Cliff Glover on mon 21 dec 98
I would like to hear from anyone who has had their gas kiln explode
during a firing.
Earl Brunner on tue 22 dec 98
Cliff, your post brought such funny/not so funny images to mind! For
instance, I wanted to know why you might be asking? Have you had recent
experience in this area? I'm sure that there are many stories of
"accidents". I would guess that most of them came from errors in the burner
lighting process. I used to have a propane fired, down draft that had a
stacked brick door that I once blew off (on top of myself). I had forgotten
to close the valves on all the burners before turning on the gas and it
built up inside before I got the flame to the burners. Never did that
again. Broke a lot of those nice soft brick in the door! (They weren't so
soft either) Once lit and firing I can't think of circumstances that would
cause an explosion, without some kind of fuel delivery interruption. Most
commercially manufactured kilns would have to have safety equipment
installed in order to fire. As a side note, I just fired my Geil kiln out
in the back yard Saturday to cone ten and we had a wind storm during the
firing that had gusts to 50 miles per hour. I was well committed into the
firing when the wind kicked up and on a deadline, so I stuck it out. It
fired beautifully! Cone 10 dropped top and bottom like they were dancing
together! I don't have a door on the shed and I open half of the roof of
the shed up to vent the stack out of the shed. If the pilots had blown out
it would have shut down, but they didn't even sputter.
Earl Brunner
Cliff Glover wrote:
> ----------------------------Original message----------------------------
> I would like to hear from anyone who has had their gas kiln explode
> during a firing.
Louis Katz on tue 22 dec 98
Why?
Cliff Glover wrote:
> ----------------------------Original message----------------------------
> I would like to hear from anyone who has had their gas kiln explode
> during a firing.
--
Louis Katz
lkatz@falcon.tamucc.edu
NCECA Director At Large
Texas A&M-CC Division of Visual and Performing Arts Webmaster (512)
994-5987
Cliff Glover on wed 23 dec 98
Earl,
Thanks for your honest and candid reply. I think a number of potters have had
similiar experiences when lighting the kiln. Probalby more than we would like
to admit. But I recently had an explosion during a firing--about three hours
into it and I'm somewhat shook up. I have some ideas about what might have
happened but wanted to investigate a bit first to see if kind of accident had
happened to anyone else.
Cliff
Earl Brunner wrote:
> ----------------------------Original message----------------------------
> Cliff, your post brought such funny/not so funny images to mind! For
> instance, I wanted to know why you might be asking? Have you had recent
> experience in this area? I'm sure that there are many stories of
> "accidents". I would guess that most of them came from errors in the burner
> lighting process. I used to have a propane fired, down draft that had a
> stacked brick door that I once blew off (on top of myself). I had forgotten
> to close the valves on all the burners before turning on the gas and it
> built up inside before I got the flame to the burners. Never did that
> again. Broke a lot of those nice soft brick in the door! (They weren't so
> soft either) Once lit and firing I can't think of circumstances that would
> cause an explosion, without some kind of fuel delivery interruption. Most
> commercially manufactured kilns would have to have safety equipment
> installed in order to fire. As a side note, I just fired my Geil kiln out
> in the back yard Saturday to cone ten and we had a wind storm during the
> firing that had gusts to 50 miles per hour. I was well committed into the
> firing when the wind kicked up and on a deadline, so I stuck it out. It
> fired beautifully! Cone 10 dropped top and bottom like they were dancing
> together! I don't have a door on the shed and I open half of the roof of
> the shed up to vent the stack out of the shed. If the pilots had blown out
> it would have shut down, but they didn't even sputter.
> Earl Brunner
>
> Cliff Glover wrote:
>
> > ----------------------------Original message----------------------------
> > I would like to hear from anyone who has had their gas kiln explode
> > during a firing.
Dan Tarro on fri 25 dec 98
Earl,
Something from the past pricks my memory. Something about firing LP and
having too rich of a mix. If this might be a possibility, what I remember
was that in the early stage of firing (below 1000 deg. F), the fuel isn't
broken down H&O and still stays LP. Heavier than air it settles to the
base of the kiln, or worse, the floor of the studio and ignites. BOOM!
Sketchy memory. If there are any seasoned LP users out there that could
shed light on this please do. Are you using LP? This is not my personal
experience, I fire Nat. Gas.
Dan Tarro
Oak Tree Stoneware
Ham Lake, Minnesota
On Wed, 23 Dec 1998 10:51:01 EST Cliff Glover writes:
>----------------------------Original
>message----------------------------
>Earl,
>
>Thanks for your honest and candid reply. I think a number of potters
>have had
>similiar experiences when lighting the kiln. Probalby more than we
>would like
>to admit. But I recently had an explosion during a firing--about three
>hours
>into it and I'm somewhat shook up. I have some ideas about what might
>have
>happened but wanted to investigate a bit first to see if kind of
>accident had
>happened to anyone else.
