Doug Gray on wed 4 jun 97
I was just wondering if it matters what size sand you use in a raku
clay body if the recipe calls for it. I understand that sand helps to
keep the clay body open (therefore helping it with thermal shock), but
will even the really fine stuff work or do I need big particle sand
like play ground sand?
Doug Gray
Alpine, TX
dgray@sul-ross-1.sulross.edu
Dennis Mummert on wed 31 jan 01
I'm also of mixed feelings about the customary water dousing. Have done it,
and not done it. OTOH, I have watched the piece cool and change colors
AFTER the glaze hardened.
-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.CERAMICS.ORG]On
Behalf Of Randall Moody
Sent: Wednesday, January 31, 2001 4:28 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Raku question
While watching a recent raku firing I realized that I have never had a good
explanation as to why people toss their pots in water. One person I asked
said it was to 'fix' the glaze, but that really doesn't make any sense when
you consider that the glaze sets once it is cooler than it's melting point.
Once the glaze gets, say 100 degrees, below the melting point it is not as
if the glaze is going to continue to flow. I understand that spraying a
crackle glaze helps promote the crackle but other than that why subject the
pot to yet another thermal shock?
I am open to any suggestions (other than "That's just the way it's done.")
Randall
____________________________________________________________________________
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Larry Phillips on wed 31 jan 01
Randall Moody wrote:
>
> One person I asked said it was to 'fix' the glaze, but that really
> doesn't make any sense when you consider that the glaze sets once it
> is cooler than it's melting point. Once the glaze gets, say 100
> degrees, below the melting point it is not as if the glaze is going
> to continue to flow.
The glaze may be solid, but it's still open to acquiring oxygen from the
air. The idea of the reducing atmosphere is to draw oxygen out of the
glaze to promote different colours in glazes, and if you just pull a hot
pot and let it sit in open air, the glaze materials may still oxidize.
That having been said, I prefer not to use water if I have the luxury of
allowing the pot to cool in the reduction bin.
--
If you're not living on the edge, you're taking up too much room!
http://cr347197-a.surrey1.bc.wave.home.com/larry/
Milton Markey on wed 31 jan 01
Hi Randall, and other fellow Raku'ers:
Some folks dip thier pots into water to loosen up the soot inside the pot.
It's probably easier for the soot to loosen up when it's still hot. I don't
recommend placing a "just-fired" pot into water, though, or cracks and
thermal shockies might occur.
Milton NakedClay@AOL.COM
Still creating despite the chill of the night. But the moon, stars, and
planets in the sky make thriving in the Mojave worthwhile.
Randall Moody on wed 31 jan 01
While watching a recent raku firing I realized that I have never had a =
good explanation as to why people toss their pots in water. One person I =
asked said it was to 'fix' the glaze, but that really doesn't make any =
sense when you consider that the glaze sets once it is cooler than it's =
melting point. Once the glaze gets, say 100 degrees, below the melting =
point it is not as if the glaze is going to continue to flow. I =
understand that spraying a crackle glaze helps promote the crackle but =
other than that why subject the pot to yet another thermal shock?
I am open to any suggestions (other than "That's just the way it's =
done.")
Randall
Kim Peterson on thu 1 feb 01
Randall,
This is what I've been told.
While the glaze won't flow any more, the colors will continue to change.
ususally from coppers to greens. Somewhere in between there will be a whole
bunch of reds, yellows, purples... When you find a good combination of
colors, put it into the water to fex them. The colors will lock into the
colors that are in the glaze. Eventually, the colors will "tarnish" or turn
to a greenish tint, but until then... enjoy the beautful peices.
Kim
>From: Randall Moody Reply-To: Ceramic Arts Discussion List To:
>CLAYART@LSV.CERAMICS.ORG Subject: Raku question Date: Wed, 31 Jan 2001
>16:27:38 -0500
>
>While watching a recent raku firing I realized that I have never had a good
>explanation as to why people toss their pots in water. One person I asked
>said it was to 'fix' the glaze, but that really doesn't make any sense when
>you consider that the glaze sets once it is cooler than it's melting point.
>Once the glaze gets, say 100 degrees, below the melting point it is not as
>if the glaze is going to continue to flow. I understand that spraying a
>crackle glaze helps promote the crackle but other than that why subject the
>pot to yet another thermal shock? I am open to any suggestions (other than
>"That's just the way it's done.") Randall
>
>______________________________________________________________________________
>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.
_________________________________________________________________
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Marcia Selsor on thu 1 feb 01
I guess they want to cool it faster, period. I don't do it because it
could crack my big pieces. I agree with you. It may just be "because you can!"
Marcia
Randall Moody wrote:
>
> While watching a recent raku firing I realized that I have never had a good explanation as to why people toss their pots in water. One person I asked said it was to 'fix' the glaze, but that really doesn't make any sense when you consider that the glaze sets once it is cooler than it's melting point. Once the glaze gets, say 100 degrees, below the melting point it is not as if the glaze is going to continue to flow. I understand that spraying a crackle glaze helps promote the crackle but other than that why subject the pot to yet another thermal shock?
> I am open to any suggestions (other than "That's just the way it's done.")
> Randall
>
> ______________________________________________________________________________
> 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.
