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free space in the kiln

updated sat 25 dec 10

 

Larry Kruzan on fri 24 dec 10


Hi Kiln Builders,

I'm designing a propane fired reduction kiln that my son and I are building
over my winter break. This kiln will have a welded steel frame and - hold
your breath - a REAL swinging door!!! Ok, you can breathe again. As I'm
planning the design, I'm looking at how much free space to have around the
shelves. The flame trenches on each side of the of the shelves are
established but I'm not too sure how tight the door should be against the
shelves.

My current kiln has about 1" between the shelves and the back wall and when
the door is stacked there is 1-2" between the door brick and the shelves.
I've often wondered if this was too tight and now I have the chance to
change it, if it would really matter. It would be a half a brick deeper -
that would add a lot more room for circulation - but it might be too much -
what do you think?



Larry Kruzan

Lost Creek Pottery

www.lostcreekpottery.com

Vince Pitelka on fri 24 dec 10


Larry Kruzan wrote:
"I'm designing a propane fired reduction kiln that my son and I are buildin=
g
over my winter break. This kiln will have a welded steel frame and - hold
your breath - a REAL swinging door!!! Ok, you can breathe again. As I'm
planning the design, I'm looking at how much free space to have around the
shelves. The flame trenches on each side of the of the shelves are
established but I'm not too sure how tight the door should be against the
shelves. My current kiln has about 1" between the shelves and the back wall
and when the door is stacked there is 1-2" between the door brick and the
shelves. I've often wondered if this was too tight and now I have the chanc=
e
to change it, if it would really matter. It would be a half a brick deeper =
-
that would add a lot more room for circulation - but it might be too much -
what do you think?"

Larry -
I think that the only condition regarding too much space around the set (th=
e
combination of shelves, posts, and wares) might be that it creates an easy
path for the heat directly to the flue. I like to have 1.5"-2" clearance
front and back. If your burner ports are in the side walls with the flames
aimed directly towards the wares then of course you will need bagwalls and
should have that clearance between the lower shelves and the bagwalls. If
the burner ports are coming in the front or rear corners with the flame
passing along the side walls, then you do not need bagwalls and can save
considerable room, and same if the burners ports are in the floor along the
side walls. You would still need a combustion zone, and usually in such a
case the shelves are at least 6" from the side walls.
- Vince

Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka