[Clayart] dampers and flues

Tom Sawyer tsawyer at cfl.rr.com
Mon Jul 24 15:26:04 EDT 2017


Still lurking. A few years older and tribulation fought through this past
year including back surgery. Switched to some hand building but I am now
able to throw again. I just put together a portfolio of work that I have
done in the past couple of years. If your interested as one of my mentors,
I'll send you a file.

Thomas Sawyer, M.D., J.D.

-----Original Message-----
From: Clayart [mailto:clayart-bounces at lists.clayartworld.com] On Behalf Of
mel jacobson
Sent: Friday, July 14, 2017 7:40 AM
To: clay <" clayart"@lists.clayartworld.com>
Subject: [Clayart] dampers and flues

in my opinion, when building a kiln you have to be able to change the size
of your flue outlet, and try to think of nils and the idea of turbulence at
the flue.

even with higher altitude if the flue opening is too big, you just heat the
atmosphere. so, saying that...you should be able to take out a partial
brick, or add a partial brick until you get it firing just right.  i would
stay in the 40 square inch area to begin. just don't get in the 70-80 square
inch size that so many old books talk about. it is just too big.  fuel is
expensive...why waste it for nothing.

there is a reason our kilns fire so fast...like 5 hours.
the flue and stack are just perfect.
you can always fire longer, slow it down...but..when you have to fire a 15
cube kiln for 18-24 hours...there is a problem..big problem.  it is your
money going up the stack.
learn to down fire..your life gets better.

bill schran, dave lyons and others were firing our small kiln to cone 11 in
under 5 hours. 6 days in a row.
the kiln is in perfect balance. it is a one brick thick kiln. two stacks of
shelves. 11x16's. mn flat top.
kiln is made mostly of broken and rubble bricks. the needle on the gas gage
barely moves.  but, a great many people fight us like made...can't be
true...well, it is.

we like to tell people that the kiln is done before the outside of the
bricks get really hot.  it is true.

colleen and lynn fox, with john post built that kiln in two days. ben
burgert age 16 was the strong kid that did all the lifting. we used sacrete
to tie the block to the ground...level. it is rocky and sandy.  no slab
the next summer we built a wooden frame with a metal roof over the kiln.
nice little shelter.  cost was under a hundred bucks. (you buy that steel
roofing that is left over from other jobs...you know, in the corner of the
lumber yard...`hey joe, you want to get rid of that steel roofing?
4/3 foot by 8 feet. who cares what color.

we fire about 45 pots or more, in five hours and the cost is about 20 bucks
for propane. do the math.
my 45 cubic foot natural gas kiln fires for the cost of a mug. true.  there
is a reason i did not get a bigger meter.
that kiln fires in 9 hours, i do not rush it. that is the timing it has
always had. big kiln, lots of pots and shelves to heat up.  about 100 pots a
firing. (size matters when counting., of course.)

Mel's Website:  www.melpots.com


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