--
Marcia Selsor
selsor@imt.net
http://www.imt.net/~mjbmls
http://www.imt.net/~mjbmls/Tuscany2001.html
Carole Fox on thu 1 feb 01
Randall Moody wrote:
While watching a recent raku firing I realized that I have never had a =
=3D
good explanation as to why people toss their pots in water. One person I =
=3D
asked said it was to 'fix' the glaze, but that really doesn't make any =
=3D
sense when you consider that the glaze sets once it is cooler than it's =
=3D
melting point. Once the glaze gets, say 100 degrees, below the melting =
=3D
point it is not as if the glaze is going to continue to flow. I =3D
understand that spraying a crackle glaze helps promote the crackle but =
=3D
other than that why subject the pot to yet another thermal shock?
I am open to any suggestions (other than "That's just the way it's =3D
done.")
The reason that some people put their pots in water is to prevent the =
glaze from reoxidizing further. They're not fixing the glaze to the pot; =
they are "fixing" the color in the glaze.
I, personally do not like to put my pots in water -even to clean them. I =
have heard that it weakens the pot. It makes the pot practically =
impossible to refire. Also, I spray my pieces with acrylic and need to =
be sure that they are dry before spraying.
If you have a tightly sealed reduction chamber that is not too big for =
the piece you are rakuing, reoxidation shouldn't be a problem.
Regards,
Carole Fox -in Elkton, MD
Scott North on thu 1 feb 01
Hello Randall,
There are probably as many styles of performing a raku
firing/reduction as there are people doing the performance. In my opinion,
if you are firing a clear or white crackle glaze, there is no purpose in a
fast cool with water. The glaze is not going to change upon cooling and
the black in the crackles and bare clay is carbon stain and will probably
not burn off with a slower cool. I never use a water quench with this
surface.
On the other hand, if your glaze contains metals that change
appearance with the atmosphere they are subjected to (copper, iron, etc),
then a fast water cooling may be beneficial. Some of my larger thrown
bottle forms ( 18 to 24 inch round forms) are fired with a copper saturated
glaze, pulled from the kiln and quickly reduced with smoke, and then within
30 seconds of removal from the kiln are doused with a bucket of water and
sprayed with a hose to stop the copper from reoxidizing past a point that
suits my aesthetic fancy. This is my preference for the effects that I
want. It is also very exciting to perform (lots of steam and noise and
fast action fun). Can't remember breaking a pot except through my own
recklessness. Proper clay is a must (I usually use Soldate 60 from
Laguna). This fast water cooling gives a whole different look than leaving
the pot in a reduction chamber to cool slowly. But this is only one way to
do it. Many people are making beautiful copper raku pieces with many
different techniques.
My advice is to learn the chemistry and physics of whatever raku
processes you want to do, and then use your creativity to make up several
different techniques using these basic principles, then try them all
several times. Words only go so far in explaining the magic.
Good luck, Scott
Scott C. North
Geology Department
Humboldt State University
Arcata, CA 95521
phone: (707) 826-3210
FAX: (707) 826-5241
Jocelyn McAuley on thu 1 feb 01
Hi Randall,
I've recently been told that the water quenching step helps fix the
black on bare clay from the post fire reduction. This is something I've
always ment to experiment with... funny how the simplest things can escape
us years into the process!
Jocelyn
--
Jocelyn McAuley ><<'> jocie@worlddomination.net
Stephani Stephenson on fri 2 feb 01
My thought on why someone would quench a raku piece
is that immersing the piece in water prevents air from contacting the
piece while it
is still at a high, reeactive temperature.
So further oxidation is halted, at least while the piece is in the
water.
if it is taken back out while hot it must still reoxidize some.
So water quenching seems like a sort of carbonless reduction method
Some potters may have a specific reason if they use it, perhaps they
use it with a particular glaze
I think the other reason is the drama ,the sizzling, the steam!
or either force of habit
or not wanting to wait to see results!
so maybe it is more about human nature than ceramic science?
quien sabe?
Stephani Stephenson
Leucadia CA
mudmistress@earthlink.net
Sandy Tesar on fri 2 feb 01
I spray my work with water, pour water over it in a sheet, even way , and
occassionally dunk it as needed. The reason I do this is that I use a
combination of luster, coppermatt, commercial glazes and underglazes on a
piece. When the work comes out of the reduction chamber, the colors
reintroduced to oxygen, begin to change. I rapid cool the areas I want to
maintain colors in as they ripple past. The lusters need speedy cooling,
the coppermat varies as to the results I want on various pieces and the
underglaze/glazes have premium crackle time at certain temperatures. The
trick, of course, is to not create your OWN disaster with too uneven
cooling.
Hope this helps some.
Sandy T.
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Rebecca Gregory on sun 4 feb 01
When I did raku firing in college, I plunged my raku pieces in water. Mind
you, I did like the sizzle and steam coming off the water as the hot pieces
were cooling down in their water bath, BUT I did notice that I got brighter
oranges, reds and yellows when I dumped the pieces into water than when I
let the pieces stay in the reduction cans. I got into the habit of watching
the colors come forth, and I would experiment with dipping half way, on one
side first then the other, then the whole thing. I really like the results
I had gotten. I haven't done raku firing a couple of years...So, that was
the reason I dumped my pots in water.
