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whose flues

updated wed 30 jan 08

 

David Hendley on mon 28 jan 08


Last year I reduced the size of the exit flue in my
fast fire-style wood kiln, and it has improved the
firing.
I am of the school that says 'make the flue larger than
you think it needs to be - it is simple to make it
smaller but almost impossible to make it larger.'

Before the adjustment, it was at 90 square inches.
I inserted a couple of bricks to reduce it to 60. I
also started using a 'trick brick', as Olsen calls it in
his book. At somewhere around 2100 degrees, I put
a steel rod through a hole in the side of the kiln and
move a brick over, to open the flue up a little more.
It adds an extra 12 square inches.
Adding that extra area makes it noticeably easier
to increase the temperature at a faster rate.
Something about wood fire flames increasing in
volume as they get hotter?
It has also helped in my quest for copper reds.

The kiln is about 40 cubic feet total, 24 cu. ft. of
stacking area.
While we're talking costs, a ^10 firing costs me
about $8, at 48 cents a mile, to drive the '79
Ford pick up to the pallet mill and back with a
load of wood.
The thrill of seeing flames roaring out of the fireboxes
at cone 10 - priceless.

David Hendley
Maydelle, Texas
david(at)farmpots(dot)com
http://www.farmpots.com

Bill Merrill on tue 29 jan 08


David,

=20

My stoneware kiln is about 65 cubic feet. The flue opening is 5' X 9"
or 45 square inches. I still damper during firing down to an opening
about 1.2" .

=20

Most potters have had it drummed into their head that a huge flue
opening is what it takes. Usually not. I have a couple of floor
systems that make most any stoneware kiln fire better, better reduction
control and better heat distribution. My stoneware kiln is over 5 feet
tall in the firing chamber and the heat is the same top and bottom.

=20

If anyone wants pictures send me an email.

=20

Bill Merrill billm@pcadmin.ctc.edu

=20

-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of David
Hendley
Sent: Monday, January 28, 2008 4:23 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: whose flues

=20

Last year I reduced the size of the exit flue in my

fast fire-style wood kiln, and it has improved the

firing.

I am of the school that says 'make the flue larger than

you think it needs to be - it is simple to make it

smaller but almost impossible to make it larger.'

=20

Before the adjustment, it was at 90 square inches.

I inserted a couple of bricks to reduce it to 60. I

also started using a 'trick brick', as Olsen calls it in

his book. At somewhere around 2100 degrees, I put

a steel rod through a hole in the side of the kiln and

move a brick over, to open the flue up a little more.

It adds an extra 12 square inches.

Adding that extra area makes it noticeably easier

to increase the temperature at a faster rate.

Something about wood fire flames increasing in

volume as they get hotter?

It has also helped in my quest for copper reds.

=20

The kiln is about 40 cubic feet total, 24 cu. ft. of

stacking area.

While we're talking costs, a ^10 firing costs me

about $8, at 48 cents a mile, to drive the '79

Ford pick up to the pallet mill and back with a

load of wood.

The thrill of seeing flames roaring out of the fireboxes

at cone 10 - priceless.

=20

David Hendley

Maydelle, Texas

david(at)farmpots(dot)com

http://www.farmpots.com

=20

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