Judy Smith on sat 29 aug 09
I have a cone 9 oxidation base glaze that I need converted to cone 6. If I
buy a glaze calculation program, will it convert the glaze for me? Here is
the formula.
nepheline syenite 36
whiting 9
barium carbonate 9
frit 4113 9
talc 4
silica 28
kaolin 5
Thanks,
Judy Smith
Nashville, TN
Paul Lewing on sun 30 aug 09
On Aug 30, 2009, at 1:00 PM, The Fuzzy Chef wrote:
On 8/29/09 8:45 PM, Judy Smith wrote:
> I have a cone 9 oxidation base glaze that I need converted to cone
> 6. If I
> buy a glaze calculation program, will it convert the glaze for me?
> Here is
> the formula.
Short answer: no.
The Fuzzy Chef is right on there. Calculation programs do not tell
you at what cone a glaze will melt. Mostly because many glazes have a
wide range and also the firing and cooling cycles have much to do with
the surface, and they know nothing about that.
About 23 years ago I made that switch too. It was before calculation
programs and I didn't know enough about the Seger method to do it that
way. I also made the switch from reduction to oxidation at that time
and I found that to be a bigger change. You're lucky you're not
making that switch.
Matte glazes are especially hard to convert that far because typically
you take out both alumina and silica and leave the flux balance alone
if you want to maintain the same characteristics. Well, often even
taking all of the alumina and silica out of a cone 9 glaze will not
drop it far enough. Usually you have to either substitute more active
fluxes for less active ones and that changes color responses. Or you
have to add boron, which also changes color responses.
If you want to try this with a calculation program, here's what you
do. Keep the fluxes exactly the same, in the same proportions. Lower
both the alumina and the silica in ratios that will keep the Al/Si
ratio the same. A set of limit formulas will help in this. If, let's
say, your Al is at the top of the allowable range for cone 9, drop it
down to about the top of the allowable range for cone 6, and the same
with the silica. If the Si is in the low end, or the middle, of the
range for cone 9, put it at the same position in the limits for cone
6. It might work, it might not.
The only glazes I got to work at cone 5 from cone 10 (a bigger jump
than you're making) were achieved by what I call the TIFTIM method.
That stands for Throw In Frit Till It Melts. My best success was
taking cone 10 Shaner's Clear and making a clear at cone 5 that I call
SC40F. If you add 40 grams of frit 3134 to Shaner's Clear, and make
that 140 gram batch add up to 100, you get the recipe for SC40F
(Shaner Clear + 40 Frit). It's essentially adding boron and no alumina.
Paul Lewing
www.paullewingtile.com
www.paullewingart.com
The Fuzzy Chef on sun 30 aug 09
On 8/29/09 8:45 PM, Judy Smith wrote:
> I have a cone 9 oxidation base glaze that I need converted to cone 6. If=
I
> buy a glaze calculation program, will it convert the glaze for me? Here =
is
> the formula.
Short answer: no.
Really, two years ago I went from Cone 9 to Cone 6. Even with my glaze
calculation formulae, I had zero successes out of 6 glazes in "cooling"
them. While I was able to make the glazes fit and gloss correctly at 6
(some of the time), the changes in base ingredients always affected the
colors in undesirable ways.
I recommend instead developing new glazes for Cone 6, possibly based on
the colorants you were using at Cone 9. Mastering Cone 6 Glazes is an
excellent guide.
--Josh Berkus
June on mon 31 aug 09
Have you tested this glaze at cone 6? I ran the formula through my Insight =
software and it's well within the limits of Cone 6 copper bearing glazes wh=
ich call for higher amounts of alumina and silica, so you might be surprise=
d to find that it works at cone 6
Regards,
June
http://www.shambhalapottery.blogspot.com
http://www.shambhalapottery.com
http://groups.yahoo.com/group/sodasaltfiring/
http://saltandsodafiring.ning.com/
http://ncclayclub.blogspot.com
________________________________
From: Paul Lewing
To: Clayart@LSV.CERAMICS.ORG
Sent: Sunday, August 30, 2009 11:29:44 PM
Subject: Re: converting glaze from cone 9 to cone 6
On Aug 30, 2009, at 1:00 PM, The Fuzzy Chef wrote:
On 8/29/09 8:45 PM, Judy Smith wrote:
> I have a cone 9 oxidation base glaze that I need converted to cone
> 6. If I
> buy a glaze calculation program, will it convert the glaze for me?
> Here is
> the formula.
Short answer: no.
The Fuzzy Chef is right on there. Calculation programs do not tell
you at what cone a glaze will melt. Mostly because many glazes have a
wide range and also the firing and cooling cycles have much to do with
the surface, and they know nothing about that.
About 23 years ago I made that switch too. It was before calculation
programs and I didn't know enough about the Seger method to do it that
way. I also made the switch from reduction to oxidation at that time
and I found that to be a bigger change. You're lucky you're not
making that switch.
Matte glazes are especially hard to convert that far because typically
you take out both alumina and silica and leave the flux balance alone
if you want to maintain the same characteristics. Well, often even
taking all of the alumina and silica out of a cone 9 glaze will not
drop it far enough. Usually you have to either substitute more active
fluxes for less active ones and that changes color responses. Or you
have to add boron, which also changes color responses.
If you want to try this with a calculation program, here's what you
do. Keep the fluxes exactly the same, in the same proportions. Lower
both the alumina and the silica in ratios that will keep the Al/Si
ratio the same. A set of limit formulas will help in this. If, let's
say, your Al is at the top of the allowable range for cone 9, drop it
down to about the top of the allowable range for cone 6, and the same
with the silica. If the Si is in the low end, or the middle, of the
range for cone 9, put it at the same position in the limits for cone
6. It might work, it might not.
The only glazes I got to work at cone 5 from cone 10 (a bigger jump
than you're making) were achieved by what I call the TIFTIM method.
