mel jacobson on fri 30 oct 09
it is interesting that several very nasty kiln disasters and
studio fires have been caused by folks/students over reducing.
it happened at the Univ of Minnesota with a brand new kiln.
kid stuck a pencil in the auto shut off damper spring/then proceeded
to shove that damper almost all the way in. turned up the gas pressure.
`he wanted dark reduction`.
that kiln blew up like a bomb. spill over heat got to the concrete
floor and blewwweeeee. why he was not killed is a mystery.
and the answer to the question is: `why?`
over reduced pots are usually really ugly.
not to mention the danger of all that smoke and flash back.
(in this case, he may have wanted that fake wood kiln look.
and we use the term `fake` as in stupid.)
i did a kiln consult on a kiln that when firing had a
32 inch flame coming out of the lower port during reduction.
`hey, isn't that normal?` i measured that flame with a tape.
just to make sure.
why they did not burn down that studio is beyond me.
controlled reduction is critical when firing a fuel kiln.
in most cases, a flame of about 3 inches from the mid port is all that is
necessary.
and, turning up the gas pressure to max is usually not a sensible
thing to do. kilns usually stall with too much gas pressure. again,
i cannot tell you how many kiln consults i have done where all i
had to do is turn down the gas pressure, and up the temp
went like a rocket. people think that a kiln is like a race car, the
more you push down the gas peddle, the faster it will go.
of course the reverse is true if you have a 90 inch flue. all the
heat is up the stack.
of course, if you have un/trained techs/kids with no experience running
kilns...that race car mentality will take over in a heart beat.
this entire topic goes back to my take on teaching ceramics.
if the teacher does not know how to fire, the kids will sure
mess it up big time. no person should be firing a public kiln without
gobs of knowledge, skill and understanding. a quality, well trained tech
is one of the cheapest hires in any institution. it will pay back a hundre=
d
times. taking someone off the street and having them fire a gas kiln
is in the `really stupid range`.
the one thing i have noticed here on clayart is:
most of the folks that are teaching, and reading clayart and
contributing to us, are doing the right thing....gathering and
giving quality information. you know their program is in great shape.
when living and teaching in the world of craft, you must train, inform,
create a skill set, then get out of their way...they will do the rest.
art and creativity, and safety come after the training, not before.
mel
i am firing my gas kiln this morning. i approach it like a pilot
flying a plane. check list, do all the checks, then do it again.
it is like going to war. being stupid and careless will get you killed.
from: minnetonka, mn
website: http://www.visi.com/~melpots/
clayart link: http://www.visi.com/~melpots/clayart.html
new book: http://www.21stcenturykilns.com
Les Haworth on fri 30 oct 09
In my kiln repair business I came across a woman who fired her schools gas
kiln to cone 5.
During one firing she accidentally closed the damper nearly shut and left t=
o
use the restroom.
Luckily the students had gone home for the day when the kiln blew up.
Perfectly good updraft kiln nearly destroyed.
Fortunately, the arch was the only thing I had to rebuild.
I also gave the instructor some dos and don'ts relating to firing a gas
kiln.
She had inherited the kiln from her predecessor and wasn't really intereste=
d
in reducing her student's ware.
I told her to have the school buy her an electric kiln.
Haven't heard from her since.
Les Haworth
Technical Support
Laguna Clay Co.
(Back in the saddle again)
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