John Goode on tue 26 jul 11
At a friends house she showed me her raku collection and the ones that were
in the sun faded over the years.
Is this true with all raku or just these at the house with extreme west
coast sun?
Thanks John
William & Susan Schran User on tue 26 jul 11
On 7/26/11 4:17 AM, "John Goode" wrote:
> At a friends house she showed me her raku collection and the ones that we=
re
> in the sun faded over the years.
> Is this true with all raku or just these at the house with extreme west
> coast sun?
Unless the glaze has been formulated properly with sufficient glass forming
materials, the copper will oxidize over time and turn to mud. In bright
sunshine the action is accelerated.
Here's a good article written by our dear departed friend Yom Buck:
u
_glaze_stability_113.html>
Bill
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
James Freeman on tue 26 jul 11
John...
A couple of my low fire sculptural glazes are rather unstable, and sometime=
s
lose their intense colors with prolonged exposure to sunlight. I have take=
n
to spraying them with Krylon Clear UV, and the problem has abated. I
originally used clear lacquer, but the Krylon Clear UV seems to work just a=
s
well, and has fewer application problems. I don't do raku too often, but
when I do, I also spray the metallic glazed pieces with lacquer or Krylon t=
o
protect them from the re-oxidation that Bill mentioned. I know it's
cheating, but they are only decorative objects anyway.
Take care.
...James
James Freeman
"...outsider artists, caught in the bog of their own consciousness, too
preciously idiosyncratic to be taken seriously."
"All I say is by way of discourse, and nothing by way of advice. I should
not speak so boldly if it were my due to be believed."
-Michel de Montaigne
http://www.jamesfreemanstudio.com
http://www.flickr.com/photos/jamesfreemanstudio/
http://www.jamesfreemanstudio.com/resources
On Tue, Jul 26, 2011 at 4:17 AM, John Goode wrote=
:
> At a friends house she showed me her raku collection and the ones that we=
re
> in the sun faded over the years.
> Is this true with all raku or just these at the house with extreme west
> coast sun?
> Thanks John
>
John Goode on tue 26 jul 11
Thank You Bill.
These are not brown but could be.I should have known digi fire would have =
a
Tom Buck story.
Curiousity piqued my interest too.I Imagine Seriuos Raku will take some tim=
e
for more clay lessons.Clayart rocks!!
John Goode
On Tue, Jul 26, 2011 at 5:52 AM, William & Susan Schran User <
wschran@cox.net> wrote:
> On 7/26/11 4:17 AM, "John Goode" wrote:
>
> > At a friends house she showed me her raku collection and the ones that
> were
> > in the sun faded over the years.
> > Is this true with all raku or just these at the house with extreme west
> > coast sun?
>
> Unless the glaze has been formulated properly with sufficient glass formi=
ng
> materials, the copper will oxidize over time and turn to mud. In bright
> sunshine the action is accelerated.
>
> Here's a good article written by our dear departed friend Yom Buck:
> <
> http://digitalfire.com/4sight/education/first_you_see_it_then_you_dont_ra=
ku
> _glaze_stability_113.html>
>
> Bill
>
> --
> William "Bill" Schran
> wschran@cox.net
> wschran@nvcc.edu
> http://www.creativecreekartisans.com
>
>
>
>
John Britt on tue 26 jul 11
I'm with Bill here, but I don't even think that if it is formulated corre=
=3D
ctly it will stop=3D20
it. I noticed this early on with raku and that is why I stopped doing it.=
=3D
Had the=3D20
greatest stuff and put it in a window in Dallas TX (intense sun!) and it =
=3D
faded in=3D20
less than 3 months.=3D20
Johnbrittpottery.com
John Goode on tue 26 jul 11
Thanks James and John.I avoided a tragic job by stopping a designer from
begging for a raku tile job sometime back.
Sometimes its not correct to be a jack of all trades.In this case a jack of
all clays.
I will advise my friend to keep her raku pieces out of a sunny room
John Goode
On Tue, Jul 26, 2011 at 6:12 AM, John Britt wro=
te:
> I'm with Bill here, but I don't even think that if it is formulated
> correctly it will stop
> it. I noticed this early on with raku and that is why I stopped doing it.
