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raku kiln question

updated fri 3 oct 03

 

Mary Hays on thu 1 may 97

I've been firing with a ceramic fiber kiln. I started out using a weed
burner, but upgraded to a venturi burner. Since the change in burners, I now
have black soot covering the outside of my kiln. I looked in 2 books, Raku by
Steve Branfman & Raku Pottery by Robert Piepenburg. The only thing I can come
close to figuring is the opening on top of my kiln needs to be larger. But if
it fired fine before, why would it change with a different burner. (I use
propane for fuel)
Sometimes the frustrating part is I am self taught/ so I devour books to find
the answers to my questions, but getting different answers depending on which
book I read.
I will certainly appreciate any help and info.
Mary Hays
Blue Springs, MO
jhaysbsmo@aol.com

WardBurner@aol.com on fri 2 may 97

Mary,

The weed burner you were using most likely did not have a spin down plate
(air shutter) so you may not be used to this feature. The burner you bought
from me has an air shutter. Spin this open all the way so the burner can get
enough air. Other folks, like Mary, who have bought products from us, please
don't hesitate to call if you have questions. Answers come with the
products....

Marc Ward
Ward Burner Systems
PO Box 333
Dandridge, TN 37725
USA
423.397.2914 voice
423.397.1253 fax
wardburner@aol.com

Kathy Darnell on fri 2 may 97

Mary Hays wrote:
>
> ----------------------------Original message----------------------------
> I've been firing with a ceramic fiber kiln. I started out using a weed
> burner, but upgraded to a venturi burner. Since the change in burners, I now
> have black soot covering the outside of my kiln. I looked in 2 books, Raku by
> Steve Branfman & Raku Pottery by Robert Piepenburg. The only thing I can come
> close to figuring is the opening on top of my kiln needs to be larger. But if
> it fired fine before, why would it change with a different burner. (I use
> propane for fuel)
> Sometimes the frustrating part is I am self taught/ so I devour books to find
> the answers to my questions, but getting different answers depending on which
> book I read.
> I will certainly appreciate any help and info.
> Mary Hays
> Blue Springs, MO
> jhaysbsmo@aol.com
You probably have a natural gas orifice instead of a propane orifice in
the venturi burner that you are now using. A friend of mine ordered a
venturi that didn't work properly. She called the company that sold her
the burner and explained again that it would be used with propane. They
mailed her another orifice just like the one she was tryin to use.
Then, she took the burner to a local propane dealer who solved her
problem. Propane orifices are snaller than natural gas orifices. Nuf
said!
J.E. "Chic" Darnell

stevemills on fri 2 may 97

In message <970430205603_-1968845550@emout18.mail.aol.com>, Mary Hays
writes
>----------------------------Original message----------------------------
>I've been firing with a ceramic fiber kiln. I started out using a weed
>burner, but upgraded to a venturi burner. Since the change in burners, I now
>have black soot covering the outside of my kiln. I looked in 2 books, Raku by
>Steve Branfman & Raku Pottery by Robert Piepenburg. The only thing I can come
>close to figuring is the opening on top of my kiln needs to be larger. But if
>it fired fine before, why would it change with a different burner. (I use
>propane for fuel)
>Sometimes the frustrating part is I am self taught/ so I devour books to find
>the answers to my questions, but getting different answers depending on which
>book I read.
>I will certainly appreciate any help and info.
>Mary Hays
>Blue Springs, MO
>jhaysbsmo@aol.com
Dear Mary
You have far too much fuel going in and/or too little air. Turn the
burner RIGHT back and work on the smallest setting you can consistant
with a rise in temperature.
(Now who was it who said "more equals less"?)
Steve
--
Steve Mills
@Bath Potters Supplies
Dorset Close
Bath
BA2 3RF
UK
Tel:(44) (0)1225 337046
Fax:(44) (0)1225 462712

Tracy Dotson on sat 3 may 97

mary..........from the information it sounds like the orfice is too large.
you may have a burner set for natural gas. Check with your propane co to
have the orfice checked. good luck tracy

BobWicks@aol.com on sun 4 may 97

Mary:

Your problem with the raku firing is the gas/air ratio. When you have soot
all over, this means that you do not have enough air or you have too much gas
for the air that is available. Try everything you can to adjust the air
intake. You might pull th/e burner back out of the burner port a little and
notice the difference. When you have the gas/air mixture correct your glazes
will fuse in just a few minutes.

Good luck.

Bob

Susan Goldstein on wed 2 jun 99

I fired my raku kiln last week and could not get the temperature to go above
1500 degrees. I can not figure out what is causing my problem. The kiln is
a metal cage lined with fiber with a front loading door. The pressure gage
adjacent to the propane tanks did not indicate any problem and all else was
the same as in the past, when I fire up to 1800 degrees without any problem
within thirty minutes. The last time I used my kiln, about a month ago, I
left it out to cool during the night and it rained. Could this have anything
to do with this problem? What could?

Thanks for any information.