>
>Cliff
>
>
>
>Earl Brunner wrote:
>
>> ----------------------------Original
>message----------------------------
>> Cliff, your post brought such funny/not so funny images to mind!
>For
>> instance, I wanted to know why you might be asking? Have you had
>recent
>> experience in this area? I'm sure that there are many stories of
>> "accidents". I would guess that most of them came from errors in
>the burner
>> lighting process. I used to have a propane fired, down draft that
>had a
>> stacked brick door that I once blew off (on top of myself). I had
>forgotten
>> to close the valves on all the burners before turning on the gas and
>it
>> built up inside before I got the flame to the burners. Never did
>that
>> again. Broke a lot of those nice soft brick in the door! (They
>weren't so
>> soft either) Once lit and firing I can't think of circumstances that
>would
>> cause an explosion, without some kind of fuel delivery interruption.
> Most
>> commercially manufactured kilns would have to have safety equipment
>> installed in order to fire. As a side note, I just fired my Geil
>kiln out
>> in the back yard Saturday to cone ten and we had a wind storm during
>the
>> firing that had gusts to 50 miles per hour. I was well committed
>into the
>> firing when the wind kicked up and on a deadline, so I stuck it out.
> It
>> fired beautifully! Cone 10 dropped top and bottom like they were
>dancing
>> together! I don't have a door on the shed and I open half of the
>roof of
>> the shed up to vent the stack out of the shed. If the pilots had
>blown out
>> it would have shut down, but they didn't even sputter.
>> Earl Brunner
>>
>> Cliff Glover wrote:
>>
>> > ----------------------------Original
>message----------------------------
>> > I would like to hear from anyone who has had their gas kiln
>explode
>> > during a firing.
>
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Sam Wild on fri 25 dec 98
----------
> From: Cliff Glover
> To: CLAYART@LSV.UKY.EDU
> Subject: Re: kiln explosions
> Date: Wednesday, December 23, 1998 10:51 AM
>
I remember firing an old Alpine two burner kiln in College about thirty
years ago. One of the burners wouldn't stay lit for some reason and the
unlit gas would build up until it was ignited by the lit burner. These were
small explosions and caused no damage, but under different cicumstances the
resulting explosion could be greater.
Leslie Norton on tue 29 dec 98
A different kind of explosion...
Back in school there was an old salt kiln that had been around for a long
time. It had salt dripping off the arch, the back set of shelves were
'glued' solidly in place and the arch was dangerously sagging. It was a
perfect salt kiln and the most beautiful pots came out of it. One of the
students fired almost exclusively in this kiln and during the firings he
would throw almost anything that would burn into the kiln along with the
salt. Shoes, banana peels, peanut shells, all sorts of things went into
that kiln. But one firing I will never forget... It was raining and cold,
there was a low fog so you couldn't see but about 20 feet. The salt fog
was dense, coming out of the stack and it must have been about cone 8... he
reaches into an old Styrofoam ice chest that was half full of water and
pulls out an old dead rat. He throws it into the kiln and BAM, the whole
kiln seemed to grow, the sag came out of the arch and you could hear things
falling over in the kiln (I don't know why the kiln didn't collapse, but it
didn't). He continued up to temperature and threw in the salt.. When the
kiln was opened we found the bag wall had collapsed and most of the shelves
had been blown over, but right in the middle of all this chaos was the most
beautiful pot I have ever seen.
- Les
Lili Krakowski on mon 25 apr 05
The story about the kiln at the college is scary. Assuming it WAS a damper
pushed in too tight, would a passive damper have acted similarly?
Both of the following are theories--based on hearsay and limited experience.
I do mean limited.
But.
1.When raw pots are dried they dry from the outside IN. The outer "skin",
layer, dries first. In a dense fine clay, once that has dried that is IT.
Any moisture on the inside is trapped. If they are dried quickly--because
of hot dry weather, because of sitting on the kiln, etc.-- the outside
dries quicker too. When you put a roast or a cake in the oven the outside
"gets done" first. Whether the oven is set at 300 or 450. Stick in the
food thermometer and amaze yourself how "cold" the inside can be when the
outside already is too hot for the touch. As far as I am concerned same
idea.
I firmly believe that dense, pots of fine clay should be dried under wraps.
Or in a dampbox (such as Styrofoam cooler) The inside WILL dry while the
outside still remains damp/open/unshrunk enough to allow the other moisture
through.
2. Redoubtable Snail gave a clear and wonderful answer to the problems with
refiring. But I have a question.
I was told a century ago that "refired" clay, having gone through the LOI
stages and having gone through the vitrification (if that is the correct
term) of some materials and the melding of others, can, upon refiring
produce NEW gases from its inner self. Which, having no proper room to
escape cause explosions. Is that true? Or a 20th Century myth? Is it only
stuff like underglaze as you mentioned.
Lili Krakowski
Just released from physiotherapy!
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