> Had the
> greatest stuff and put it in a window in Dallas TX (intense sun!) and it
> faded in
> less than 3 months.
>
> Johnbrittpottery.com
>
Lee on tue 26 jul 11
On Tue, Jul 26, 2011 at 7:52 AM, William & Susan Schran User
wrote:
> Unless the glaze has been formulated properly with sufficient
>glass forming materials,
This really has no relationship to the copper mat surfaces you find
on American raku. To add glass would eliminate the mat effect of
these "modern" treatments.
If you look at the old raku tea bowls, they have kept their
colors through the ages. I do non-leadfritted glazes in Raku and
while not colorful, do not change because of exposure to the
atmosphere (they do age with use.)
It might be possible to seal the surfaces with a "non-food"
mat material. But I am not familiar with it.
--
=3DA0Lee Love in Minneapolis
http://mingeisota.blogspot.com/
=3DA0"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D9=
7that is, =3D
"The
land of eternal youth is behind the house, a beautiful land fluent
within itself." -- John O'Donohue
William & Susan Schran User on wed 27 jul 11
On 7/26/11 2:14 PM, "Lee" wrote:
> On Tue, Jul 26, 2011 at 7:52 AM, William & Susan Schran User
> wrote:
>> Unless the glaze has been formulated properly with sufficient
>> glass forming materials,
> This really has no relationship to the copper mat surfaces you find
> on American raku. To add glass would eliminate the mat effect of
> these "modern" treatments.
The original post never specified copper mat glazes, thought the pots in
question could have that glaze on them. I have also seen copper bearing
gloss glazes that have also faded over the years. So it really doesn't
matter, if the copper raku glaze is poorly formulated, it can change color
over time due to re-oxidation.
> If you look at the old raku tea bowls, they have kept their
> colors through the ages. I do non-leadfritted glazes in Raku and
> while not colorful, do not change because of exposure to the
> atmosphere (they do age with use.)
Traditional raku was not exposed to post-firing reduction, so this has no
relationship to the original question.
> It might be possible to seal the surfaces with a "non-food"
> mat material. But I am not familiar with it.
One can use a clear spray lacquer to seal the surface. This is something Do=
n
Ellis does with his copper mats that are reduced with alcohol and they seem
to stay mat. I would imagine one would nee to make certain ALL surfaces,
including inside and bottom where sealed to prevent re-oxidation.
I have also heard grout sealer will also work. Anything that will seal the
surface form exposure to the atmosphere should retard re-oxidation. Whether
it stops it completely is probably unknown.
Bill
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
John Hesselberth on wed 27 jul 11
Hi Bill,
I would surmise that if the color is produced by post-firing reduction, =3D
it will be susceptible also to post firing oxidation over the weeks, =3D
months, or years. Post firing reduction is mostly going to change the =3D
color of those metal molecules near the surface of the glaze. And, of =3D
course, copper is a favorite ingredient for raku glazes. That copper =3D
which is near the surface will get reduced to metallic copper and will =3D
be subject to re-oxidation over time. Surface coatings or inherent glaze =
=3D
stability might change the rate a bit, but they will not stop the =3D
process. They might delay it enough for the buyer to forget who she =3D
bought it from. In any case, the post firing oxidation will take longer =3D
as the temperature will be much lower. White raku glazes, of course, =3D
would be virtually unaffected, nor would any colorant whose reduced and =3D
oxidized states are similar in color.
Regards,
John
On Jul 27, 2011, at 7:59 AM, William & Susan Schran User wrote:
> The original post never specified copper mat glazes, thought the pots =3D
in
> question could have that glaze on them. I have also seen copper =3D
bearing
> gloss glazes that have also faded over the years. So it really doesn't
> matter, if the copper raku glaze is poorly formulated, it can change =3D
color
> over time due to re-oxidation.
Lee on wed 27 jul 11
Bill,
It is the nature of the mat post-reduced American raku glazes to
fade in color, no matter how they are formulated. PERIOD. So
formulation has no relevance. If you are concerned with your work
lasting through time, traditional raku is relevant.
