Steve Slatin on sat 30 jul 05
Veena --
At cone 6 and in oxidation, rutile makes nearly
everything go gold -- you just need to get the
concentration right. (I find equal weights rutile and
frit 3134 makes a great gold over a glossy finish, but
a dull note over a matte. I intend to try 35/65 for
matte glazes, and experiment from there, but haven't
gotten around to it yet.) What makes it happen is a
bit more difficult, but I'd note the following things
--
1 - rutile is largely titanium, which makes a clear
glaze go yellow, until you use too much and it then
becomes an opacifier. In fact, in concentrations that
make a thin covering go yellow in the glaze, a thick
application will sometimes go quite white. (rutile
starts out as tetragonal crystals) Some rutile
minerals are naturally yellow (sphene, for example,
can be yellow or green), so it appears to be a natural
color for Ti.
2 -- the second most prevalent element in rutile is
iron, which makes most things go brown in oxidation
below cone 10. Iron sulfide, (FeS2), interestingly,
is 'fools gold.' The iron and sulpher (which has a
native color of yellow) in this tight crystalline form
become gold in color. (the crystals are isometric
) The crystals can
be extremely regular.
3 -- If you look with a loupe or other magnifier at
the gold parts of a rutile wash on your glaze, you'll
see a magnificent series of crystals apparently
forming within the glaze. Each visible surface seems
quite square, as would be expected of an isometric
crystal.
Now, some may condemn me for trying to conduct science
in a public forum. But points 1 and 2 are well-
established, and point 3 is something you can confirm
yourself. I'm going to say, in answer to your
question "what makes it go gold" that a good
hypothesis would be that the Ti and/or Fe are forming
tiny isometric crystals within the glaze at or near
its vitrification temperature, and are suspended
inside of the cooling glaze, where their perfectly
formed, smooth, flat surfaces reflect brightly the
yellowish color we see as 'gold.'
Probably not what you were looking for, but now I have
a problem to play with as I go to sleep tonight ...
how can one test the individual crystals within a
glaze to see precisely what they're made of? Or, more
probable, how to eliminate other possible sources of
the color in a series of tests that won't require any
expensive lab equiment I don't have?
Best wishes -- Steve Slatin
--- VeenaRaghavan@CS.COM wrote:
> Hi fellow Clayarters,
>
> I am experimenting, which is one of the joys of
> being a potter. Could someone
> please tell me what it is that makes a rutile wash
> go gold on Tenmoku? I want
> to try and use the same chemical effect but without
> using the Tenmoku as a
> glaze. Hope this makes some sense!
>
> Thank you in advance for any help
>
> Veena
Steve Slatin --
Frail my heart apart and play me little Shady Grove
Ring the bells of Rhymney till they ring inside my head forever
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
VeenaRaghavan@CS.COM on sat 30 jul 05
Hi fellow Clayarters,
I am experimenting, which is one of the joys of being a potter. Could someone
please tell me what it is that makes a rutile wash go gold on Tenmoku? I want
to try and use the same chemical effect but without using the Tenmoku as a
glaze. Hope this makes some sense!
Thank you in advance for any help
Veena
VeenaRaghavan@cs.com
Steve Irvine on sat 30 jul 05
Hi Veena,
Rutile is the principal ore of titanium dioxide, and it is that material which interacts with the iron
in tenmoku to make a gold colour.
For brushwork I use a 50/50 mixture of titanium dioxide and gerstley borate to get a gold on
tenmoku, and it also has a nice opalescent effect on copper reds.
Steve
http://www.steveirvine.com
On Sat, 30 Jul 2005 10:46:54 EDT, VeenaRaghavan@CS.COM wrote:
>Hi fellow Clayarters,
>
>I am experimenting, which is one of the joys of being a potter. Could someone
>please tell me what it is that makes a rutile wash go gold on Tenmoku? I want
>to try and use the same chemical effect but without using the Tenmoku as a
>glaze. Hope this makes some sense!
>
>Thank you in advance for any help
>
>Veena
>
>VeenaRaghavan@cs.com
marianne kuiper milks on sat 30 jul 05
Hello Veena...
