Ken Nowicki on mon 2 aug 04
anyone?
Dear Clayart friends,
Listen, I wouldn't bother asking you all this if I could put my finger on
Fred Olsen's "Kiln Book" if I knew where it was in the sea of boxes still packed
away in my basement (soon to be my "clay studio"... I hope) because I'm pretty
sure Fred lays out in his book on how to do this... but since I don' t have
it handy right now... I thought I'd put the question out there and see if any
of you who know how to do this wouldn't mind responding.
I've been thinking more and more about Steve Mills's post about the exit flue
hole cut into the lid of an updraft drum kiln that was a "slot" rather than
the standard round hole. (see 06/23/04 "Re: Uneven Kiln Temp") and I'm thinking
of doing this to the kiln I'm building.
.....................................................
Steve Mills wrote:
"Finally I have a slot in the lid rather than a round hole. With the
latter the (still) circulating fire arriving at the top forms a cone
shape and exits too easily leaving a very cool area at the top. With a
slot, the fire has to change direction substantially so the slot becomes
a passive baffle retaining much of the heat that would otherwise be
lost. Also with a slot it is possible and easier to control the
atmosphere and the speed of the firing, which helps to conserve fuel.
With a Kiln set up as above, I have regularly fired in reduction to cone
9 at the top and effectively 9 and a half at the bottom."
......................................................
As I've mentioned before, I'm working on a "hybrid" kiln project this summer
with L&L
and I thought this idea of a "slot" rather than a typical round hole cut out
in the lid was an ingenious thought, and I'm seriously considering doing this
rather than drilling a round hole. If nothing else, just from the ease of
controlling the draft (by sliding a piece of kiln shelf or other refractory
material) over the slot seems like it would give the user much more control over
adjusting the draft in the flue rather than spanning the diameter of a circle,
easier too. Any further benefits that Steve mentions above would be "icing on
the cake".
As far as cutting the slot, I would imagine it could be performed quite
simply by using a router and router bit in the soft firebrick.
Okay... so here's my big question...
How can I calculate the width and length of the slot to be cut, to properly
match the burner port opening for optimum air flow?
I know there must be a way to calculate this, and I thought I saw it once in
Fred's book, but as mentioned, I can't put my finger on my copy just now.
Being somewhat "mathematically challenged" makes it even more daunting for me...
so any of you who know how to do this... go "easy on me"...
..............................................
Specs:
My burner port opening at the center bottom of my kiln will be a rectangle of
2"inches wide X 2 1/2" inches tall. These were the recommended measurements
that Marc Ward gave me for the burner system I'm using... which is a small
Ransom B1 burner with target pilot. I'm using L&L's JD230 kiln with the 3" thick
firebrick. (6.67 cu. feet)
..............................................
Thanks in advance for all your help and suggestions. I feel truly blessed to
be a member of such a great ceramics community!
Best regards,
- Ken
"...getting excited here, as I make the final preparations for gathering all
my materials and necessary equipment to finally get to the "construction
phase" of this kiln. I'm planning on driving out to Philadelphia to L&L's factory
at the end of August to join Steve Lewicky and begin putting this kiln
together... whoo hoo!"
Kenneth J. Nowicki
Port Washington, NY
RakuArtist@aol.com
Charter Member/Potters Council
(*This message has been "reposted" since Clayart went down over the weekend -
originally sent on 07/31/04)
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