gafergus on sun 27 oct 96
I am finally getting around to building a garbage can raku kiln. I am
wondering where the flue hole in the lid needs to go. Does it need to go
right in the middle or sould it be placed to one side so that a circular
air flow can be created?
Any help would be greatly appreciated!
Thanks
Gary Ferguson
chull@startext.net on mon 28 oct 96
gafergus wrote:
>
> ----------------------------Original message----------------------------
> I am finally getting around to building a garbage can raku kiln. I am
> wondering where the flue hole in the lid needs to go. Does it need to go
> right in the middle or sould it be placed to one side so that a circular
> air flow can be created?
>
> Any help would be greatly appreciated!
>
> Thanks
> Gary Ferguson
Gary,
Generally it goes in the center and is about 5"-6" in diameter. I have
never seen one off-set or on the side. Be sure to place a block (shelf
post or part of a brick) about 6" in front of the burner opening to
split the flow for better circulation.
Cynthia
TX
lrh on mon 28 oct 96
______________________________ Reply Separator _________________________________
Subject: Garbage Can Kilns
Author: Ceramic Arts Discussion List at ccmgate
Date: 10/27/96 12:30 PM
Gary, I'd put two holes in the lid. First, it's better to have more
venting than too little... You can then cover the flue outlets with
pieces of brick or wool to adjust for the variables of load size,
stack configuration, atmosphere, etc. Second, the handle is in the
center of the lid, and, even though it's a minor inconvenience,
lifting it with one hand with tongs in the other helps me get the
pieces out sooner. I've found that using two burners positioned so as
to create a vortex gives the very best distribution of heat, keeping
flame off the pots, heating more evenly, and much faster. Good luck.
Loran
lrh@deltafaucet.com
----------------------------Original message----------------------------
I am finally getting around to building a garbage can raku kiln. I am
wondering where the flue hole in the lid needs to go. Does it need to go
right in the middle or sould it be placed to one side so that a circular
air flow can be created?
Any help would be greatly appreciated!
Thanks
Gary Ferguson
David Woodin clayart Digest on tue 29 oct 96
I bought a kit years ago for a trash can kiln. A 20 gal can requires a 11
inch in diameter hole in the center of the lid . The burner port is 3 1/2''
by 4'' , cut one inch from bottom of can between the two handles. The burner
is a Venturi burner 85,000 BTU's with Fisher regulator to be used on a
propane tank. It reaches temperature in about 30 minutes. The can is fiber
lined.
Simons, Frank on sat 2 nov 96
Hi Gary--
If you are still looking for info on home built raku kilns the following
may be of some help. There are various ways of building these things.This is
one of the most practical, economical and will produce excellent results.
Find an open top 45 gal drum (50 Stateside) cut off the top portion at 25".
This can be done with a welding torch or by using a metal cutting abrasive
wheel in a Skil saw.If you want handles on it to pack it around, install
them on the shell first. Use round head machines screws or stove bolts. Make
sure the heads are on the inside and the nuts or fasteners on the outside.
This is so that the insulating liner can be removed from the shell easily as
this must be done periodically to replace broken buttons. Use a piece of
rabbit wire 24" by 6 feet long to form around the inside of the drum. (
rabbit wire is the galvanized 3/4" mesh stuff available at most building
supply places)Wire the ends together. Remove this form from the shell and
fit two layers of 1"x24" ceramic fiber around the inside of the rabbit wire
form. The first layer will be about 6' long, second about 5'. Stagger the
joints and secure to the wire backing with bisque buttons about 2 1/2 " in
diameter. Three rows of buttons about 8" apart are usually required. Fasten
the buttons with stainless steel lashing wire. If there are telephone guys
working on cable in your area they usually leave scads of it laying around.
If not tell them you will make them a lifesize raku figurine of Marilyn
Monroe for their lunchroom and they will probably give you some.Cut the wire
into lengths of 8", bend into U shape, thread through buttons and poke thru
fiber and twist ends around some of the mesh. Make sure to bend the twisted
ends back into the fiber with pliers. With any luck at all the insulating
liner should now slide into the shell. An optional 4" semi-circular burner
port can be cut into the bottom of the shell or the whole thing can be
supported on arranged firebrick.The lid is basically the same construction,
cut a cicular piece of rabbit wire 2" larger all around larger than the 2
24" pieces of fiber required for the lid (the drum should be 24" in
diameter)Bend the edges 2" down to protect the edges of the fiber.To give
support to the cover 4 pieces of 1/2 x 1/8" flat bar steel are welded,
bolted or wired together in a square. Attach your wire lid handles to
these.Use buttons to secure fiber to the mesh backing making as many as you
can wire around the flat bar steel crosspieces. Cut the flue opening in the
center. It shound be 4-5" in diameter.
There has been much discussion on weed-burners. I hesitate to call them
that, utility torch would be a better call.The kind most used around here is
the Westorch model 80. It has a rugged cast iron burner assembly, puts out
250,000 to 300,000 BTU at 30 psi.It is made somplace in Alberta.The burner,
10'hose and a Fisher regulator sell for around 85 bucks at the welding
supply places. I have never seen one used for burning weeds, but have
frequently seen road workers using them to melt ashphalt.
Arrangement of kiln shelves is amatter of choice. I find 2 circular half
shelves supported on an open square arrangement of four soft bricks with one
of the openings facing the burner port works OK. The shelves should be about
1" apart with the flat side at right angles to the burner port. A piece of
fire brick in the center helps diffuse the output of the burner.
The first firing takes approx 1 hour 15 min. with subsequent firings of
approx 35 min. A 20 lb propane tank produces 8-10 firings.
Fire the stuff to around 1000 C. if using a pyrometer or till the objects
of art look a transparent orange and sort of wet and shiny. Reduce the kiln
for 3-4 min by decreasing fuel supply slightly and partly cover flue with a
frebrick to produce noiceable backflame at flue opening and burner port. It
is important to get the stuff out of the kiln as quickly as possible into
the reducing cans. Making sure the medium hay, paper, leaves, sawdust,
donkey poo igites before closing the cover. Four or five minutes is usually
sufficient and then out to the spray table where you can enjoy the oohs and
aws of the admiring spectators.
Hope all this makes some sense...... Frank in Penticton
P.S. Dont ever let ceramic fiber get wet, it either disintegrates
immediately or never ever drys out...
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