fits better. Or
try other glazes 'til you find one that fits your
clay.

If you really want to try firing slower, though,
don't bother spending more time on 'low' & 'med';
that's just a waste. Turn to 'medium' at your
normal time (1 hour or so?), then on to 'high'
at the normal time, too. Use witness cones,
(but you do anyway, right?) and when you get to
^4 or so, turn the middle ring back to 'medium'.
It'll slow down a LOT. Keep it there for a few
hours. Depending on how good your elements are,
and how well insulated your kiln is, it may
creep up to ^6 eventually, or not. If it doesn't
then turn the middle ring back to 'high' after a
few hours and finish it.

I can pretty much predict that it won't help
your crazing much. It may make your glaze look
more interesting, though. So will leaving it on
'low' for a few hours after the cone bends, to
slow the cooling rate.

-Snail

Arnold Howard on wed 21 may 03


The fastest kiln I have ever fired is the Paragon QuikFire. It reaches
1000F in five minutes. It fires so fast that it bloats witness cones. I
have over-fired it just answering the phone.

Sincerely,

Arnold Howard
Paragon Industries, L.P.
www.paragonweb.com


From: Snail Scott
There is NO
> commercially-made home-studio electric kiln that
> can fire too fast for decent vitrification and
> glaze/body interface. They just can't go that fast,
> even if you wanted them to.

Mary White on wed 21 may 03


Vida--

My Duncan kiln has a plate on the side with the firing instructions
printed right on it. They work. It's a DK 820X-2. I also have a
Duncan manual with instructions for other models. Let me know what
kind yours is and I'll see if I can find anything on it.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Mary
on the wet west coast of British Columbia
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



>I had problem with the glaze it kept crazing. So I called the
>company, where I get clay and glazes, they said I fire it too fast.
>I have Duncan kiln, I am using cone 6 right know. How should I pick
>the temp. They say it takes about 12 hours. How do I have to pic up
>temp. ? I am sorry it sounds primitive, but I don't know how else to
>explain. Do I pick up every 4 hours, low, after four hours mid,
>after four hours high fire?
>Or slowlier at the begining then faster at the end? Does somebody
>know what periods the temp has to be picked up?
>
>

Ron Roy on tue 27 may 03


The key question here is just how fast do you fire to cone 6 and are you
using cones?

It is most likely that there is enough difference in the expansion of the
clay and the glaze to cause crazing under any circumstances - you will find
that out by trying a slower firing. It is true that some fit problems are
because of fast firing - the glaze does not get enough chance to bond
properly with the clay. Most of these situations appear when the glaze
winds up to BIG for the clay - we call this shivering - the opposite of
crazing.

We are interested in finding out if you are firing fast and if that is the
cause of the crazing- then we can have some insight into the technical
support you are getting from your supplier.

RR


>At 08:51 AM 5/21/03 -0700, you wrote:
>>I had problem with the glaze it kept crazing. So I called the company,
>where I get clay and glazes, they said I fire it too fast. I have Duncan
>kiln, I am using cone 6...

Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513