James F on wed 16 jul 08
I am planning to build a sectional top hat=20
style updraft raku kiln to fire some of my weird slab-built sculptural=20
pieces. My plan is to construct a stationary base to hold an 18"=20
octagonal kiln shelf and a pair of old venturi burners that I have=2C fir=
ing=20
below the shelf=2C and plumbed so that I can fire one or both as needed. =
I=20
will construct a series of three stackable fiber-lined octagonal sections=
=2C=20
perhaps 22" inside diameter by 16" high=2C plus one fiber-lined lid with =
a hole=20
in the top and a small kiln shelf for a damper. The bottom 16" section=20
will be mounted to two uprights using sleeve bearings of some sort=2C and=
will=20
be raised and lowered by a cable winch. The additional sections will sit=
=20
atop the bottom section as needed=2C with the lid sitting at the very top=
. =20
Still following me?
Now the question: Intuitively=2C I feel that=20
when firing little stuff with one 16" section=2C there will be little=20
trouble. I also sense that even with the second section in place (total=
=20
32")=2C the updraft effect will bring enough heat to the top of the sculp=
ture=20
fast enough to compensate for the intense heating at the bottom=2C thereb=
y=20
keeping the sculpture from cracking from differential expansion. I start=
=20
getting really leery with the third section=2C total height 48"=2C firing=
pieces=20
perhaps 42" tall. I'm thinking I would have a really hot bottom=2C a=20
moderately hot top=2C and a cooler middle (the kiln=2C not me)=2C and con=
comitant=20
risk of stress fractures (the pot=2C not me). I'm wondering if anyone ha=
s any thoughts pertaining to this plan off the top of their head=2C or has =
any experience with a tall=2C narrow kiln of any type that they care to rel=
ate. I'm also wondering if I=20
should limit the kiln to just two sections=2C though this would pretty mu=
ch=20
defeat my purpose=2C which is to be able to work bigger than my electric =
kilns=20
will allow. And no=2C I haven't quite figured out the logistic of=20
post-fire reduction of such large pieces=2C but I have a few ideas.
Any thoughts would be appreciated. Thanks.
...James
_________________________________________________________________
Keep your kids safer online with Windows Live Family Safety.
http://www.windowslive.com/family_safety/overview.html?ocid=3DTXT_TAGLM_WL_=
family_safety_072008=
James and Sherron Bowen on wed 16 jul 08
Why not fire with one burner down low and the other up higher. Make a
bracket to hold the one higher up in the kiln. Or fire them both upward so
the flame spirals on an upward path. One thing is for sure with fiber you
can be very flexible in your design
Jim
----- Original Message -----
From: "James F"
To:
Sent: Wednesday, July 16, 2008 2:05 PM
Subject: Thoughts on odd raku kiln?
I am planning to build a sectional top hat
style updraft raku kiln to fire some of my weird slab-built sculptural
pieces. My plan is to construct a stationary base to hold an 18"
octagonal kiln shelf and a pair of old venturi burners that I have, firing
below the shelf, and plumbed so that I can fire one or both as needed. I
will construct a series of three stackable fiber-lined octagonal sections,
perhaps 22" inside diameter by 16" high, plus one fiber-lined lid with a
hole
in the top and a small kiln shelf for a damper. The bottom 16" section
will be mounted to two uprights using sleeve bearings of some sort, and
will
be raised and lowered by a cable winch. The additional sections will sit
atop the bottom section as needed, with the lid sitting at the very top.
Still following me?
Now the question: Intuitively, I feel that
when firing little stuff with one 16" section, there will be little
trouble. I also sense that even with the second section in place (total
32"), the updraft effect will bring enough heat to the top of the
sculpture
fast enough to compensate for the intense heating at the bottom, thereby
keeping the sculpture from cracking from differential expansion. I start
getting really leery with the third section, total height 48", firing
pieces
perhaps 42" tall. I'm thinking I would have a really hot bottom, a
moderately hot top, and a cooler middle (the kiln, not me), and
concomitant
risk of stress fractures (the pot, not me). I'm wondering if anyone has
any thoughts pertaining to this plan off the top of their head, or has any
experience with a tall, narrow kiln of any type that they care to relate.
I'm also wondering if I
should limit the kiln to just two sections, though this would pretty much
defeat my purpose, which is to be able to work bigger than my electric
kilns
will allow. And no, I haven't quite figured out the logistic of
post-fire reduction of such large pieces, but I have a few ideas.
Any thoughts would be appreciated. Thanks.
...James
_________________________________________________________________
Keep your kids safer online with Windows Live Family Safety.
http://www.windowslive.com/family_safety/overview.html?ocid=TXT_TAGLM_WL_family_safety_072008
Tony Ferguson on thu 17 jul 08
James, it will work fine. The beauty of mod is your not stuck with a fixed size.
