logan johnson on fri 29 oct 04
Hi Gang,
Well, I've finally stopped crying long enough to be able to get online & ask you all if anything like what happened to me has happened to anyone else. My main kiln had a catastophic meltdown during a bisque firing. This is the first time I have used it since a major overhaul was done to it . ( all the elements replaced, a bottom section added with elements, the kiln sitter moved to the center section, it was in the top section) To make a long & oh so depressing story short my kiln sitter arm went down but the button did not pop up the way it has for the last six years untill I barely touched it.
My roommate had opened the garage door & when I checked the kiln the first time I noticed the arm was down. The light on the front did not appear on. So I went to do a bit of throwing. A few hrs. later I went to check on things & noticed the light was on & boy was the kiln HOT!!!! I quickly turned the switches off & went to look at the kiln sitter & as I went to touch the button ( I have NO clue why I did that) it popped up. It had hung up on the hole edge. After a sleepless worry filled night I opened the kiln in the morning. It was WORSE than I had expected. brand new bricks were a toasty golden brown, ^10 kiln posts I think melted. ^10 shelves have warped & we needn't even go into what happened to the ^6 clay load being bisqued. Kiln shelves have fallen into the walls & bricks were cracked.
If anyone would like to see a picture I'd be more than happy to send one but I warn you in advance it may cause nightmares!!! The picture is NOT for the faint of heart! Has this ever happened to one of you? Does this sound like the kiln sitter malfunction I think it was? YES! I DO realize how lucky I am that the house, kiln, garage DIDN'T burn to the ground & I have my insurance people looking into how much is covered by our renters insurance. the kiln sitter wasn't dirty so nothing foreign caused this to happen. Anybody have any input?
Logan Johnson Audeo Studios
www.audeostudios.com
"Carpe Argillam!!"
Michael Wendt on sat 30 oct 04
Logan,
So sorry.
I had the relays stick shut and overfire a bisque load a bit once, but one
certain way to avoid this is to get a kitchen timer and set it for 20
minutes. Check the pyrometer at 20 minute intervals and record the
temperature on a white board or chalk board near the kiln. If the
temperature rise does not match your expectations, find out why. Relays
stick in the closed (power on) position and as a result, they can continue
to supply power to the elements even after they should not.
Also, the witness cones help to prevent this. All systems fail. Even new
systems fail. We must be vigilant at all times.
Again, my sympathies,
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave
Lewiston, Idaho 83501
USA
wendtpot@lewiston.com
www.wendtpottery.com
Ann Brink on sat 30 oct 04
Logan-I really feel sorry for you. Ask any potter and you will hear that
they too have a tale of disaster to recount. That being said, I have to
tell you what you have probably already figured out: Stay with the kiln, and
double check the kiln sitter! Think of doing a firing just as you would
bathing a baby...you stay right there. Oh, you said you were right there,
and thought the light was out. Sorry, I agree- it's one of life's horrible
experiences. Now...the sooner you can repair your kiln, the better. I know
you can't stand the sight of it in this condition.
Best wishes,
Ann Brink in Lompoc CA
----- Original Message -----
From: "logan johnson"
To:
Sent: Friday, October 29, 2004 6:19 PM
Subject: Kiln meltdown, has this ever happen to you? (sorry looong)
Logan wrote:>
> Well, I've finally stopped crying long enough to be able to get online &
ask you all if anything like what happened to me has happened to anyone
else. My main kiln had a catastophic meltdown during a bisque firing.
........more .
william schran on sat 30 oct 04
Logan wrote:> Anybody have any input?< ..this in regard to a kiln meltdown.
Yeah, I got some input.
First, I'm happy to know there was no fire and nobody was hurt.
Second - I had a kiln meltdown many years ago - back in my early days
of teaching. Finished a night class, kiln hadn't gotten to
temperature yet. Kiln had ALWAYS shut off by the kiln sitter
previously. Came back in the morning - the kiln was GLOWING! Who
knows what cone it got up to. Pots, posts and shelves all one molten
mass. That's when I learned to never go off and leave the kiln and
ALWAYS use cones - NEVER trust the kiln sitter or controller.
Third - Unless you had business insurance, I doubt your renters
insurance will cover this.
