Tony Ferguson on wed 30 oct 02
Bob,
I have been somewhat successful with developing a glaze that seems to only
craze on its outer skin. I have tested my teabowls and they do not leak or
pass water to the underside. What I need to test for is how the outer skin,
having aborbed the smoke in the slight reduction, may affect the flavor of
tea.
Thank you.
Tony Ferguson
On Lake Superior, where the sky meets the Lake
Stoneware, Porcelain, Raku
www.aquariusartgallery.com
218-727-6339
315 N. Lake Ave
Apt 312
Duluth, MN 55806
----- Original Message -----
From:
To:
Sent: Wednesday, October 30, 2002 6:18 PM
Subject: Re: functional raku glazes
> Tony:
> I'm not sure how much Raku you have done, but in reduction firing the
pottery
> must be quenched with water to retain the metallic finish, but you will
get
> cracks in the glaze. Cracked glaze will not be functional. As far as I
know
> the only crack free surface would be to do an oxidation fire and allow it
to
> cool slowly to prevent cracking of the glaze.
>
> Bob Wicks, Prof. Emeritus
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
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>
Dannon Rhudy on wed 30 oct 02
Bob said:
.....>
> I'm not sure how much Raku you have done, but in reduction firing the
pottery
> must be quenched with water to retain the metallic finish, .....
I have often fired metallic raku glazes, and never ever quench
in water. Quenching is certainly a quick-cool method- but, since
it does not work well with bottle forms (they snap off at the neck,
often), I learned early that quenching is quick, but in no way
a necessity. I've done open forms both quenched and un-
quenched. No difference in the glazes, metallic or otherwise,
in my experience.
regards
Dannon Rhudy
Tony Ferguson on wed 30 oct 02
Does anyone have any functional/safe raku glazes? I am especially looking
for a black glaze and a white that will hold water over night. I use a
majolica base that works pretty well. Curious if others have anything they
like to use.
Thank you.
Tony Ferguson
On Lake Superior, where the sky meets the Lake
Stoneware, Porcelain, Raku
www.aquariusartgallery.com
218-727-6339
315 N. Lake Ave
Apt 312
Duluth, MN 55806
----- Original Message -----
From: "mel jacobson"
To:
Sent: Wednesday, October 30, 2002 8:29 AM
Subject: liners/raku
> i should have said.
> flu liners, wrapped in wire...sprayed
> with four thin coats of itc.
>
> they last a long, long, time.
> mel
>
> thanks tony.
> From:
> Minnetonka, Minnesota, U.S.A.
> web site: my.pclink.com/~melpots
> or try: http://www.pclink.com/melpots
>
>
____________________________________________________________________________
__
> 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.
>
Snail Scott on wed 30 oct 02
At 03:46 PM 10/30/02 -0800, you wrote:
>Does anyone have any functional/safe raku glazes? I am especially looking
>for a black glaze and a white that will hold water over night...
Seems to me it's not the glaze you need to worry about,
but the crazing which seems to be inevitable when a
high-fire clay is not brought to maturity (as is usual
with raku), aggravated by the absorbency of that
underfired clay. Seems to me you'd have better luck
if you focus on the clay body instead. Maybe a body
that can be bisqued to a point closer to vitrification,
with kyanite or some such thing added to help with the
thermal shock during raku?
-Snail
BobWicks@AOL.COM on wed 30 oct 02
Tony:
I'm not sure how much Raku you have done, but in reduction firing the pottery
must be quenched with water to retain the metallic finish, but you will get
cracks in the glaze. Cracked glaze will not be functional. As far as I know
the only crack free surface would be to do an oxidation fire and allow it to
cool slowly to prevent cracking of the glaze.
Bob Wicks, Prof. Emeritus
Leland G. Hall on thu 31 oct 02
On Wed, 30 Oct 2002 21:18:32 EST, BobWicks@AOL.COM wrote:
>Tony:
>I'm not sure how much Raku you have done, but in reduction firing the
pottery
>must be quenched with water to retain the metallic finish, but you will get
>cracks in the glaze. Cracked glaze will not be functional. As far as I
know
>the only crack free surface would be to do an oxidation fire and allow it
to
>cool slowly to prevent cracking of the glaze.
