Teri Lee on wed 5 jul 06
Hello,
=20
I've just built a raku kiln out of the shell of an old electric Paragon
kiln and have been having problems with a big hotspot in the back of the
kiln-across from the burner, which comes in at a 90-degree angle on the
side of the kiln. I tried cutting the stream of fire by putting a post
in front of the burner entry but that doesn't seem to be doing the
trick. I'm thinking of putting two bricks in a "V" formation where the
post is, and maybe another brick in the back. In James Watkins and Paul
Wandless book, "Alternative Firing Techniques," they recommend building
a ring of small baffles just below the kiln shelf, but their raku kiln
is larger than mine, don't know if I should go that route.
=20
My kiln is about 16" in diameter and 22" deep. Any and all suggestions
are deeply appreciated!
=20
=20
Thanks,
Teri Lee
=20
Snail Scott on wed 5 jul 06
At 03:47 PM 7/5/2006 -0700, you wrote:
>...
>I've just built a raku kiln out of the shell of an old electric Paragon
>kiln and have been having problems with a big hotspot in the back of the
>kiln-across from the burner, which comes in at a 90-degree angle on the
>side of the kiln...
Try aiming the burner at an angle instead of=20
90=BA, sort of tangent to the wall of the kiln,=20
so the flame will circle around in a spiral=20
instead of smacking flat into the opposite=20
side.
-Snail
John Post on wed 5 jul 06
You could try 3 firebricks as shelf supports. Leave an opening for the
flame to enter and then space the 3 bricks around the sides. One could
be in the back where the flame hits. I don't know how much height you
need above your shelf but if you don't need all of it, this may work.
John Post
Sterling Heights, Michigan
>I've just built a raku kiln out of the shell of an old electric Paragon
>kiln and have been having problems with a big hotspot in the back of the
>kiln-across from the burner,
>
>
>
Marcia Selsor on wed 5 jul 06
Maybe you should cut back on the burner. Give some breathing room
around the shelf.
Maybe you are using too high of a setting on your burner. The v idea
is good. I know the \
baffles you mention from the Alternative firing book, but I agree
your kiln is too small for those..
Marcia
Marcia Selsor
http://marciaselsor.com
Taylor Hendrix on thu 6 jul 06
Old square paragon, old round paragon?
I've helped convert an old paragon square and we had no hot back.
Soft brick flame splitter right up under the shelf pretty close to
port. Plenty of room around shelf. Slow but steady, right Barb?
Taylor in Rockport, TX
On 7/5/06, Marcia Selsor wrote:
> Maybe you should cut back on the burner. Give some breathing room
> around the shelf.
> Maybe you are using too high of a setting on your burner. The v idea
> is good. I know the \
> baffles you mention from the Alternative firing book, but I agree
> your kiln is too small for those..
> Marcia
Richard White on thu 6 jul 06
I use several soft IFB bricks cut in half as shelf supports. One of them is
positioned directly in front of the burner opening and set on a diagonal
with a corner pointing directly into the path of the flame. The difference
between what I am doing and your use of a regular post is that the half
brick is wide enough to divide the flame in half and divert the flows of
the burning gas to each side, while your smaller post merely causes some
turbulence as the flame passes around it on its way straight to the back.
dw
William & Susan Schran User on thu 6 jul 06
On 7/5/06 10:43 PM, "Marcia Selsor" wrote:
> Maybe you should cut back on the burner. Give some breathing room
> around the shelf.
I agree with Marcia.
One of my students set up a raku kiln and complained she couldn't get to
temperature and was using up a small propane tank of gas for just a couple
firings. She had no pressure gauge. Told her to get a regulator/pressure
gauge, but before that, had her come listen to the burner on our kiln at
different pressure settings and get an idea of what sound/how loud the
various pressure settings were.
I've found most of the time when folks come to me with a small gas fired
kiln that won't get to temperature, stalls or has hot spots, that simply
turning down the pressure solves the problem.
So, keep the target/flame-splitter brick in place, make sure the burner is
positioned outside of the burner opening with at least a 1" gap for
secondary air and turn down the pressure. You probably don't have to go over
1 lb of pressure.
Let us know if this helps in resolving the hot spot.
-- William "Bill" Schran
Fredericksburg, Virginia
wschran@cox.net
wschran@nvcc.edu
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