Becky Gregory
Nashville, TN USA
----Original Message Follows----
From: Stephani Stephenson
I think the other reason is the drama ,the sizzling, the steam!
or either force of habit
or not wanting to wait to see results!
so maybe it is more about human nature than ceramic science?
_________________________________________________________________
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WHew536674@CS.COM on mon 5 feb 01
For the long neck bottles, you might try spraying gently with a hose. This
way you won't have to worry about explosions or smoke
Joyce A
dayton j grant on mon 5 feb 01
when i put my long neck bottles directly into water they explode
violently into several peices so i just try to use seaweed or leaves
soaked in water but the leaves ignite and the seaweed does not and in a
residential area its best not to make alot of smoke so i just use seaweed
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Ababi on tue 6 feb 01
----- Original Message -----
From: "dayton j grant"
To:
Sent: Monday, February 05, 2001 7:38 AM
Subject: Re: Raku question
> when i put my long neck bottles directly into water they explode
> violently into several peices
This is true , and I am sorry I have forgotten it.
Another solution is not to put them to the water, but to spray water on the
bottle and into it from a hose in the same time.
Whenever it is possible, a like bowl that has a central foot, pipe -like, I
make tiny holes, in the top of the foot, to let the air a way out, when I
put the bowl to the water, to avoid blowing the piece .
Ababi Sharon
http://www.milkywayceramics.com/cgallery/asharon.htm
http://www.israelceramics.org/index.html
* * * * * * * *
www.photoisland.com
ID: sharon@shoval.org.il
Password:clay
Linda Fletcher on sat 10 feb 01
I was under the impression that immersing the pots in water was just =
great theater,
ala Paul Soldner.=20
mudsinger
Cantello Studios on sun 11 feb 01
I have always found that putting a raku pot in water des very little to the
pot other then make the crackle smaller and stress the pot, sometimes
to the breaking point. The best crackle is formed with slow cooling, and a
tight seal, keeping most of the smoke inside the can as long as one can. It
will however help release some of the carbon from the glaze surface. This
however is of little help if the pot is cracked and unusable.
Chris from Cantello Studios Chico Ca.
WHew536674@CS.COM on sun 11 feb 01
Didn't Paul Soldner immerse bottles in water and the water and steam would
spray out of the top like a geyser? Hee Haw. Me, I'll stick with the hose
and freeze the copper reds that way, safer.
Joyce A.
Marcia Selsor on thu 30 aug 01
Just refire them without any additional glaze. You can refire them many
times. Enjoy yourself. I just fired 30 pieces today in my large raku
kiln. 9:30-3:30 about 10 or more loads. Great day!
Have fun with it. If you don't like it, refire it. Sometimes you need to
put more glaze on and sometimes you don't.
Marcia Selsor in hot Montana
Liz Gardo wrote:
>
> I am new at firing raku. A group of us built a raku kiln recently.....learned
> alot the hard way. When we did the first firing, we had set the propane
> burner too far into the kiln. Needless to say, all of the glazes on the
> pieces either looked burnt or matte. We have since adjusted the burner and
> the kiln is turning out some really good pieces.
> Here's my question:
> Can any of the "burnt looking pieces" be reglazed and fired?
>
> I would certainly appreciate any advise.
>
> Thanks!
>
> ______________________________________________________________________________
> 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.
--
Marcia Selsor
selsor@imt.net
http://www.imt.net/~mjbmls
http://www.imt.net/~mjbmls/May2001.html
http://www.imt.net/~mjbmls/Tuscany2001.html
http://www.imt.net/~mjbmls/Gallery.html
Gary Ferguson on thu 30 aug 01
Liz:
Yes, you can reglaze (if needed) and refire your "burnt" Raku pieces. Every
firing increase the chance of breaks though, but if the piece is crap now,
what have you got to lose?
Gary Ferguson
pottery@garyrferguson.com
http://www.garyrferguson.com
----- Original Message -----
From: "Liz Gardo"
To:
Sent: Thursday, August 30, 2001 3:55 PM
Subject: Raku Question
> I am new at firing raku. A group of us built a raku kiln
recently.....learned
> alot the hard way. When we did the first firing, we had set the propane
> burner too far into the kiln. Needless to say, all of the glazes on the
> pieces either looked burnt or matte. We have since adjusted the burner
and
> the kiln is turning out some really good pieces.
> Here's my question:
> Can any of the "burnt looking pieces" be reglazed and fired?
>
> I would certainly appreciate any advise.
>
> Thanks!
>
>
____________________________________________________________________________
__
> 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.
Liz Gardo on thu 30 aug 01
I am new at firing raku. A group of us built a raku kiln recently.....learned
alot the hard way. When we did the first firing, we had set the propane
burner too far into the kiln. Needless to say, all of the glazes on the
pieces either looked burnt or matte. We have since adjusted the burner and
the kiln is turning out some really good pieces.
Here's my question:
Can any of the "burnt looking pieces" be reglazed and fired?
I would certainly appreciate any advise.