Susan

Russ & Wendy Keeler on thu 3 jun 99

Susan,

Last summer I had the exact situation occur. I mentioned it to the R&D
Manager at the company I work for. He said that the presence of high
moisture in the bricks when heated was filling the atmosphere with extra
Hydrogen and Oxygen. Which creates an inefficient flame, the result is
similar to a reduction atmosphere stalling. He recommended dropping the
temperature and steaming out the moisture. It worked, but seemed like a
waste of propane. Good luck.

Wendy

----------------------------Original message----------------------------
I fired my raku kiln last week and could not get the temperature to go
above
1500 degrees. I can not figure out what is causing my problem. The kiln is
a metal cage lined with fiber with a front loading door. The pressure gage
adjacent to the propane tanks did not indicate any problem and all else was
the same as in the past, when I fire up to 1800 degrees without any problem
within thirty minutes. The last time I used my kiln, about a month ago, I
left it out to cool during the night and it rained. Could this have
anything
to do with this problem? What could?

Thanks for any information.

Susan

Carole Fox on fri 25 oct 02


For a long time now I have been trying to troubleshoot my firing problems
with my raku kiln. I am able to fire my loads, but I think I am wasting a
lot of propane in the process. I made this kiln with a soft brick bottom, a
Ward venturi burner and a fiber bonnet. My problem is I can't get the flame
to come up above the shelf. Even if I turn the gas all the way up. I thought
the shelf was too big- smaller shelf did not help. I thought the flue was
too big- partially covering the flue hole did not help. I thought the burner
port was too big- nope. I thought the pressure was set too high- turned it
back to about 8 and still no luck. I used to be able to get the flame up if
I turned down the air control thing-a-ma-jig on the burner and put the kiln
into reduction- but that is wasteful too, eh?

I always thought that the burner sounded too loud- too airy. I don't know if
that means anything.

When I learned to raku at the local art studio, I would judge my firings by
flame- I started with flame just licking the edge of the shelf, then halfway
up the bonnet and finish off with a small flame peeping out the top-
sometimes a medium flame out the flue for certain glazes.

Now I just watch my pots through the flue hole and turn up the gas at
sintering stage, then as the glaze begins to get that wet look. But with the
gas at full tilt, the burner sounds so loud and though the kiln heats up
enough to fire the glaze- there is no visible flame.

I am afraid this has something to do with orifice size - which I know
nothing about. I made this kiln exactly like the one at the local art studio
except that I doubled the fiber in the bonnet and made the outer cage a
little bigger to accommodate that. I admit that I am poorly trained as far
as firing goes and I apologize. But is there anything else to check other
than orifice size? And how does one determine how to change the orifice
size?


Carole Fox-in Elkton, MD
- and I really don't mind that my studio phone has clay on it, but if
anybody can tell me how to blow my nose without having to wash and dry my
hands first, I would be much obliged!
cfox@dca.net

Mike Gordon on fri 25 oct 02


Carol,
I wouldn't worry too much about the sound of the kiln, nor where the
flame is in relation to the shelf. If your glazes are turning out to
your liking, then great! I sometimes pull my burner out of the port a
little at the end to suck in a little more air. I can see the flame and
it's blue. I think the volume of your kiln mught be different than the
one you copied and if that is the case...... you won't see any flema out
of the top. As far as blowing your nose with clay on your hands, just
clean your thumb, place it over a nostrel and blow! Mike Gordon

Laurie Kneppel on thu 2 oct 03


I get some very interesting questions from people who write via my
website and to be honest I couldn't really say for 100 percent certain
that you can't do this, so I thought I would run it past the group and
see what you all thought. Maybe somebody has even tried it!

A writer asks if it is possible to do raku in a wood-fired kiln. They
have an old brick barbecue that they want to turn into a wood-fired
kiln. Now I do not know what the barbecue looks like or its dimensions
or anything, but say it was possible to convert it into a kiln, can you
do raku this way?

Keep in mind that I do not know anything more than what I have read
about wood firing because I live in the city.

Laurie
Sacramento, CA
http://rockyraku.com

Paul Herman on thu 2 oct 03


Hi Laurie,

Greetings from over on the other side of the Sierra.

Sure you could fire your raku pots with wood. I've never done it, but
have seen an article on the subject. I think it was about a Potter named
Nesrin Durin (sp?). Sorry, I can't remember where.

As for the BBQ/Kiln conversion, well I don't know. Nothing is
impossible. I assume they want to fire to ^06 or so. Portland Cement
based brick mortar won't hold up at that temperature.

Good firings,

Paul Herman
Great Basin Pottery
423-725 Scott Road
Doyle, California 96109 US
potter@psln.com

----------
>From: Laurie Kneppel

> A writer asks if it is possible to do raku in a wood-fired kiln. They
> have an old brick barbecue that they want to turn into a wood-fired
> kiln. Now I do not know what the barbecue looks like or its dimensions
> or anything, but say it was possible to convert it into a kiln, can you
> do raku this way?
>
> Keep in mind that I do not know anything more than what I have read
> about wood firing because I live in the city.

