mel jacobson on tue 4 jan 11
again, it is hard for me to believe that folks
building kilns in 2011 do not have a clue about
flue size.
i had a guy email me the other day...could not make
temp in his kiln. he had a 96 square inch flue, and would
not change it. i called him, tried to explain..but some
dork said `you have to have a big flue to make it work`.
god, it was as big as a wood fired kilns flue.
two burners, like a 50 cube kiln, natural gas.
i suggested 32 sq inches. he thought i was crazy.
but, who cares? his gas, and he cannot make temp.
who is correct?
all of the energy of his kiln was going up the stack.
my god, hold the heat in the kiln, not up the stack.
hard to catch up even with big burners. simple physics
problem, if you let more heat out of the kiln than you can
push in...kiln will not make temp. duh.
nils' book explains it all in detail. and, it is his birthday
this week...he is 97 years old (he is really a lot older than me..
he would be pleased
to hear from `all of you`. he is becoming a doddering old
fool, but still holds some interest. newlywed.
mel
from: minnetonka, mn
website: http://www.visi.com/~melpots/
clayart link: http://www.visi.com/~melpots/clayart.html
new book: http://www.21stcenturykilns.com
alternate: melpots7575@gmail.com
mel jacobson on thu 6 oct 11
thanks nils for your post on flue size.
it is amazing how many people have told nils and mel how
there would be blown up kilns all over the place because
of the double venturi system... 35x40 inches. and, that sure can
be a + or - size...but not too much change.
`that won't work, it is too small...kiln won't heat up.
bad idea and the kilns will explode.`
well, things are running very well. total efficiency kilns.
i have built about ten of them, and sent plans to
hundreds. nils has done many more, with his plans sent
to many hundreds.
our small kiln at the farm with perfect balance is
the standard minnesota flat top. small flue/double venturi.
it could not be improved upon. a perfect kiln.
it is the `feature kiln` in our book and it works like a charm.
it was just by luck that the first stoneware kiln i built
had a 35x40" flue. i just did not know how to bridge
the flue, so i left it small...it worked like a champ.
55 years of firing a small flue kiln. (i love to tell folks
that nils copied my kiln flue in 1962. (not true))
it has more to do with folks like jt abernathy and others
that used logic and industrial concepts.
i seem to remember that if you do the math in the leach
book a standard kiln would have a 36 foot stack. ( i know
it would not fit into modern standards..) i have not found
many kilns that would need over ten feet of stack/12 inch.
many of the standard down drafts would fire nicely with
five feet of stack.
most stacks are determined by roof clearance and total height
of the ridge of a building.
does not have much to do with firing efficiency. many are just
too big.
from: minnetonka, mn
website: http://www.visi.com/~melpots/
clayart link: http://www.visi.com/~melpots/clayart.html
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