Bill
Louis Katz on sun 31 oct 04
We had some switches in graduate school labeled in a counter intuitive
way and someone related to me, no names mentioned, thought they had
turned the kiln off. Saturday we discovered the melted mess. We made
new bricks from insulating fire brick and installed them on Sunday. On
Monday it still needed elements but was otherwise set to go. I was a
coffin style Amaco. I am not sure I would try it with an octagonal but
I have made a jig in the past and replaced some brick with home cut.
I check kilns when it is practical. I don't trust sitter's accuarcy
with glazed ware. But for bisques I let the things go. Sooner or later
I will loose a kiln, but the cost of watching them over a ten year
period for bisques is considerable. They start at different times of
the day and there are plenty of other variables to throw off the end
time.
When I had kiln sitter kilns I would fire my bisque at less than full
power just to prevent the kiln from vastly overfiring. Most Octagonals
won't get to cone 10 with two switches on Medium, but will achieve cone
08.
Have you all seen:
http://www.stoveburner.com/stovetop01.htm
What a fantastic collection of functional form.
Louis
On Oct 29, 2004, at 8:19 PM, logan johnson wrote:
> Hi Gang,
>
> Well, I've finally stopped crying long enough to be able to get online
> & ask you all if anything like what happened to me has happened to
> anyone else. My main kiln had a catastophic meltdown during a bisque
> firing. This is the first time I have used it since a major overhaul
> was done to it . ( all the elements replaced, a bottom section added
> with elements, the kiln sitter moved to the center section, it was in
> the top section) To make a long & oh so depressing story short my
> kiln sitter arm went down but the button did not pop up the way it has
> for the last six years untill I barely touched it.
>
> My roommate had opened the garage door & when I checked the kiln the
> first time I noticed the arm was down. The light on the front did not
> appear on. So I went to do a bit of throwing. A few hrs. later I went
> to check on things & noticed the light was on & boy was the kiln
> HOT!!!! I quickly turned the switches off & went to look at the kiln
> sitter & as I went to touch the button ( I have NO clue why I did
> that) it popped up. It had hung up on the hole edge. After a sleepless
> worry filled night I opened the kiln in the morning. It was WORSE
> than I had expected. brand new bricks were a toasty golden brown, ^10
> kiln posts I think melted. ^10 shelves have warped & we needn't even
> go into what happened to the ^6 clay load being bisqued. Kiln shelves
> have fallen into the walls & bricks were cracked.
>
> If anyone would like to see a picture I'd be more than happy to send
> one but I warn you in advance it may cause nightmares!!! The picture
> is NOT for the faint of heart! Has this ever happened to one of you?
> Does this sound like the kiln sitter malfunction I think it was? YES!
> I DO realize how lucky I am that the house, kiln, garage DIDN'T burn
> to the ground & I have my insurance people looking into how much is
> covered by our renters insurance. the kiln sitter wasn't dirty so
> nothing foreign caused this to happen. Anybody have any input?
>
>
>
> Logan Johnson Audeo Studios
> www.audeostudios.com
> "Carpe Argillam!!"
>
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John Rodgers on sun 31 oct 04
logan johnson wrote:
>Hi Gang,
>
>Well, I've finally stopped crying long enough to be able to get online & ask you all if anything like what happened to me has happened to anyone else. My main kiln had a catastophic meltdown during a bisque firing.
>
Logan, I'm sorry to hear about this.
It't a bit late to tell this story, but I had a melt down like this in
my Alaska Studio. The kiln sitter malfunctioned, and the result was an
overfire and a load of porcelain melted and run down over shelves to the
bottom of the kiln, and everything stuck there. What a mess. Lesson
learned.
Now I always fire so that I am present during the final few hours of the
firing. I always fire with a pyrometer. I don't trust them, but they are
good indicators. I always fire using a shelf cone. Once ti begines to
bend, I check the cone every few minutes. When it is where I want it to
be, I turn off the kiln. OR I may let the kiln sitter cone do the job
for me, but I always know where things are time wise.
Not much you can do now but rebuild the kiln or replace it.
Best of luck to you,
Regards,
John Rodgers
Chelsea, AL
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