This answer is really useless, because I just had a
gorgeous gold(en yellow) more or less the same way.
I sprayed Tenmoku on stoneware, then yellow salt over
it, some places heavier than others. In the lighter
sprayed places I have a beautiful honey color
(although I don't like it, I do admit that it is
beautiful) and the rest a smooth light golden color
that seems alive in the sunlight.
I thought that this info may fit in somewhere. Oh..it
was fired at ^10 reduction.
Good luck, Marianne
--- VeenaRaghavan@CS.COM wrote:
> Hi fellow Clayarters,
>
> I am experimenting, which is one of the joys of
> being a potter. Could someone
> please tell me what it is that makes a rutile wash
> go gold on Tenmoku? I want
> to try and use the same chemical effect but without
> using the Tenmoku as a
> glaze. Hope this makes some sense!
>
> Thank you in advance for any help
>
> Veena
>
> VeenaRaghavan@cs.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.
>
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
Ingeborg Foco on sat 30 jul 05
Veena,
Try 50/50 rutile/ gerstley borate. It works for me firing to ^10 R. Don't
put it on too thick as it tends to bubble and isn't as attractive.
Sincerely,
Ingeborg
the Potter's Workshop & Gallery
P.O. Box 510
3058 Stringfellow Road
St. James City, Florida 33956
239-283-2775
>
> I am experimenting, which is one of the joys of being a potter. Could
someone
> please tell me what it is that makes a rutile wash go gold on Tenmoku? I
want
> to try and use the same chemical effect but without using the Tenmoku as a
> glaze. Hope this makes some sense!
>
> Thank you in advance for any help
>
>
Paul Lewing on sat 30 jul 05
Try that same oxide mixture on any dark glaze. I've used it on cobalt blue,
chrome green, copper red, even celadon.
Paul Lewing, Seattle
Jane Murray-Smith on sun 31 jul 05
So maybe you can tell me why titainium dioxide at 5% gave browny grey
mottled effects, and 2% went pale gold in this base glaze from Tony Hansens
Digital Fire site...(I was trying for little cream crystals!)..or is it just
a matter of cooling slower....
WOLLASTONITE 5.50
CUSTER SPAR 28.50
EPK 28.00
SILICA 15.00
DOLOMITE 19.00
GERSTLEY BORATE 4.00
I could send a photo...
Thanks
Jane
----- Original Message -----
From: "Steve Slatin"
To:
Sent: Saturday, July 30, 2005 11:33 PM
Subject: Re: Gold color from rutile on Tenmoku
> Veena --
>
> At cone 6 and in oxidation, rutile makes nearly
> everything go gold -- you just need to get the
> concentration right. (I find equal weights rutile and
> frit 3134 makes a great gold over a glossy finish, but
> a dull note over a matte. I intend to try 35/65 for
> matte glazes, and experiment from there, but haven't
> gotten around to it yet.) What makes it happen is a
> bit more difficult, but I'd note the following things
> --
>
> 1 - rutile is largely titanium, which makes a clear
> glaze go yellow, until you use too much and it then
> becomes an opacifier. In fact, in concentrations that
> make a thin covering go yellow in the glaze, a thick
> application will sometimes go quite white. (rutile
> starts out as tetragonal crystals) Some rutile
> minerals are naturally yellow (sphene, for example,
> can be yellow or green), so it appears to be a natural
> color for Ti.
>
> 2 -- the second most prevalent element in rutile is
> iron, which makes most things go brown in oxidation
> below cone 10. Iron sulfide, (FeS2), interestingly,
> is 'fools gold.' The iron and sulpher (which has a
> native color of yellow) in this tight crystalline form
> become gold in color. (the crystals are isometric
> ) The crystals can
> be extremely regular.
>
> 3 -- If you look with a loupe or other magnifier at
> the gold parts of a rutile wash on your glaze, you'll
> see a magnificent series of crystals apparently
> forming within the glaze. Each visible surface seems
> quite square, as would be expected of an isometric
> crystal.