>
>Bob Wicks, Prof. Emeritus
>Hi. My experience indicates that it is not true that "in reduction firing
the pottery must be quenched with water to retain the metallic finish"
I often obtain metallic lusters (not that Tony said he was seeking
metallics) by slow cooling in totally oxygen free atmosphere, and often
with little or no crazing, depending on how closely the volume of the
reduction container matches the size of the vessle. Reduceing in the kiln
prior to post fireing reduction helps with metallics too.
> Leland Hall, Before The Wheel Enterprises, La Pine
Oregon______________________________________________________________________
______
>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.
Lee Burningham on thu 31 oct 02
Howdy,
How did it ever get cast in stone that you had to quench raku pots in water
for whatever purpose? I fire hundreds, or thousands of them, every year,
gave up on the water quenching 10 years ago and haven't noticed a difference
other than reducing the amount of lost pots shattered during the quenching
process.
Lee Burningham
Pottery teacher
Box Elder high school
northern utah
Bob Pulley on thu 31 oct 02
I used to make some semi-functional raku. I wasn't particularly
concerned about crackles. But when a friend told me the glaze was
wearing off the bottom of her mixing bowl I quit the practice. The
problem with most raku is that at such a low temperature the glaze is
not really bonded to the clay the way it is at a higher temperature. At
high temperatures there is a zone where the glaze causes the claybody to
flux and the two are welded together. I suspect that in raku the fit is
not as deep.
Bob
>>> fergy@CPINTERNET.COM 10/31/02 12:48AM >>>
Bob,
I have been somewhat successful with developing a glaze that seems to
only
craze on its outer skin. I have tested my teabowls and they do not
leak or
pass water to the underside. What I need to test for is how the outer
skin,
having aborbed the smoke in the slight reduction, may affect the flavor
of
tea.
Thank you.
Tony Ferguson
On Lake Superior, where the sky meets the Lake
Stoneware, Porcelain, Raku
www.aquariusartgallery.com
218-727-6339
315 N. Lake Ave
Apt 312
Duluth, MN 55806
----- Original Message -----
From:
To:
Sent: Wednesday, October 30, 2002 6:18 PM
Subject: Re: functional raku glazes
> Tony:
> I'm not sure how much Raku you have done, but in reduction firing
the
pottery
> must be quenched with water to retain the metallic finish, but you
will
get
> cracks in the glaze. Cracked glaze will not be functional. As far
as I
know
> the only crack free surface would be to do an oxidation fire and
allow it
to
> cool slowly to prevent cracking of the glaze.
>
> Bob Wicks, Prof. Emeritus
>
>
____________________________________________________________________________
__
> 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.
>
______________________________________________________________________________
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.
Alisa Liskin Clausen on thu 31 oct 02
I thought, or mean, that this is a contradiction. There are of course many
other opinions on the word "functional". Many use cracked teabowls,etc.
daily, so they function for them. I would hazard to say that John and
Ron's book would not rank raku glazes in the functional category after their
definition.
Secondly, I learned in college that I had to freeze the reduction, holding
the metallic surfaces, by throwing the pots in water. Later, I was taught
that putting in raku pots in water is only necessary if you need to crack
you pot into pieces.
My usual Raku glaze (90% any frit, 10 % Ball Clay) is never quenched and the
cracks are very visible after reduction.
regards from Alisa in Denmark
winter winter winter
william schran on fri 1 nov 02
Tony - I think "functional raku glaze" is probably an oxymoron! Given
the glaze/clay fit, the thermal shock of the firing process and
post-firing techniques, you'll more then likely always have crazing.
Bill
Michelle Lowe on mon 11 nov 02
At 03:46 PM 10/30/2002 -0800, you wrote:
>Does anyone have any functional/safe raku glazes? I am especially looking
>for a black glaze and a white that will hold water over night. I use a
>majolica base that works pretty well. Curious if others have anything they
>like to use.
>
Hi Tony,
For raku pieces that hold water, a woman who works in my studio rakus all of her work, they are slab-built "meditative pools" for tabletops. She then seals them with two-part epoxy sealer and they hold water indefinitely, without leaking or soaking through. I don't know the brand-name that she uses, but I can find out, and this would not be food-safe probably, but they do hold water. Not a glaze, but hope it helps anyway!
Mishy, fresh from the Paul Lewing workshop this weekend, inspiring, entertaining and educational!
-----------
Michelle Lowe potter in the Phoenix desert
http://www.desertdragonpottery.com
Mishy@desertdragonpottery.com
mishlowe@amug.org
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