Thanks!
clay.music on fri 15 mar 02
I used to make large tiles and mirrors in my raku kiln. I found that if =
I heated the pieces thoroughly on top before placing on the hot shelf I =
didn't have a problem with cracking. I always made sure the glazes were =
completely dry. My removal tool of choice (which made many local potters =
laugh) was the shallow bottom of the broiler pan that came with my oven =
(come on, whose going to cook after rakuing anyway?? ) I would just rake =
with a long tong onto the broiler pan bottom and race to the reduction =
chamber. I generally heated the broiler pan up a little bit so the shock =
regular air temperature would be minimized. This "system" worked great.=20
Sara O'Neill
Geometrix Clay Designs=20
Durham, NC 27703
clay.music@verizon.net
Elizabeth Herod on sat 7 dec 02
Someone told me that the amount of white crackle depended upon what kind of
material you have in the trashcan, sawdust or newspaper. I had always been
told that it was the cooling, waving it around before putting it in the can=
,
or spritzing it with water.
I can see that the combustible creates the carbon that goes into the cracks=
,
but I didn=B9t think that it actually governed the amount of crackle.
Someone please explain this to me.
Thanks
Beth
Marcia Selsor on sat 7 dec 02
I think it is a combination of both. The crackles need a shock to
crackle,i.e. spritz, wave in the air, then they need good smoking for
the carbon to penetrate the cracks.
Marcia Selsor
Elizabeth Herod wrote:
> Someone told me that the amount of white crackle depended upon what kind of
> material you have in the trashcan, sawdust or newspaper. I had always been
> told that it was the cooling, waving it around before putting it in the can,
> or spritzing it with water.
>
> I can see that the combustible creates the carbon that goes into the cracks,
> but I didnšt think that it actually governed the amount of crackle.
>
> Someone please explain this to me.
>
> Thanks
> Beth
>
> ______________________________________________________________________________
> 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.
>
--
Tuscany in 2003
http://home.attbi.com/~m.selsor/Tuscany2003.html
"rakufool on sat 7 dec 02
Hi Beth. I think that you are partly right. But bear in mind that
how cold the ambient outside temp is probably influences how bold the
crackle will be. As does how smooth the surface of the pot is. I
think. And probably how thick the glaze is applied too. Good luck
and have fun.
best regards
Leland Hall
Before The Wheel Enterprises
La Pine OR, USA
PS. to Mel: If this post has the headers and crap, sorry. I'm
posting it through what I call the "back door". (Yahoo Groups) I'm
not sure how to use it properly and get rid of those pesky headers.
The setup is all different and I'm not used to it.
--- In clayart@yahoogroups.com, Elizabeth Herod wrote:
> Someone told me that the amount of white crackle depended upon what
kind of
> material you have in the trashcan, sawdust or newspaper. I had
always been
> told that it was the cooling, waving it around before putting it in
the can,
> or spritzing it with water.
>
> I can see that the combustible creates the carbon that goes into
the cracks,
> but I didn=B9t think that it actually governed the amount of crackle.
>
> Someone please explain this to me.
>
> Thanks
> Beth
>
>
______________________________________________________________________
________
> Send postings to clayart@l...
>
> 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@p...
Gary Ferguson on sat 7 dec 02
There are many factors that affect the crackle of a Raku glaze.
The crackle pattern is first created by the glaze shrinking faster or
slightly more than the clay. This creates the crazing (or crackle pattern).
When smoke invades this crack is appears dark and creates the line pattern.
The amount and size of the crackle pattern can be affected by the thickness
of your clay walls, texture of the clay, and the type of clay used, type of
glaze, etc.
What I generally do is:
Create a smooth surface on the pot
Glaze fairly thickly
Fire to temperature
Pull from the kiln
Hold in the air for about a minute (you should start hearing the "tinking"
sound as the crazing is created)
Put it in a reduction chamber with a combustible (like newspaper)
Cover the reduction chamber so lots of smoke is produced
Wait about 3-5 minutes
Burp the can (open it up for a few seconds so the fire starts again)
Cover it again
Burp again
Let it cool in the covered contain for around 30 minutes
Remove and dunk in water to finish cooling.
One note - I attended a Piepenburg workshop last month and he stated if you
wanted your clear crackle to stay white, do not fire in reduction or it will
turn out gray.
Hope this helps.
Gary Ferguson
Clay Artist
Nampa, ID 83687
Sign up for my Just Raku Newsletter at http://www.garyrferguson.com
----- Original Message -----
From: "Elizabeth Herod"
To:
Sent: Saturday, December 07, 2002 10:46 AM
Subject: Raku question
Someone told me that the amount of white crackle depended upon what kind of
material you have in the trashcan, sawdust or newspaper. I had always been
told that it was the cooling, waving it around before putting it in the can,
or spritzing it with water.
I can see that the combustible creates the carbon that goes into the cracks,
but I didnšt think that it actually governed the amount of crackle.
Someone please explain this to me.
Thanks
Beth
____________________________________________________________________________
__
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.
william schran on sun 8 dec 02
Beth - You asked about the amount of crackle in Raku white crackle
glaze. The crackle you achieve will be dependent on several factors,
glaze ingredients, glaze application thickness, firing temperature,
cooling time prior to post firing reduction and combustible materials
used. The area which seems to have the greatest impact is cooling
from kiln to reduction chamber. Waving around (with a tight grip on
the work), blowing air on the piece (we've used a leaf blower, again
hang on to the work) or spraying with some water (cheap plastic
bottle sprayer) have all worked for my students.
