mel jacobson on fri 12 sep 03
i just got a note from a clayarter asking
how i pack kilns. she feels embarrassed
as she follows a system that i use.
she was blown out of the water by `tight packers`.
i am leaning much more to loose packing.
where i kept pots an eighth of an inch apart
in the old days, i now leave `always` a thumb
width.
i have seen many pots ruined in kilns because
the potter had to get `every damn pot in the studio`
in the firing.
what is the rush? if you ruin them, why not wait
til the next firing. public studios are the worst.
good pots ruined because the tech over loaded the
kiln. they take pride in getting far too many pots
in the kiln. i would assume the tech would be proud
of perfect firings. every pot fired to a perfect potential.
when you over load, heat dams are formed...no air
can move through the kiln. same for big bag walls.
they just stop the flow of heat and air.
when i am hired to help problem solve a kiln, the first thing
i do is check for overloading. it is the most common enemy.
tight shelves, too many pots, pots crammed in front of the flu.
and, shelves far too big for the kiln...touching the side walls
and they use dog bone supports for the base. (less than an inch)
i call them greed kilns. packed like a hong kong apartment.
i suggest a full fist of air space around the perimeter of the kiln.
three inches at least on the bottom...and 5 inches at the top
of the kiln. four to five inches at the flu.
nils has been a strong proponent of letting air flow
and heat have room to get through and out of the kiln.
i agree with him. and, remember, you can trap heat
i an electric kiln as well as a fuel kiln. tight shelves
are the most common contributor.
since i have been `down firing`, and opening up the spaces
between pots, my failure factor has been reduced to almost
zero.
i never, never fire a kiln with parallel shelves...always staggered.
the only kilns i overstack is bisque firing...and that too can
create problems. ron has suggested that over packed bisque
can be underfired and gases cannot escape.
some of the best total firings we have had at the farm over
15 years have been lighter loads.
mel
From:
Minnetonka, Minnesota, U.S.A.
web site: my.pclink.com/~melpots
or try: http://www.pclink.com/melpots
new/ http://www.rid-a-tick.com
Lois Ruben Aronow on fri 12 sep 03
On Fri, 12 Sep 2003 05:20:13 -0500, you wrote:
>i just got a note from a clayarter asking
>how i pack kilns. she feels embarrassed
>as she follows a system that i use.
>she was blown out of the water by `tight packers`.
I used to be a "tight packer", but no more. I agree, what's the rush?
I love loading the kiln, as it's kind of like a puzzle. In fact, I
have always used to thumb rule, and considered THAT to be tight
packing. =20
I have another variable in my mix - my glaze spits, so I have to keep
colors separate, and not vary the heights, so beads don't spit into
the insides of other pots. But then I also get a better firing using
half shelves and staggering - better heat circulation. What's a girl
to do?
>nils has been a strong proponent of letting air flow
>and heat have room to get through and out of the kiln.
>i agree with him. and, remember, you can trap heat
>i an electric kiln as well as a fuel kiln. tight shelves
>are the most common contributor.
Thanks for saying this. It's just as important in an electric.
>the only kilns i overstack is bisque firing...and that too can
>create problems. ron has suggested that over packed bisque
>can be underfired and gases cannot escape.
I used to really load up my bisque, but I try and let bigger things
breathe without other stuff stacked on them. I do stack pots inside
of others, but don't really consider that loaded. I know potters who
just sort of tumble stack for a bisque firing, and that has never
worked for me. Too many broken pots.
My clay work has definitely taught me a very important lesson -
patience. =20
...Lo
who will indeed be loading a glaze today.
************
www.loisaronow.com
=46ine Craft Porcelain and Pottery
New Work for Summer 2003
New Show and Retail information
Kathi LeSueur on fri 12 sep 03
melpots@PCLINK.COM wrote:
> i
>
> i suggest a full fist of air space around the perimeter of the kiln.
> three inches at least on the bottom...and 5 inches at the top
> of the kiln. four to five inches at the flu.>>
> Perhaps it is the use of the Abernathy kiln, with no flue, no bag
> wall, seven inch of space from kiln wall to shelves, that allows us
> using this design to pack so tightly. My experiences has been just the
> opposite of your.
> Kathi
>
>
>
>
Paul B on fri 12 sep 03
Mel,
I have been following this advice as well with good results, except the top
of my kiln is always a little cooler. Usually i can work around it by
putting the right glazes up there, but i would really like to get it at
least a half cone or more hotter there. I leave plenty of space up there
between the pots and the roof, but it is still cooler. Have two burners
coming in from the back with one target (half) brick in the middle of each
flame trench. Bottom of kiln is always one to two cones hotter. Have you
ever had to deal with this problem? if so i would be most thankful to hear
of the solution you came up with. thanks!
Paul B
Falmouth, KY
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