Les Haworth on thu 2 oct 03


Laurie, You can do Raku in what ever kiln you want. Wood, Coal, Gas, Any
combustible...Don't let anyone tell you different. As a matter of fact you
can do Raku in a shallow pit, or at the beach, or even at the shopping mall.
I know because I've done it, in all three of these places and with a great
deal of success. My mentor Charlene Felos used to take us (Students) to the
local beach each semester and do a Raku pit firing. Not many teachers in So.
California do that, but it taught me that you could do Raku anywhere you
wanted to. Just be sure to get the correct permissions before you start....
I love to Raku. So much so, that I'm doing my second workshop with a local
private school this fall. Very exciting for me I might add. Anyway just
enjoy yourself and be safe.



Lester R. Haworth III
Sales and Technical Support
Laguna Clay Co.
14400 Lomitas ave
City of Industry, CA 91746
(626)330-0631 ext. 229
les@lagunaclay.com
www.lagunaclay.com

"I never collaborated with him or anyone else, ever. I mean, you don't
collaborate on your art with somebody. That's your own personal and only
thing that you have that's yours, period." ~ Peter Voulkos

-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of Laurie
Kneppel
Sent: Thursday, October 02, 2003 1:47 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Raku Kiln Question


I get some very interesting questions from people who write via my
website and to be honest I couldn't really say for 100 percent certain
that you can't do this, so I thought I would run it past the group and
see what you all thought. Maybe somebody has even tried it!

A writer asks if it is possible to do raku in a wood-fired kiln. They
have an old brick barbecue that they want to turn into a wood-fired
kiln. Now I do not know what the barbecue looks like or its dimensions
or anything, but say it was possible to convert it into a kiln, can you
do raku this way?

Keep in mind that I do not know anything more than what I have read
about wood firing because I live in the city.

Laurie
Sacramento, CA
http://rockyraku.com

____________________________________________________________________________
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Tony Ferguson on thu 2 oct 03


Laurie,

You can just about convert anything into a raku kiln if you understand how
fire works, how to contain it properly, and utilize a little ingenuity. The
original raku kilns were all wood fired. The brick barby will need to be
properly insulated if he wants to get any number of firings out of it--it
will be the mortar that fails first or perhaps the brick, if it was low
grade (there could be some interesting popouts or melt downs--can you tell I
found out?). If he thinks it was built with some type of fire brick, find
a chunk and fire it 200 degrees above the temp he plans to fire his raku to.
I have not used ITC, but I suppose applying that might be an option. Brick
or fiber lined will do it.


Thank you.

Tony Ferguson
On Lake Superior, where the sky meets the Lake

Custom & Manufactured Kiln Design
Stoneware, Porcelain, Raku and more
by Coleman, Ferguson, Winchester...
http://www.aquariusartgallery.com
218-727-6339
315 N. Lake Ave
Apt 312
Duluth, MN 55806


----- Original Message -----
From: "Laurie Kneppel"
To:
Sent: Thursday, October 02, 2003 3:46 PM
Subject: Raku Kiln Question


> I get some very interesting questions from people who write via my
> website and to be honest I couldn't really say for 100 percent certain
> that you can't do this, so I thought I would run it past the group and
> see what you all thought. Maybe somebody has even tried it!
>
> A writer asks if it is possible to do raku in a wood-fired kiln. They
> have an old brick barbecue that they want to turn into a wood-fired
> kiln. Now I do not know what the barbecue looks like or its dimensions
> or anything, but say it was possible to convert it into a kiln, can you
> do raku this way?
>
> Keep in mind that I do not know anything more than what I have read
> about wood firing because I live in the city.
>
> Laurie
> Sacramento, CA
> http://rockyraku.com
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>

steve harrison on fri 3 oct 03


Hi Laurie,
Yes! raku can certainly be done in a wood fired kiln. (That is how it
all started.) We have a couple of them here at our workshop.
Whether your informant can convert his/her BBQ to a kiln is a different
question. I'd say probably not. Pull the whole thing down and start
from scratch with a reliable kiln plan and suitable materials.
Best wishes
Steve Harrison

Hot & Sticky Pty Ltd
5 Railway Pde
Balmoral Village
NSW 2571
Australia

http://ian.currie.to/sh/Steve_Harrisons_books.html
>
> A writer asks if it is possible to do raku in a wood-fired kiln. They
> have an old brick barbecue that they want to turn into a wood-fired
> kiln. Now I do not know what the barbecue looks like or its dimensions
> or anything, but say it was possible to convert it into a kiln, can you
> do raku this way?
>

Brian on fri 3 oct 03


On 2/10/03,Laurie wrote...
>A writer asks if it is possible to do raku in a wood-fired kiln.


this easily built hard brick kiln structure with no shelves is ideal
for raku firings
A 100+ bricks and some dry wood and you are away........!!
just pile the pots in and lift out when ready.

http://www.gartside.info/woodkilnintro.htm

for raku ideas see

http://www.gartside.info/rakupageone.htm

Brian