When you fire, you want to make sure it is even temp--one way to do this is to reduce a bit as you are getting close to temp--this will also slow it down and allow the heat to even out. You can also damper the top a bit with a kiln shelf or piece of fiber board and as it builds heat. If you have to hold it upon getting to temp and notice its not mature, just turn the gas up a bit--experiment and you will figure it out. It's trial and error for every kiln. The diameter of your top hole should be the same as the diameter of your in hole. Make sure to raise your work up on wads or chipped pieces of kiln shelves so the heat can circulate underneath the work.
Tony Ferguson
James F wrote: I am planning to build a sectional top hat
style updraft raku kiln to fire some of my weird slab-built sculptural
pieces. My plan is to construct a stationary base to hold an 18"
octagonal kiln shelf and a pair of old venturi burners that I have, firing
below the shelf, and plumbed so that I can fire one or both as needed. I
will construct a series of three stackable fiber-lined octagonal sections,
perhaps 22" inside diameter by 16" high, plus one fiber-lined lid with a hole
in the top and a small kiln shelf for a damper. The bottom 16" section
will be mounted to two uprights using sleeve bearings of some sort, and will
be raised and lowered by a cable winch. The additional sections will sit
atop the bottom section as needed, with the lid sitting at the very top.
Still following me?
Now the question: Intuitively, I feel that
when firing little stuff with one 16" section, there will be little
trouble. I also sense that even with the second section in place (total
32"), the updraft effect will bring enough heat to the top of the sculpture
fast enough to compensate for the intense heating at the bottom, thereby
keeping the sculpture from cracking from differential expansion. I start
getting really leery with the third section, total height 48", firing pieces
perhaps 42" tall. I'm thinking I would have a really hot bottom, a
moderately hot top, and a cooler middle (the kiln, not me), and concomitant
risk of stress fractures (the pot, not me). I'm wondering if anyone has any thoughts pertaining to this plan off the top of their head, or has any experience with a tall, narrow kiln of any type that they care to relate. I'm also wondering if I
should limit the kiln to just two sections, though this would pretty much
defeat my purpose, which is to be able to work bigger than my electric kilns
will allow. And no, I haven't quite figured out the logistic of
post-fire reduction of such large pieces, but I have a few ideas.
Any thoughts would be appreciated. Thanks.
...James
_________________________________________________________________
Keep your kids safer online with Windows Live Family Safety.
http://www.windowslive.com/family_safety/overview.html?ocid=TXT_TAGLM_WL_family_safety_072008
Tony Ferguson
315 N. Lake Ave. Apt 312
Duluth, MN 55806
...where the sky meets the lake...
Artist, Educator, Photographer, Film Maker, Web Meister
fergyart@yahoo.com
(218) 727-6339
http://www.tonyferguson.net
James F on thu 17 jul 08
Jim..
I thought about this=2C but was concerned that any direct flame impingement=
would cause my strange pots to pull themselves apart. I considered a muff=
le design to combat this=2C but things got "un-simple" very quickly. Do yo=
u not feel that flame impingement would be an issue? Thanks.
...James
>=20
> Why not fire with one burner down low and the other up higher. Make a
> bracket to hold the one higher up in the kiln. Or fire them both upward =
so
> the flame spirals on an upward path. One thing is for sure with fiber you
> can be very flexible in your design
> Jim
>=20
> ----- Original Message -----
> From: "James F"
> To:
> Sent: Wednesday=2C July 16=2C 2008 2:05 PM
> Subject: Thoughts on odd raku kiln?
>=20
>=20
> I am planning to build a sectional top hat
> style updraft raku kiln=20
_________________________________________________________________
Keep your kids safer online with Windows Live Family Safety.
http://www.windowslive.com/family_safety/overview.html?ocid=3DTXT_TAGLM_WL_=
family_safety_072008=
Lynn Paccassi-Berry on thu 17 jul 08
Hi James=2C
I don't think you'd have a problem with the kiln heating up and having a re=
latively even temp throughout. I would be leery of putting a second burner =
higher up in the kiln as Jim suggested (sorry) but the one thing you don't =
want is flame directly on your piece. My raku kiln is about 37" inches high=
and I've not had a problem with the whole thing heating up and the differe=
nce between 37 and 48 is not enough to make that much of a difference. Gran=
ted=2C mine is soft brick and it has 3 burners that do face upwards. The pe=
rson you would really get good advice from would be Steven Branfman. He's a=
t sbranfpots@aol.com or maybe pottersshop@aol.com.=20
Good luck and let us know how it works out.