Bill - recently relocated from Manassas, Va to Fredericksburg, Va
where I can now see the stars at night.
Craig Clark on sun 8 dec 02
Beth, whoever told you that was only giving you part of the story and
I'm not all that sure that they really understand what is occurring in the
process if that is all the info that they gave.
The "crackly pattern" is the result of carbon deposition in the cracks
in the glaze. The cracks in the glaze are the result of quick cooling of the
pot after it is removed from the kiln and the resultant shrinking of the
glaze more quickly than the clay body of the pot. Just listen for a
"tinkling" type of sound as you wave the pot around in the air. You may also
increase and/or localize the crazing through the use of a sray bottle that
you use to "spritz" water onto certain areas of the pot. This will promote
secondary and tertiary crazing.
A clear or white raku glaze is designed to shrink quickly. If you want
to further this action try adding a little bit more flint to the mix.
Additionally, as has been suggested, you might try "burping" the can to
produce a second flame action after a minute or so to promote more crazing
and carbon deposition. The only problem is that the more "burn" that you get
the mudier the appearance of the finished glaze. Sometimes you will end up
with a dull grey rather than a nice bright white. You will need to play
around with the process a bit to determine what is acceptable for your
purposes. A generaly rule of thumb that works for me is to keep the burn to
a minimum if you are after a nice bright white. This is also affected by the
color of the clay body that you are using. If your clay body bisques to a
buff or darker color it is difficult to get a nice bright white. You'll
probably need to opacify your glaze considerably to get decent results. With
a body that biques to a white all you need is a clear crackle base.
Concerning the question about the type of material in the reduction can:
this is a secondary type of concern. You just want to use something that
will give you a nice rigourous flame. I use newspaper, though others have
used sawdust, rice hulls, straw, leaves, pine needles, etc. Just keep in
mind that the denser the combustion material the more apt it is to leave a
pattern of itself in the glaze surface (the reason the I use newspaper. I'm
not after a pattern.)
Hope this helps
Craig Dunn Clark
619 East 11 1/2 st
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
----- Original Message -----
From: Elizabeth Herod
To:
Sent: Saturday, December 07, 2002 9:46 AM
Subject: Raku question
Someone told me that the amount of white crackle depended upon what kind of
material you have in the trashcan, sawdust or newspaper. I had always been
told that it was the cooling, waving it around before putting it in the can,
or spritzing it with water.
I can see that the combustible creates the carbon that goes into the cracks,
but I didnšt think that it actually governed the amount of crackle.
Someone please explain this to me.
Thanks
Beth
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Janet Kaiser on sun 8 dec 02
The Rakuists will tell me if I am wrong, but surely the crackle is produced
by ANY post-firing thermal shock, no matter how it is "applied"?
And "good" crackle (not to be confused with crazing) is a glaze
specifically developed not to craze too finely. So the crackle becomes a
random and open pattern, quite unlike crazing. This has always been my idea
of a good crackle, but is it universal?
Sincerely
Janet Kaiser
******************* FROM ********************
The Chapel of Art / Capel Celfyddyd
8 Marine Crescent, Criccieth LL52 0EA, Wales, UK
Tel: ++44 (01766) 523570 URL: http://www.the-coa.org.uk
Celia Littlecreek on sun 8 dec 02
----- Original Message -----
From: "Elizabeth Herod"
Subject: Raku question
Someone told me white crackle depended .....
Here are my not so secret secrets. I like white crackle, not clear.
Then, if you don't use a white clay body, you will still have a bright,
clean , white crackle. I use a recipe from Robert Piepenburg 80% Gerstly
Borate (substitute if needed) and 20% Cornwall Stone, by volume. (By volume
means 4 cups G.B. and 1 cup C.S. or 4 yellow bowls of G.B. and 1 yellow
bowl of C.S. Kinda the way grandma used to make bread. Same measure for
everything, just more measures for one than the others:)
I brush it on thickly for large cracks, thinly for small cracks. Smooth
the surface with your fingers to get rid of bumps. I fire until the glaze
looks wet in the kiln. Take it out and put it on the ground. When it
sounds like pop corn popping, I put it in a can about the same size as the
piece, FULL of newspaper, with the lid not on tightly.
Hope this helps.
Culling on mon 9 dec 02
been watching this for a bit and have seen no mention of oil.
Our technology teacher told us of a Japanese potter who was an expert on
crackle - high fired I'm sure BUT - he used coloured oils to dunk his pots
in when they were cool enough, apparently different types of oils caused
different sized and patterned crazing and could be used consecutively with
different stains in ' em. Also no carbon to affect the colour of the glaze
thru reduction. Anyone interested in trying it - he used everything from
crank oil to different vege oils. I guess old chip fat would be free for a
trial. Only possible downside I could see for this would be the porosity of
the body and the smell of the oil being retained which would be less of a
problem with a vitrious body!!
Steph
40 degrees and horridly humid -endevouring not to drip sweat on my pots!