>
> Now, some may condemn me for trying to conduct science
> in a public forum. But points 1 and 2 are well-
> established, and point 3 is something you can confirm
> yourself. I'm going to say, in answer to your
> question "what makes it go gold" that a good
> hypothesis would be that the Ti and/or Fe are forming
> tiny isometric crystals within the glaze at or near
> its vitrification temperature, and are suspended
> inside of the cooling glaze, where their perfectly
> formed, smooth, flat surfaces reflect brightly the
> yellowish color we see as 'gold.'
>
> Probably not what you were looking for, but now I have
> a problem to play with as I go to sleep tonight ...
> how can one test the individual crystals within a
> glaze to see precisely what they're made of? Or, more
> probable, how to eliminate other possible sources of
> the color in a series of tests that won't require any
> expensive lab equiment I don't have?
>
> Best wishes -- Steve Slatin
>
> --- VeenaRaghavan@CS.COM wrote:
>
>> Hi fellow Clayarters,
>>
>> I am experimenting, which is one of the joys of
>> being a potter. Could someone
>> please tell me what it is that makes a rutile wash
>> go gold on Tenmoku? I want
>> to try and use the same chemical effect but without
>> using the Tenmoku as a
>> glaze. Hope this makes some sense!
>>
>> Thank you in advance for any help
>>
>> Veena
>
>
> Steve Slatin --
>
> Frail my heart apart and play me little Shady Grove
> Ring the bells of Rhymney till they ring inside my head forever
>
> __________________________________________________
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam protection around
> http://mail.yahoo.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 Slatin on sun 31 jul 05
Jane --
First a whopper of a caveat -- this is all
speculation. I need to test several things regarding
rutile overglaze to begin to say I have a good handle
on it. And they don't begin to get into the specifics
of your question, they might just lead me to better
general understanding.
More on topic, I was talking about overglazes --
rutile and a flux (feldspar, frit, whatever). In a
thin overglaze that's 1/2 rutile, the concentration is
way, way higher than in a glaze where it's evenly
mixed. (Ex -- 50/50 overglaze, 85% Ti by
concentration, 42% Ti in overglaze.)
I took a quick look at the base glaze recipe you gave,
and I make it to be (molar concentration follow)
CaO 12.17
MgO 7.5
K+Na 3.59
B2O3 1.10
Al2O3 11.60
SiO2 63.79
Ti, Fe and P, trace only.
I'm not an expert on what makes a glaze, but counting
what most people put 'above the line' and boron
together you have 24.36 fluxes. At ^6, that makes a
melt. You're high on Ca, that tends to lean towards
the satin or matte finish (and Ca glazes often seem to
lean towards opacity). You've got an Si to Al ratio
of 5.5, strongly into the matte range.
If you want visible crystals, you'll probably need to
get more into the glossy range (so the surface can be
seen through), and lessen opacity (so what's suspended
in the glaze becomes visible). Ti itself is an
opacifier, though I've found I can go up to 8% on a
clear glossy glaze and get mostly a clear yellow
effect if I apply it thinly enough.
So ... bear in mind this is complete idle speculation
at this point ... you've got a glaze with a surface
that'll tend to obscure below-the-surface effects and
is slightly opaque by itself, and with 5% titanium (a
known opacifier) and it just 'dulls out.' With less
Ti you have more clarity and you get a Ti yellow.
But you'll have to figure out if it's worth it to you
to test this theory. I use a different high Ca base,
and have a lifetime of experiments dreamed up for it I
haven't tried yet.
Best wishes -- Steve Slatin
--- Jane Murray-Smith wrote:
> So maybe you can tell me why titainium dioxide at 5%
> gave browny grey
> mottled effects, and 2% went pale gold in this base
> glaze from Tony Hansens
> Digital Fire site...(I was trying for little cream
> crystals!)..or is it just
> a matter of cooling slower....
>
> WOLLASTONITE 5.50
> CUSTER SPAR 28.50
> EPK 28.00
> SILICA 15.00
> DOLOMITE 19.00
> GERSTLEY BORATE 4.00
>
> I could send a photo...