Lynn
+++++++++++++++++++++++++++++++++++++++++++++++=20
It hath been revealed and is now repeated that=20
the true worth of artists and craftsmen should
be appreciated=2C for they advance the affairs
of mankind. *** 'Abdu'l-Baha ***
+++++++++++++++++++++++++++++++++++++++++++++++
> Date: Wed=2C 16 Jul 2008 17:29:45 -0600
> From: jbowen43@PRAIRIENETWORKS.COM
> Subject: Re: Thoughts on odd raku kiln?
> To: CLAYART@LSV.CERAMICS.ORG
>
> Why not fire with one burner down low and the other up higher. Make a
> bracket to hold the one higher up in the kiln. Or fire them both upward s=
o
> the flame spirals on an upward path. One thing is for sure with fiber you
> can be very flexible in your design
> Jim
>
> ----- Original Message -----
> From: "James F"=20
> To:=20
> Sent: Wednesday=2C July 16=2C 2008 2:05 PM
> Subject: Thoughts on odd raku kiln?
>
>
> I am planning to build a sectional top hat
> style updraft raku kiln to fire some of my weird slab-built sculptural
> pieces. My plan is to construct a stationary base to hold an 18"
> octagonal kiln shelf and a pair of old venturi burners that I have=2C fir=
ing
> below the shelf=2C and plumbed so that I can fire one or both as needed. =
I
> will construct a series of three stackable fiber-lined octagonal sections=
=2C
> perhaps 22" inside diameter by 16" high=2C plus one fiber-lined lid with =
a
> hole
> in the top and a small kiln shelf for a damper. The bottom 16" section
> will be mounted to two uprights using sleeve bearings of some sort=2C and
> will
> be raised and lowered by a cable winch. The additional sections will sit
> atop the bottom section as needed=2C with the lid sitting at the very top=
.
> Still following me?
>
> Now the question: Intuitively=2C I feel that
> when firing little stuff with one 16" section=2C there will be little
> trouble. I also sense that even with the second section in place (total
> 32")=2C the updraft effect will bring enough heat to the top of the
> sculpture
> fast enough to compensate for the intense heating at the bottom=2C thereb=
y
> keeping the sculpture from cracking from differential expansion. I start
> getting really leery with the third section=2C total height 48"=2C firing
> pieces
> perhaps 42" tall. I'm thinking I would have a really hot bottom=2C a
> moderately hot top=2C and a cooler middle (the kiln=2C not me)=2C and
> concomitant
> risk of stress fractures (the pot=2C not me). I'm wondering if anyone has
> any thoughts pertaining to this plan off the top of their head=2C or has =
any
> experience with a tall=2C narrow kiln of any type that they care to relat=
e.
> I'm also wondering if I
> should limit the kiln to just two sections=2C though this would pretty mu=
ch
> defeat my purpose=2C which is to be able to work bigger than my electric
> kilns
> will allow. And no=2C I haven't quite figured out the logistic of
> post-fire reduction of such large pieces=2C but I have a few ideas.
>
> Any thoughts would be appreciated. Thanks.
>
> ...James
>
> _________________________________________________________________
> Keep your kids safer online with Windows Live Family Safety.
> http://www.windowslive.com/family_safety/overview.html?ocid=3DTXT_TAGLM_W=
L_family_safety_072008
_________________________________________________________________
Connect to the next generation of MSN Messenger=A0
http://imagine-msn.com/messenger/launch80/default.aspx?locale=3Den-us&sourc=
e=3Dwlmailtagline=
Tony Ferguson on thu 17 jul 08
Flame impingement wouldn't be an issue if you prop the shelf on 9" bricks or slightly higher and have your entry hole underneath it. You can have your burner shoot into the chamber beneath the shelf and strategically place a deflection brick underneath the shelf so it angles to the right.
Tony Ferguson
James F wrote: Jim..
I thought about this, but was concerned that any direct flame impingement would cause my strange pots to pull themselves apart. I considered a muffle design to combat this, but things got "un-simple" very quickly. Do you not feel that flame impingement would be an issue? Thanks.
...James
>
> Why not fire with one burner down low and the other up higher. Make a
> bracket to hold the one higher up in the kiln. Or fire them both upward so
> the flame spirals on an upward path. One thing is for sure with fiber you
> can be very flexible in your design
> Jim
>
> ----- Original Message -----
> From: "James F"
> To:
> Sent: Wednesday, July 16, 2008 2:05 PM
> Subject: Thoughts on odd raku kiln?
>
>
> I am planning to build a sectional top hat
> style updraft raku kiln
_________________________________________________________________
Keep your kids safer online with Windows Live Family Safety.
http://www.windowslive.com/family_safety/overview.html?ocid=TXT_TAGLM_WL_family_safety_072008
Tony Ferguson
315 N. Lake Ave. Apt 312
Duluth, MN 55806
...where the sky meets the lake...
Artist, Educator, Photographer, Film Maker, Web Meister
fergyart@yahoo.com
(218) 727-6339
http://www.tonyferguson.net
| |
|