Like John says about post firing coatings: "They might delay
it (fading) enough for the buyer to forget who she bought it from."
If folks understand that your work is only temporary,
non-functional an throwaway, then there is no problem. But if you are
hiding its nature, then it isn't Sine Cera (without wax.)
(It is said that in ancient Rome, craftsmen would use wax to cover
imperfections in their marble sculptures, and that =3D93sine cera=3D94 was =
a
phrase commonly used by those presenting the sculptures.)
I use the same boro-litium fritted glaze as Mel. It is
functional, especially if you let it air cool after post firing
reduction.
When ever I use it or a pot with it on it, I will thank Kurt Wild.
I've renamed it in my book Kurt Wild TAK Fat White.
Tak Fat White Raku Glaze
Comments: A Kurt Wild glaze, it came from a student named Takahara.
Fat white, big crackle
Give it time to cool just a second/deep reduction
frit 3134 100
silica 6
epk 10
tin or opax 10 If you want a clear leave this out. Bentonite will
help suspend it.
Takes copper well: blue/green to red/blood .
Variations --
Takes copper well
Leave out tin for clear
--
=3DA0Lee Love in Minneapolis
http://mingeisota.blogspot.com/
=3DA0"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D9=
7that is, =3D
"The
land of eternal youth is behind the house, a beautiful land fluent
within itself." -- John O'Donohue
Gregory on thu 28 jul 11
I use Spray Thomson Water seal. I have a piece from 1994, has not faded.
Eric Hansen on thu 28 jul 11
The effect is temporary. It isn't really raku, its lustre.
- e -
On Tue, Jul 26, 2011 at 4:17 AM, John Goode wrote=
:
> At a friends house she showed me her raku collection and the ones that we=
re
> in the sun faded over the years.
> Is this true with all raku or just these at the house with extreme west
> coast sun?
> Thanks John
>
--
Eric Alan Hansen
Stonehouse Studio Pottery
Alexandria, Virginia
americanpotter.blogspot.com
thesuddenschool.blogspot.com
hansencookbook.blogspot.com
"Simplify, simplify, simplify" - Thoreau
John Britt on thu 28 jul 11
Eric,=3D20=3D20
You got it. Luster and copper matt as well as the black smoking. I have s=
=3D
een the=3D20
black fade.
Johnbrittpottery.com
John Goode on thu 28 jul 11
Thanks everybody its the gold, copper and even the black...faded.
I will take pics and send them to you if you want too see.Email me to get
them anyone.or will post to Fb page for sure
Will probably run into the artist(s) tomorrow at the Filbur fest in Comax B=
C
Canada.
Not complaining and not knocking the artist just understanding the sun and
its power on glazes.
As always amazed at the knowlege shared here :)
Nice day in clay. John Goode
,
On Thu, Jul 28, 2011 at 9:17 AM, John Britt wro=
te:
> Eric,
>
> You got it. Luster and copper matt as well as the black smoking. I have
> seen the
> black fade.
>
> Johnbrittpottery.com
>
Eric Hansen on thu 28 jul 11
Look at it like the cherry blossom or any other attribute of the
floating world - unglazed low fire surfaces for example - they really
aren't archival quality but they can be quite nice. I looked at some
really old Pre-Columbian stuff on my Mexico trip; they aged well but
still temporary surfaces. The closer you get to porcelain the closer
you get to archival quality. Unless your stoneware is VERY well fired.
- h a n s e n -
On Thu, Jul 28, 2011 at 4:20 PM, John Goode wrote=
:
> Thanks everybody its the gold, copper and even the black...faded.
> I will take pics and send them to you if you want too see.Email me to get
> them anyone.or will post to Fb page for sure
> Will probably run into the artist(s) tomorrow at the Filbur fest in Comax=
BC
> Canada.
> Not complaining and not knocking the artist just understanding the sun an=
d
> its power on glazes.
> As always amazed at the knowlege shared here :)
> Nice day in clay. John Goode
> ,
> On Thu, Jul 28, 2011 at 9:17 AM, John Britt w=
rote:
>
>> Eric,
>>
>> You got it. Luster and copper matt as well as the black smoking. I have
>> seen the
>> black fade.