----- Original Message -----
From: Janet Kaiser
To:
Sent: Monday, December 09, 2002 6:01 AM
Subject: Re: Raku question
> The Rakuists will tell me if I am wrong, but surely the crackle is
produced
> by ANY post-firing thermal shock, no matter how it is "applied"?
>
> And "good" crackle (not to be confused with crazing) is a glaze
> specifically developed not to craze too finely. So the crackle becomes a
> random and open pattern, quite unlike crazing. This has always been my
idea
> of a good crackle, but is it universal?
>
> Sincerely
>
> Janet Kaiser
>
> ******************* FROM ********************
> The Chapel of Art / Capel Celfyddyd
> 8 Marine Crescent, Criccieth LL52 0EA, Wales, UK
> Tel: ++44 (01766) 523570 URL: http://www.the-coa.org.uk
>
>
____________________________________________________________________________
__
> 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.
>
MudPuppy on sun 25 sep 05
I made a sort of "cage" out of hardware cloth (which is actually a wire =
mesh).
Its shaped in a triangle and one side sets on the kiln shelf. I place =
all my small pieces inside and then when they are ready to go into the =
reduction barrel, I just lift the whole "cage" out and set it in the =
barrel.
// / --------
I can send you a photo if that helps...
Cathi Newlin, Mercer, Mo
MudPuppy@box49.com
http://www.SquarePegArts.com
----- Original Message -----=20
From: Ann Testa=20
To: CLAYART@LSV.CERAMICS.ORG=20
Sent: Sunday, September 25, 2005 8:50 PM
Subject: Raku Question
This is the time of year that I begin to realize that
it is time to start rakuing some C'mas ornaments.
I usually fire them on a bisqued plate & then transfer
them to the reduction tub by dumping them off the
plate. Occasionally, the plate breaks creating havoc
in the kiln, or cracks in the dumping process which
slows everything down.
Does anyone have an idea how to perform this task
more gracefully? The ornaments are both flat &
round with glaze on all sides.
Any ideas will be appreciated.
Ann Testa
_AnnTesta@aol.com_ (mailto:AnnTesta@aol.com)
Just attended an extruding workshop this weekend
with David Henley which was great!
=
_________________________________________________________________________=
_____
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.
Ann Testa on sun 25 sep 05
This is the time of year that I begin to realize that
it is time to start rakuing some C'mas ornaments.
I usually fire them on a bisqued plate & then transfer
them to the reduction tub by dumping them off the
plate. Occasionally, the plate breaks creating havoc
in the kiln, or cracks in the dumping process which
slows everything down.
Does anyone have an idea how to perform this task
more gracefully? The ornaments are both flat &
round with glaze on all sides.
Any ideas will be appreciated.
Ann Testa
_AnnTesta@aol.com_ (mailto:AnnTesta@aol.com)
Just attended an extruding workshop this weekend
with David Henley which was great!
Lori Leary on mon 26 sep 05
Ann,
Recently, I have been raku firing hundreds of small terra sigged forms
in the raku kiln, mainly to blacken them in post-firing reduction.
(some have a low fire glaze.) My way to speed this up was to use 4
salvaged (I knew I could use them one day!) gas stove grates with thick
steel wire to make "baskets". For each basket, I used 2 pieces of thick
steel wire folded in half, with hooks formed at the ends (I bent them in
a vise). These 2 wires criss-crossed over the grate to make handles. I
made sort of a jump ring out of a small piece of wire to hold the
handles together at the top. Just use your tongs to take the baskets
out of the kiln and dump them from the basket into the post firing
reduction chamber. I lined the baskets with small pieces of ceramic
fiber. (Use a mask when handling these) Depending on the size of your
pieces, you might not need the fiber. When firing, the wire can get
really soft, but the jump ring helps to hold it all together. The
grates have lasted through at least 50 firings, but I have had to
replace the wires once. I think now that forging some steel rod for
handles would have worked best (Another cool thing I have learned to do
in grad school), but since not everyone has a forge handy, the regular
steel wire works fine.
It's late, and I hope I have explained this clearly and it is helpful.
If you want some drawings or digital images, let me know.
Best,
Lori L.
Ann Testa wrote:
>This is the time of year that I begin to realize that
>it is time to start rakuing some C'mas ornaments.
>I usually fire them on a bisqued plate & then transfer
>them to the reduction tub by dumping them off the
>plate. Occasionally, the plate breaks creating havoc
>in the kiln, or cracks in the dumping process which
>slows everything down.
>
>Does anyone have an idea how to perform this task
>more gracefully? The ornaments are both flat &
>round with glaze on all sides.
>
>Any ideas will be appreciated.
>
>
>
>
Deborah Thuman on wed 31 jan 07
While I was in Hawaii, I bought two plants that need to be planted. I
could go to Wal-Mart and buy pots, but what fun would that be?
I was thinking of throwing a couple flower pots. I know that raku is
not food safe because it's so porous. However, is it suitable for a
flower pot? I was thinking of glazing only the outside.
Thanks.