> Thanks
> Jane
> ----- Original Message -----
> From: "Steve Slatin"
> To:
> Sent: Saturday, July 30, 2005 11:33 PM
> Subject: Re: Gold color from rutile on Tenmoku
>
>
> > Veena --
> >
> > At cone 6 and in oxidation, rutile makes nearly
> > everything go gold -- you just need to get the
> > concentration right. (I find equal weights rutile
> and
> > frit 3134 makes a great gold over a glossy finish,
> but
> > a dull note over a matte. I intend to try 35/65
> for
> > matte glazes, and experiment from there, but
> haven't
> > gotten around to it yet.) What makes it happen is
> a
> > bit more difficult, but I'd note the following
> things
> > --
> >
> > 1 - rutile is largely titanium, which makes a
> clear
> > glaze go yellow, until you use too much and it
> then
> > becomes an opacifier. In fact, in concentrations
> that
> > make a thin covering go yellow in the glaze, a
> thick
> > application will sometimes go quite white. (rutile
> > starts out as tetragonal crystals) Some rutile
> > minerals are naturally yellow (sphene, for
> example,
> > can be yellow or green), so it appears to be a
> natural
> > color for Ti.
> >
> > 2 -- the second most prevalent element in rutile
> is
> > iron, which makes most things go brown in
> oxidation
> > below cone 10. Iron sulfide, (FeS2),
> interestingly,
> > is 'fools gold.' The iron and sulpher (which has
> a
> > native color of yellow) in this tight crystalline
> form
> > become gold in color. (the crystals are isometric
> > ) The crystals
> can
> > be extremely regular.
> >
> > 3 -- If you look with a loupe or other magnifier
> at
> > the gold parts of a rutile wash on your glaze,
> you'll
> > see a magnificent series of crystals apparently
> > forming within the glaze. Each visible surface
> seems
> > quite square, as would be expected of an isometric
> > crystal.
> >
> > Now, some may condemn me for trying to conduct
> science
> > in a public forum. But points 1 and 2 are well-
> > established, and point 3 is something you can
> confirm
> > yourself. I'm going to say, in answer to your
> > question "what makes it go gold" that a good
> > hypothesis would be that the Ti and/or Fe are
> forming
> > tiny isometric crystals within the glaze at or
> near
> > its vitrification temperature, and are suspended
> > inside of the cooling glaze, where their perfectly
> > formed, smooth, flat surfaces reflect brightly the
> > yellowish color we see as 'gold.'
> >
> > Probably not what you were looking for, but now I
> have
> > a problem to play with as I go to sleep tonight
> ...
> > how can one test the individual crystals within a
> > glaze to see precisely what they're made of? Or,
> more
> > probable, how to eliminate other possible sources
> of
> > the color in a series of tests that won't require
> any
> > expensive lab equiment I don't have?
> >
> > Best wishes -- Steve Slatin
> >
> > --- VeenaRaghavan@CS.COM wrote:
> >
> >> Hi fellow Clayarters,
> >>
> >> I am experimenting, which is one of the joys of
> >> being a potter. Could someone
> >> please tell me what it is that makes a rutile
> wash
> >> go gold on Tenmoku? I want
> >> to try and use the same chemical effect but
> without
> >> using the Tenmoku as a
> >> glaze. Hope this makes some sense!
> >>
> >> Thank you in advance for any help
> >>
> >> Veena
> >
> >
> > Steve Slatin --
> >
> > Frail my heart apart and play me little Shady
> Grove
> > Ring the bells of Rhymney till they ring inside my
> head forever
> >
> > __________________________________________________
> > Do You Yahoo!?
> > Tired of spam? Yahoo! Mail has the best spam
> protection around
> > http://mail.yahoo.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.
> >
>
>
______________________________________________________________________________
> 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 Slatin --
Frail my heart apart and play me little Shady Grove
Ring the bells of Rhymney till they ring inside my head forever
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
Rick Bonomo on mon 1 aug 05
No discussion of rutile decoration would be complete without =
acknowledging the work of Lynn Lais, who decorates with rutile and iron =
oxide on Tenmoku with elegant results:
Click here: =
http://ricks-bricks.com/images/SW%20Lynn%20Lais%20Platter%2015.5w.jpg
and here: http://www.spruceforest.org/artisans/lynnlias/lynnlias.html
Rick Bonomo
agita@shol.com
| |
|
