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firing a kiln (long)

updated sun 31 aug 97

 

Mel Jacobson on sat 9 aug 97

when i first decided to build a kiln:

i was a rookie, total rookie, had never seen a kiln made with
ifb. had a plan from jim mckinnel in iowa....i think he is the
grandfather of ifb.

wanted to get gas to the garage. i called the gas company.
they said, "hell, it won't work, you want to go how hot?, hell
your crazy"....so, i turned off the meter, got a hack saw, cut the
pipe, put in a T and ran a pipe underground to the studio/garage.
1 1/2 inch line. normal house meter. nice long tapered threads,
hand cut. doped them up good. real good, added three shut offs. have
used it for
almost 30 years.... more gas than i need. i use two 500,000 btu
old denver burners. natural gas, low pressure. have a nice
new flat top/ about 45/50 cubic feet. same burners and gas
system, lots of room around the
edges for gas and heat to move. i never pack tight...rather
have good pots than lots of poorly fired pots. have never
measured how much gas it takes to fire...one pot pays for
it. and who cares....? i like to fire for 10 hours or so..when
the kiln is done i shut it off.

the funny thing about doing my own stuff....i learn a lot.
also found out that i use less gas than my neighbors..really.
of course a gas meter can only measure so much gas, and
when i am firing, well, the , well, maybe it, sorta slips by the
meter. that is why the gas company wants a 3" pipe...they can
measure it more accurately. i think they lose a lot in small
meters. gas folks want to sell you lots of gas...potters want
to mix gas and air...air is free. that is why i love my old denver
burners...they have a bell on the back to control the primary
air....on threads, can close them tight or open all the way.
i like to be able to control air....use it to my advantage.
i also like to be able to control the flue...have a nice kaowool
board slide damper. have it marked up... pencil marks...windy,
low
pressure, no wind, cold, hot day etc. makes a difference.

people like to have a pat answer. people like simple answers,
people like you to give them answers.....like, "where do you
put your damper during the firing?" i always say. "hell, i don't
know?" depends on the day. what i am firing, what i am doing.
changes every time i fire. the oxyprobe is nice. but it cannot
control the weather.
for example:
cloudy day, winds 25-30 mph. light snow, minus 3 degrees F.
and i have all red and temmoku and celedon in the kiln.
next example:
clear, no wind, 93 degrees F. and the kiln is full of rhodes 32.
are you going to fire the same? notice any factors that are
different? the life of the potter is not simple...it is not about
looking for a nice cone 6 clear. (anyone have a good recipe?)
making pots is a challenge, it is going to war when you fire
a big gas kiln...do you have a lot of notes, instructions, sheets
of paper with ides written on them? throw them into the kiln
and use them for fuel, best use for them. then try everything
uner the sun... fire with one burner, two burners, high gas, low gas
can you move the heat in your kiln...get it top, bottom, left or
right. can you pivot your burners..put bricks in the heat
path, take them out, change locations....and memorize in
your head what has happened. learn to "drive" your kiln
just like an airplane. drive it, make it do what you want...
and don't let it control you! or call nils from boston at your
seven o'clock a. m. and ask him. ( it will be 3 a. m. oregon, he
loves that)
and if you want motorized, blowers, gas burners, and that stuff, call
marc ward, or buy from nils, or johnson....they are nice, expensive,
but will serve you well... but you will also have to learn how
to drive those kilns.

there is no perfect schedule....only experienced potters, both
men and women, grown ups that learn their craft and love
the challenge of every day potting. that is why a potter is a
combination of artist, craftsperson, scientist, engineer and
general purpose mechanic. and that is why i love it... never
a boring minute in my life. memorize what i just told you,
you have to pass the biggest test, your kiln.

http://www.pclink.com/melpots

Giddings, Maxine on thu 14 aug 97

Hello, Mel, Nils, and all who replied to my inquiry about building a
kiln for Clayworks Potters Cooperative. Clayworks is a 17 member co-op.
We have an old sprung arch, gas-fired kiln with four Venturi burners
that were installed in 1992. The kiln was installed perhaps in the
sixties. We are located in the basement of an old library. The kiln
size is about 32 or 36 cubic feet. We need to rebuild as I said before.
We are getting a bit confused now, reading the arguments about flat top
vs. arched kiln. Some of us are negotiating about building a cautionary
arch.
How good is the Minnesota Flat top for cone 10 reduction firing.
Does it fire evenly in reduction. Can you tell us anything about the
advantages or disadvantages of the arch over the flat top for a co-op.
Also, we are thinking about patching our old one ( as one member finally
learned to fire our best reduction ever in the old thing - any
suggestions for tearing down the old and reusing whatever is good as
this will be a cheaper possibility?).
How old do soft bricks have to be before applying ITC coating.