Deb
http://debthumansblog.blogspot.com/
Sue Roessel Dura on thu 1 feb 07
On Wed, 31 Jan 2007 20:59:32 -0700, you wrote:
>I was thinking of throwing a couple flower pots. I know that raku is
>not food safe because it's so porous. However, is it suitable for a
>flower pot? I was thinking of glazing only the outside.
I've made raku flower pots and they've been fine for several years. They=
don't
hold water, which is fine for the flowers. Actually, I think the plants =
do
better in the pots I make than in commercial ones ;-) Best, Sue
Craig Clark on thu 1 feb 07
Deb, raku fired pots are indeed suitable for flower pots. Since you do
not have a vitrified clay body they act much like the typical
earthenware pots that many people use. They let the soil breath. The
thing to be concerned about is the type of raku glaze that you use. Keep
in mind that the glazes are not durable to begin with. Some are far less
durable than others. I would not, for example, use a copper matte type
of glaze on a planter. It is highly reactive and when subjected to the
oxidizing effects of watering will fade quickly. A nice white crackle is
the work horse of the bunch. It will give you service for many years
without any appreciable change. As long as you are making the pots, and
enjoying the glazing, make them whatever is most pleasing to you. Just
keep in mind that they will change.
Hope this helps
Craig Dunn Clark
619 East 11 1/2 St
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
,Deborah Thuman wrote:
> While I was in Hawaii, I bought two plants that need to be planted. I
> could go to Wal-Mart and buy pots, but what fun would that be?
>
> I was thinking of throwing a couple flower pots. I know that raku is
> not food safe because it's so porous. However, is it suitable for a
> flower pot? I was thinking of glazing only the outside.
>
> Thanks.
>
> Deb
> http://debthumansblog.blogspot.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.
>
Darnie Sizemore on thu 1 feb 07
Deborah,
I have had some negative experience with Raku
planters. The plants that have been in them have died.
My assumption is that the heavy metals leech into the
soil and kill the plant.
Good luck,
Darnie
--- Deborah Thuman wrote:
> While I was in Hawaii, I bought two plants that need
> to be planted. I
> could go to Wal-Mart and buy pots, but what fun
> would that be?
>
> I was thinking of throwing a couple flower pots. I
> know that raku is
> not food safe because it's so porous. However, is it
> suitable for a
> flower pot? I was thinking of glazing only the
> outside.
>
> Thanks.
>
> Deb
> http://debthumansblog.blogspot.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.
>
____________________________________________________________________________________
8:00? 8:25? 8:40? Find a flick in no time
with the Yahoo! Search movie showtime shortcut.
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Dannon Rhudy on thu 1 feb 07
Raku pots do not generally hold up well with plants,
though they may last a couple of years. The clay
is not a strong clay, and the inclusion of the carbon
seems to break it down fairly quickly. At least, that
is my observation.
regards
Dannon Rhudy
Lee Love on fri 2 feb 07
There are 2 things to keep in mind when trying to make raku more durable:
Most of the damage is done when you put a hot pot in water. Skip this.
Use a glaze that will seal the surface, not matt glazes.
--
Lee in Mashiko, Japan
Minneapolis, Minnesota USA
http://potters.blogspot.com/
"Let the beauty we love be what we do." - Rumi
"When we all do better. We ALL do better." -Paul Wellstone
Lee Love on sat 3 feb 07
On 2/3/07, Ivor and Olive Lewis wrote:
> If Copper salts, eg Copper sulphate, have been adsorbed into the clay during the glazing
>process then this may be leached back into the potting soil.
If you put the oxides on top of a good glaze, they are less likely
to leach into the pot.
--
Lee in Mashiko, Japan
Minneapolis, Minnesota USA
http://potters.blogspot.com/
"Let the beauty we love be what we do." - Rumi
"When we all do better. We ALL do better." -Paul Wellstone
Irene F.Gulla on sat 3 feb 07
If you put a plastic liner in your pot, the plants should do okay. I have
many pots that are raku and the plants are doing fine. Some of them have liners
and some don't and not one of them have died.
Ivor and Olive Lewis on sat 3 feb 07
If Copper salts, eg Copper sulphate, have been adsorbed into the clay =
during the glazing process then this may be leached back into the =
potting soil. Copper is recognised as a fungicide and a potent =
destroyer of other soil microorganisms that seem to be essential for the =
health of some plants.
Perhaps this should be considered.
Best regards,
Deborah Thuman on sun 19 oct 08
I'm going to be doing a raku firing the second Saturday in November
and I want to run this firing my way. The last two firings, I felt the
pieces were left in the can too long (more than a half hour for one,
and a couple days for the other). Here are my thoughts on how I want
to do this.
Pull pieces from the kiln and put in cans. Leave the tops off the cans
for 2-3 minutes for an oxidation firing. Put lids on cans and wait 15
minutes before pulling pieces from cans. Then hose off the pieces.
Anyone see any major problems with what I propose? I'm using raku clay
(commercial clay designed for raku so it's supposed to be able to
handle thermal shock) so I don't expect to have exploding pots.
Many thanks for the advice.
Deb Thuman
http://debthumansblog.blogspot.com/
http://www.etsy.com/shop.php?user_id=5888059
James F on sun 19 oct 08
Deb...
