Gary Beckwith on wed 27 may 09
I just fired my first raku piece with my home built kiln:
http://4.bp.blogspot.com/_SRweFnA_pN8/Shr6R9i8TtI/AAAAAAAAAFQ/Ob0eZnquWPI/s=
1600-h/Newpics+018.jpg
I was told that Raku can re-oxidize over time, and that the colors can
change. Is there any way to prevent that, perhaps some kind of protective
coating that can be applied? I understand that keeping it out of direct
sunlight can help.
Thanks,
Gary Beckwith
Auburn, CA
Lee Love on thu 28 may 09
On Wed, May 27, 2009 at 8:13 PM, Gary Beckwith wro=
te:
> I just fired my first raku piece with my home built kiln:
> http://4.bp.blogspot.com/_SRweFnA_pN8/Shr6R9i8TtI/AAAAAAAAAFQ/Ob0eZnquWPI=
/s1600-h/Newpics+018.jpg
Gary, I think the main problem is with matte finishes. Yours is
glossy and should be okay.
--
Lee Love, Minneapolis
"The tea ceremony bowl is the ceramic equivalent of a sonnet: a
small-scale, seemingly constricted form that challenges the artist to
go beyond mere technical virtuosity and find an approach that both
satisfies and transcends the conventions." -- Rob Sliberman
full essay: http://togeika.multiply.com/journal/item/273/
Craig on thu 28 may 09
Gary, the most definitive explanation that I have seen on the phenomonon
is an article written by Tom Buck back in 1996.....he completely changed
the way that I looked at Raku Glazes. I have been quietly spreading the
word ever since.
I will not attempt to repeat what he has to say. Just follow the link at
the end of this paragraph and read.
http://digitalfire.com/4sight/education/first_you_see_it_then_you_dont_raku=
_glaze_stability_113.html
or here
http://ceramic-materials.com/cermat/education/113.html
If someone tries to tell you that fading does not occur, as I have been
told by folks with MFA's, and other professional potters, who ought to
know better, don't argue. They simply do not know what they are talking
about. It is not worth wasting your breath. It is kinda like trying to
argue with someone who thinks it is OK to use lead......don't argue. If
that is there choice, so be it....as long as they are not exposing others.
I tell my customers all the time that Raku glazes do not have an
archival nature. They multicolored ones will indeed fade over time,
despite some of our best efforts.
The glazes are both photoreactive and will continue to oxidize, read
rust, over time. One can use a number of techniques to seal the glaze
that will greatly extend the life of the brighter colors. One that has
worked for me is a good grout sealer. Additionally, keeping the pieces
out of direct sunlight and in a dry environment is helpful as well. If
the pot is living in a dry, rather than wet climate, the fading will not
be anywhere near as pronounced.
The problem has not happened with either the yellow or white crackle
galzes that I use. It is far more prounouced in glazes that use more
Copper Carb.....and the so called Copper Matts are the worst by far.
Hope this helps
Craig Dunn Clark
619 East 11 1/2 St
Houston, Texas 77008
(713)861-2083
(713)261-0281
http://www.flickr.com/photos/57427104@N00/
Gary Beckwith wrote:
> I just fired my first raku piece with my home built kiln:
> http://4.bp.blogspot.com/_SRweFnA_pN8/Shr6R9i8TtI/AAAAAAAAAFQ/Ob0eZnquWPI=
/s1600-h/Newpics+018.jpg
>
>
> I was told that Raku can re-oxidize over time, and that the colors can
> change. Is there any way to prevent that, perhaps some kind of
> protective
> coating that can be applied? I understand that keeping it out of direct
> sunlight can help.
>
> Thanks,
>
> Gary Beckwith
> Auburn, CA
>
William & Susan Schran User on thu 28 may 09
On 5/27/09 9:13 PM, "Gary Beckwith" wrote:
> I was told that Raku can re-oxidize over time, and that the colors can
> change. Is there any way to prevent that, perhaps some kind of protectiv=
e
> coating that can be applied? I understand that keeping it out of direct
> sunlight can help.
Copper in raku glazes that have insufficient silica can re-oxidize over
time. This is the case for many copper mats. I have an example of a pot
covered in a mottled brown glaze - used to be a lovely copper
red/blue/purple mat - that I show to my students.
Randy Broadnax said he coats his copper mats with a grout sealer that helps
to prevent re-oxidation of his copper mats.
Here's a good article by Tom Buck entitled: "First You See It Then You
Don't: Raku Glaze Stability"
Bill
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
Vince Pitelka on thu 28 may 09
Lee Love wrote:
"Gary, I think the main problem is with matte finishes. Yours is
glossy and should be okay."
Lee and Gary -
The gloss copper penny finishes are just as vulnerable. Within five or six
years they will be green. The reduction process, both in-kiln and
post-firing, causes the metal oxides on the surface to convert to a pure
metallic copper coating - it is right there on the surface and not within
the glassy glaze. As you no doubt know, the subsequent reaction is exactly
the same as what happens to a shiny piece of copper sculpture when left out
in the garden for a few years - it oxidizes to green.
I think this is one of the main reasons so many people have grown tired of
and turned away from American raku. From my own perspective, I cannot
imagine making and firing a fine piece of handmade ceramic work and then
having to put a coat of plastic sealer on it to keep it from changing
colors. To me that pretty much defeats the whole purpose of doing somethin=
g
that has to survive the firing process.
I can understand the enthusiasm of anyone who discovers raku for the first
time, but it is very important to realize that the most popular raku effect=
s
(copper matt, copper flash, copper penny, alkaline blue-green, white
crackle) have been done to death over the past 40 years. I apologize for
being the curmudgeon here. My intent is not to discourage anyone from
getting into raku, but instead to challenge them to come up with new ideas
and new effects. The raku process itself is so immediate and exciting, and
I'd like to see the American raku aesthetic revived with some new
information and techniques.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
steve graber on thu 28 may 09
the wh=3D
for me, using copper glazes, keep out of direct sunlight.=3DA0=3DA0=3D0A=3D=
0Athe wh=3D
ite's seem very stable.=3DA0 =3D0A=3DA0Steve Graber, Graber's Pottery, Inc=
=3D0AClar=3D
emont, California USA=3D0AThe Steve Tool - for awesum texture on pots! =3D0=
Awww=3D
.graberspottery.com steve@graberspottery.com =3D0A=3D0A=3D0A=3D0A=3D0A_____=
__________=3D
_________________=3D0AFrom: Gary Beckwith =3D0ATo: =
Clay=3D
art@LSV.CERAMICS.ORG=3D0ASent: Wednesday, May 27, 2009 6:13:13 PM=3D0ASubje=
ct: =3D
Raku - Re-Oxidize?=3D0A=3D0AI just fired my first raku piece with my home b=
uilt=3D
kiln:=3D0Ahttp://4.bp.blogspot.com/_SRweFnA_pN8/Shr6R9i8TtI/AAAAAAAAAFQ/Ob=
0e=3D
ZnquWPI/s1600-h/Newpics+018.jpg=3D0A=3D0AI was told that Raku can re-oxidiz=
e ov=3D
er time, and that the colors can=3D0Achange.=3DA0 Is there any way to preve=
nt t=3D
hat, perhaps some kind of protective=3D0Acoating that can be applied?=3DA0 =
I un=3D
derstand that keeping it out of direct=3D0Asunlight can help.=3D0A=3D0AThan=
ks,=3D0A=3D
=3D0AGary Beckwith=3D0AAuburn, CA=3D0A=3D0A=3D0A=3D0A
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