mel jacobson on mon 30 aug 99
people, very different.
and i do not generalize too much about kilns.
so, with that in mind.
secondary air comes from your openings in the kiln around the burners etc.
primary air comes from the back of the burner or blowers.
many kilns have really big holes to fit the burners in....and some people
stick the burner right in the kiln. the burner ports can be too big and allow
too much secondary air into the kiln. so, check that.
the damper controls the amount air and heat allowed out of the kiln.
if you let more air and heat out than you let in...well, no heat rise.
a 9x9 inch flue really sucks...really. try 5x6 it works better.
so, to get reduction you must control the amount of secondary air, primary
air, damper position and very important...the amount of fuel going in.
most often you will not get back pressure from the bottom spy ports.
i almost never do...i always have one spy hole in the end of the kiln...half
way up.
that is my reduction back pressure gauge. i always use the same port.
when the flame is about 5 to 7 inches long i figure that the kiln is in
good reduction.
now, i can turn up the gas to get that flame, push in the damper, or
i can make smoke by turning down the primary air.
i do all of the above....slight move in with the damper, turn up the gas,
roll in the bellows on my burners, and of course i have a ports for the burners
that are only slightly bigger than the end of the burner, and the burner is
backed off 2 inches.
then i read the oxyprobe....i always set my flame from the spy hole first.
get the kiln in comfortable reduction. i then go outside, check the top
of the stack..no smoke. ( i just loved tom wirt's post on nils' theory of
waves inside the stack...catch a wave in the wrong place..no heat rise.)
then i make very slight adjustments using the probe. i have two probes..
(i know, smarty pants. but, nils made me do it.) old aussie, and new
axner...they read the same.
at about cone 010 i reduce at 3.5 on the probe. at about cone 1 i jack
it to 6.0, or just under.
when doing shino i try and get reduction early, but man, that is hard. the
kiln
is not really coook'n, so i throw in wood, paper, and make smoke for just
a few minutes..get away from the kiln.
that is how i carbon trap...but, be careful...you do not have to stand around
and watch the damn thing burn.
i always love to watch potters stare at a kiln, maybe for 6 hours...just stand
there and stare. we are a goofey lot.
anyway, when you open the kiln you will sure know if you have reduction.
red's are a sure sign. speckles in the glaze from the body.
and of course judge body color. celedons will also tell you a great deal.
i am not sure why jeff wants really light reduction...that is harder to
control.
medium should be the easiest...sorta 5.5-6.0 on the probe.
and, why not keep the kiln in reduction all the way from 011.?..it won't hurt
a thing.
time, experience, a good tool as the probe is, will save you tons of money.
can't figure out why people will not buy good tools, and then piss and moan
cuzz they had a bad firing.
sorta like a 2,000 dollar computer and no surge protector...( hell, i have
three,
one to the power, then i hook one protector to that one, then plug the
computer and phones into the third one.) 25 bucks worth of protection
to 2,000 dollars worth of electronic tools...easy to figure.)
how you stack the kiln may have as much to do with perfect reduction
as primary and secondary air.
god, make sure you get every pot in every firing...squeeze, re-stack.
brag about how many pots you can fit in.
false economy.
do that...stack tight.
but, don't whine about bad firings...and then shovel the crap into the dust
bin.
and, if you want to be smart...listen to ron roy, monona, craig and many
others....they are working for you.
they are not the enemy.
almost everything that i know about kilns has come from nils...
and that is a gift that i cherish.
i listen to marc ward, he is a smart guy.
knows his business.
how lucky we are to have cameron behind us....with great info.
yes, this is a great list.
a miracle in many ways.
and we have dannon there to smack us if we get to smart with our mouths.
and joyce will really get you if you don't watch out..(hey, hey, i really love
california, great place...i would even live there for a couple of days.
really.)
but, see, i get really nervous when things are not all green around me.
i like rain, cold days. snow...gray and black trees, and i like the idea
that the weather will change every 35 minutes.
mel/mn
http://www.pclink.com/melpots
from minnetonka, minnesota, u.s.a.
millie carpenter on tue 31 aug 99
mel
I learned to load kilns in a community college and was taught to really stack
tightly in the gas and the electric. does it matter how you loose or tightly yo
load an electric. or I think that I am really asking what effect if any there ar
depending on how it is loaded because it is radient rather than a flame.
> ..stack tight. but, don't whine about bad firings...and then shovel the crap i
> the dust bin.
Millie in Md waiting to see if my NC in-laws will wind up with water front prope
by the end of the hurricane season.
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