I don't know if the open burning will do anything=2C but I don't see any wa=
y it can possibly hurt=2C so I say go for it and see what happens! The bes=
t advice I ever received in ceramics was from the tech at the University of=
Michigan=2C a really gifted ceramic sculptor and great teacher named John =
Leyland. I was in the glaze room at the local college where he used to tea=
ch=2C and asked him what would happen if I did something or other that I ca=
n no longer recall. His reply was 'Try it and find out. Nothing in here c=
an blow up=2C and you'd have to really go out of your way for any of it to =
kill you.' This was absolutely the most liberating thing I had ever heard.=
It was this statement that made me realize that clay and glaze formulatio=
ns=2C kiln firing techniques and schedules=2C and most everything else in c=
eramics were not Holy Writ from on high that one needed to learn and memori=
ze. From that point on=2C whenever I heard "you can't so that"=2C I knew I=
might be on to something! Freedom to explore=2C freedom from pedantry=2C =
and especially freedom to fail are in my opinion the greatest gifts a teach=
er can bestow on the student. "Try it and find out". Words of wisdom.
The half dozen times I did raku=2C we left the pots in the cans until just =
before we needed the cans for the next batch. Since it was about 20-25 min=
utes between batches=2C your 15 minutes sounds about right.
As to quenching=2C I always plunged the pots quickly into a bucket of water=
so that I wouldn't be stressing one part of the pot more than another. I =
was absolutely amazed the first time that the piece didn't blow up. Hosing=
might be iffy=2C but if you really want to do it=2C there is only one way =
to find out (but try it on your worst piece first)! When I was assisting a=
youth ceramics class with raku=2C one little girl didn't understand the co=
ncept of "plunge". She slowly dipped her hot pot into the bucket of water =
to everyone's horror=2C but her pot (ordinary stoneware clay) survived just=
fine. Maybe rules are only for adults.
Be well.
...James
> Date: Sun=2C 19 Oct 2008 10:18:56 -0600
> From: debthuman@ZIANET.COM
> Subject: Raku question
> To: CLAYART@LSV.CERAMICS.ORG
>=20
> I'm going to be doing a raku firing the second Saturday in November
> and I want to run this firing my way. The last two firings=2C I felt the
> pieces were left in the can too long (more than a half hour for one=2C
> and a couple days for the other). Here are my thoughts on how I want
> to do this.
> Pull pieces from the kiln and put in cans. Leave the tops off the cans
> for 2-3 minutes for an oxidation firing. Put lids on cans and wait 15
> minutes before pulling pieces from cans. Then hose off the pieces.
>=20
> Anyone see any major problems with what I propose? I'm using raku clay
> (commercial clay designed for raku so it's supposed to be able to
> handle thermal shock) so I don't expect to have exploding pots.
>=20
> Many thanks for the advice.
>=20
> Deb Thuman
> http://debthumansblog.blogspot.com/
> http://www.etsy.com/shop.php?user_id=3D5888059
_________________________________________________________________
When your life is on the go=97take your life with you.
http://clk.atdmt.com/MRT/go/115298558/direct/01/=
Sherron & Jim Bowen on sun 19 oct 08
what are you burning for the oxidation? If its one of the usual combustibles
then after your oxidation period you may have to add more before you close
up the cans, especially if they aren't very well sealed, to be sure of
adequate reduction. If they are real tight then that may not be a
consideration. Have you tried alcohol for the oxidation part? If you wait
that long they may not be still changing color when you pull them. If you do
that sooner you can control the colors with a water spray.
JB
----- Original Message -----
From: "Deborah Thuman"
To:
Sent: Sunday, October 19, 2008 10:18 AM
Subject: Raku question
> Pull pieces from the kiln and put in cans. Leave the tops off the cans
> for 2-3 minutes for an oxidation firing. Put lids on cans and wait 15
> minutes before pulling pieces from cans. Then hose off the pieces.
Allyson May on mon 20 oct 08
Hey Deb,
I have been firing Raku quite a while (15yrs or so) and have tried many =
reduction techniques. I really believe that firing and reduction in =
raku are as much personal preference as anything else but I can share =
what gets results for me. If you keep firing you will find the right =
technique for your particular way of working. Here is what I do: BTW I =
fire all matte glazes.
1. Pull pieces from kiln.
2. Place in reduction bin: thin layer of sawdust on bottom with a nest =
of shredded paper on top, crumpled=20
paper around the sides.
3. Allow flames to develop; 1-2 minutes. Place crumpled paper and a =
piece of cardboard over the piece.=20
Cardboard helps blacks to develop (just my opinion).=20
4. Cover cans for about 2 minutes then remove lids and allow flames to =
develop once more. Add a little more
paper, if needed, and cover again.
5. Leave in cans for 15 min (small pieces 10-15 min and larger work =
15-20 min).
6. Remove from cans and plunge into water to cover completely. I have =
found that the water plunge cools
pieces evenly and quickly. Many of my works are slab built, tiles =
or large plates. I had a lot of breakage with=20
air cooling and spraying. Once I "took the plunge" breakage and =
cracking rarely occur. I use a wheel barrow
filled with water for cooling.
Again, its not an exact science. Keep firing and see what works best =
for you. =20
Peace,
Allyson May
Stoney Creek Pottery
Bloomington, IN
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