[Clayart] dampers and flues

mel jacobson melpots2 at visi.com
Fri Jul 14 07:39:30 EDT 2017

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 needed.
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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