If we fire to cone 10 and one half, should we still purchase the
more expensive soft brick if we intend to coat the inside.
We complete about fifteen firings per year in our gas kiln at
the co-op.
One of our members attended NCECA and met Nils there. She
provided most of these questions. Her name is Anne Klein. I am Maxine
Giddings. Thanks for all help. We are ready to make a decision once we
have gathered exhaustive info.
> -----Original Message-----
> From: Mel Jacobson [SMTP:melpots@pclink.com]
> Sent: Saturday, August 09, 1997 7:36 PM
> To: Multiple recipients of list CLAYART
> Subject: firing a kiln (long)
>
> ----------------------------Original
> message----------------------------
> when i first decided to build a kiln:
>
> i was a rookie, total rookie, had never seen a kiln made with
> ifb. had a plan from jim mckinnel in iowa....i think he is the
> grandfather of ifb.
>
> wanted to get gas to the garage. i called the gas company.
> they said, "hell, it won't work, you want to go how hot?, hell
> your crazy"....so, i turned off the meter, got a hack saw, cut the
> pipe, put in a T and ran a pipe underground to the studio/garage.
> 1 1/2 inch line. normal house meter. nice long tapered threads,
> hand cut. doped them up good. real good, added three shut offs.
> have
> used it for
> almost 30 years.... more gas than i need. i use two 500,000 btu
> old denver burners. natural gas, low pressure. have a nice
> new flat top/ about 45/50 cubic feet. same burners and gas
> system, lots of room around the
> edges for gas and heat to move. i never pack tight...rather
> have good pots than lots of poorly fired pots. have never
> measured how much gas it takes to fire...one pot pays for
> it. and who cares....? i like to fire for 10 hours or so..when
> the kiln is done i shut it off.
>
> the funny thing about doing my own stuff....i learn a lot.
> also found out that i use less gas than my neighbors..really.
> of course a gas meter can only measure so much gas, and
> when i am firing, well, the , well, maybe it, sorta slips by the
> meter. that is why the gas company wants a 3" pipe...they can
> measure it more accurately. i think they lose a lot in small
> meters. gas folks want to sell you lots of gas...potters want
> to mix gas and air...air is free. that is why i love my old denver
> burners...they have a bell on the back to control the primary
> air....on threads, can close them tight or open all the way.
> i like to be able to control air....use it to my advantage.
> i also like to be able to control the flue...have a nice kaowool
> board slide damper. have it marked up... pencil marks...windy,
> low
> pressure, no wind, cold, hot day etc. makes a difference.
>
> people like to have a pat answer. people like simple answers,
> people like you to give them answers.....like, "where do you
> put your damper during the firing?" i always say. "hell, i don't
> know?" depends on the day. what i am firing, what i am doing.
> changes every time i fire. the oxyprobe is nice. but it cannot
> control the weather.
> for example:
> cloudy day, winds 25-30 mph. light snow, minus 3 degrees F.
> and i have all red and temmoku and celedon in the kiln.
> next example:
> clear, no wind, 93 degrees F. and the kiln is full of rhodes 32.
> are you going to fire the same? notice any factors that are
> different? the life of the potter is not simple...it is not about
> looking for a nice cone 6 clear. (anyone have a good recipe?)
> making pots is a challenge, it is going to war when you fire
> a big gas kiln...do you have a lot of notes, instructions, sheets
> of paper with ides written on them? throw them into the kiln
> and use them for fuel, best use for them. then try everything
> uner the sun... fire with one burner, two burners, high gas, low gas
> can you move the heat in your kiln...get it top, bottom, left or
> right. can you pivot your burners..put bricks in the heat
> path, take them out, change locations....and memorize in
> your head what has happened. learn to "drive" your kiln
> just like an airplane. drive it, make it do what you want...
> and don't let it control you! or call nils from boston at your
> seven o'clock a. m. and ask him. ( it will be 3 a. m. oregon, he
> loves that)
> and if you want motorized, blowers, gas burners, and that stuff, call
> marc ward, or buy from nils, or johnson....they are nice, expensive,
> but will serve you well... but you will also have to learn how
> to drive those kilns.
>
> there is no perfect schedule....only experienced potters, both
> men and women, grown ups that learn their craft and love
> the challenge of every day potting. that is why a potter is a
> combination of artist, craftsperson, scientist, engineer and
> general purpose mechanic. and that is why i love it... never
> a boring minute in my life. memorize what i just told you,
> you have to pass the biggest test, your kiln.
>
> http://www.pclink.com/melpots

David Woodin Set Clayart Digest on fri 15 aug 97

I would coat your old kiln with ITC 100, then patch with ITC 200, this will
get you by until a decision is made about rebuilding the kiln. We recoated
ours a year ago and now have no need to rebuild it. Much cheaper too and it
fires better then it ever did.