>>
>> Johnbrittpottery.com
>>
>
--
Eric Alan Hansen
Stonehouse Studio Pottery
Alexandria, Virginia
americanpotter.blogspot.com
thesuddenschool.blogspot.com
hansencookbook.blogspot.com
"Simplify, simplify, simplify" - Thoreau
Eric Hansen on thu 28 jul 11
I was wondering if in high-fire iron saturate glazes which precipitate
mettallic tones - if the effect is permanent???
- h -
On Thu, Jul 28, 2011 at 5:25 PM, Eric Hansen
wrote:
> Look at it like the cherry blossom or any other attribute of the
> floating world - unglazed low fire surfaces for example - they really
> aren't archival quality but they can be quite nice. I looked at some
> really old Pre-Columbian stuff on my Mexico trip; they aged well but
> still temporary surfaces. The closer you get to porcelain the closer
> you get to archival quality. Unless your stoneware is VERY well fired.
> - h a n s e n -
>
> On Thu, Jul 28, 2011 at 4:20 PM, John Goode wro=
te:
>> Thanks everybody its the gold, copper and even the black...faded.
>> I will take pics and send them to you if you want too see.Email me to ge=
t
>> them anyone.or will post to Fb page for sure
>> Will probably run into the artist(s) tomorrow at the Filbur fest in Coma=
x BC
>> Canada.
>> Not complaining and not knocking the artist just understanding the sun a=
nd
>> its power on glazes.
>> As always amazed at the knowlege shared here :)
>> Nice day in clay. John Goode
>> ,
>> On Thu, Jul 28, 2011 at 9:17 AM, John Britt =
wrote:
>>
>>> Eric,
>>>
>>> You got it. Luster and copper matt as well as the black smoking. I have
>>> seen the
>>> black fade.
>>>
>>> Johnbrittpottery.com
>>>
>>
>
>
>
> --
> Eric Alan Hansen
> Stonehouse Studio Pottery
> Alexandria, Virginia
> americanpotter.blogspot.com
> thesuddenschool.blogspot.com
> hansencookbook.blogspot.com
> "Simplify, simplify, simplify" - Thoreau
>
--
Eric Alan Hansen
Stonehouse Studio Pottery
Alexandria, Virginia
americanpotter.blogspot.com
thesuddenschool.blogspot.com
hansencookbook.blogspot.com
"Simplify, simplify, simplify" - Thoreau
ivor and olive lewis on fri 29 jul 11
It is my understanding that low temperature reduction firings of
Copper(Oxide or Carbonate) glazes, especially if there was a high proportio=
n
of copper in the glaze, produced a surface that is prone to Atmospheric
Degradation. Under the influence of Water Vapour and Carbon Dioxide as a
components of the Air Copper metal and Red Copper oxide change to Basic
Copper Carbonate, This is familiar as the green/blue green patina on copper
clad church rooves.
Which may explain the observation that such copper glazes respond by
retaining there original colour when treated with an impervious lacquer.
Regards,
Ivor Lewis,
REDHILL,
South Australia
ivor and olive lewis on fri 29 jul 11
Dear Eric Hansen,
You ask "I was wondering if in high-fire iron saturate glazes which
precipitate metallic tones - if the effect is permanent???"'
Fired under the same conditions as the Raku and stored under the same
conditions only experimentation and exposure would show.
But fired under the same high temperature conditions as a stable glaze whic=
h
produces long lasting Copper Reds I would expect permanence from a saturate=
d
Iron Glaze.
I get a wonderful steel blue crystal from a slip that contains about 50
percent red iron oxide.
Regards,
Ivor Lewis,
REDHILL,
South Australia
James A. Monk on sat 30 jul 11
Raku, may also faded due the exposure to oxygen. One way to preserve the
patina of Raku is to spray it with matching lacquer, glossy or matt. When I
polish my brass items, I spray them with a lacquer, this will help to
maintain the polish, until the lacquer begins to yellow.
James Alton Monk
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