That stands for Throw In Frit Till It Melts. My best success was
taking cone 10 Shaner's Clear and making a clear at cone 5 that I call
SC40F. If you add 40 grams of frit 3134 to Shaner's Clear, and make
that 140 gram batch add up to 100, you get the recipe for SC40F
(Shaner Clear + 40 Frit). It's essentially adding boron and no alumina.
Paul Lewing
www.paullewingtile.com
www.paullewingart.com
John Hesselberth on mon 31 aug 09
On Aug 30, 2009, at 11:29 PM, Paul Lewing wrote:
> Short answer: no.
> The Fuzzy Chef is right on there.
> If you want to try this with a calculation program, here's what you
> do. Keep the fluxes exactly the same, in the same proportions. Lower
> both the alumina and the silica in ratios that will keep the Al/Si
> ratio the same.
Hi Paul,
I agree with you and Fuzzy Chef that the short answer is "no". In fact
I think converting that far and ending up with the same aesthetics is
nearly impossible--there are probably rare exceptions. But in
developing cone 6 glazes that will be stable and suitable for use on
functional work, I use a very different approach from what you
describe above. To be stable, a glaze has to have enough silica and
alumina and lowering them while keeping the flux the same will just
move the glaze toward an unstable composition. That is probably how so
many unstable cone 6 glazes end up published in the literature.
So, starting with a good stable cone 9 or 10 glaze, I keep the alumina
and silica the same and substitute more active fluxes (including
adding boron or zinc). I decrease the alkaline earths a bit and
increase the alkalis in addition to adding about 0.25 of boron or
zinc. Yes that will probably change the color response, but the
resulting glaze has a much better chance of being good for functional
work. And by carefully choosing your substitutes (e.g. calcium or
strontium for magnesium or barium), you can sometimes come close on
color response.
But the better solution is to start over from good cone 6 bases and
then develop a color palette that works for you.
Regards,
John Hesselberth
www.frogpondpottery.com
"Man is a tool-using animal....without tools he is nothing, with tools
he is all" .... Thomas Carlyle
Steve Slatin on mon 31 aug 09
Paul, you have an interesting point, but=3D20
Judy's problem is more daunting that it
at first seems. Her primary melter source
is nepheline syenite, and she's got quite
a bit of it in the recipe. So she's
really high in sodium, and raising her
melter-source without changing proportions
of melters will leave her with a probably
unfavorable COE. =3D20
Some changes are just hard to make; boron
or lithium will change the color response
and lithium will possibly encourage=3D20
nucleation in the glaze as well ...=3D20
melters like cobalt are also colorants ...
it just doesn't look easy to get to ^6
with that glaze.
Steve Slatin --=3D20
--- On Sun, 8/30/09, Paul Lewing wrote:
=3D20
> Short answer: no.
> The Fuzzy Chef is right on there.=3DA0 Calculation
> programs do not tell
> you at what cone a glaze will melt.=3DA0 Mostly because
> many glazes have a
> wide range and also the firing and cooling cycles have much
> to do with
> the surface, and they know nothing about that.
> About 23 years ago I made that switch too.=3DA0 It was
> before calculation
> programs and I didn't know enough about the Seger method to
> do it that
> way.=3DA0 I also made the switch from reduction to
> oxidation at that time
> and I found that to be a bigger change.=3DA0 You're lucky
> you're not
> making that switch.
> Matte glazes are especially hard to convert that far
> because typically
> you take out both alumina and silica and leave the flux
> balance alone
> if you want to maintain the same characteristics.=3DA0
> Well, often even
> taking all of the alumina and silica out of a cone 9 glaze
> will not
> drop it far enough.=3DA0 Usually you have to either
> substitute more active
> fluxes for less active ones and that changes color
> responses.=3DA0 Or you
> have to add boron, which also changes color responses.
> If you want to try this with a calculation program, here's
> what you
> do.=3DA0 Keep the fluxes exactly the same, in the same
> proportions.=3DA0 Lower
> both the alumina and the silica in ratios that will keep
> the Al/Si
> ratio the same.=3DA0 A set of limit formulas will help in
> this.=3DA0 If, let's
> say, your Al is at the top of the allowable range for cone
> 9, drop it
> down to about the top of the allowable range for cone 6,
> and the same
> with the silica.=3DA0 If the Si is in the low end, or the
> middle, of the
> range for cone 9, put it at the same position in the limits
> for cone
> 6.=3DA0 It might work, it might not.
> The only glazes I got to work at cone 5 from cone 10 (a
> bigger jump
> than you're making) were achieved by what I call the TIFTIM
> method.
> That stands for Throw In Frit Till It Melts.=3DA0 My best
> success was
> taking cone 10 Shaner's Clear and making a clear at cone 5
> that I call
> SC40F.=3DA0 If you add 40 grams of frit 3134 to Shaner's
> Clear, and make
> that 140 gram batch add up to 100, you get the recipe for
> SC40F
> (Shaner Clear + 40 Frit).=3DA0 It's essentially adding
> boron and no alumina.
>=3D20
> Paul Lewing
> www.paullewingtile.com
> www.paullewingart.com
> =3D0A=3D0A=3D0A
Paul Lewing on mon 31 aug 09
On Aug 31, 2009, at 7:55 AM, John Hesselberth wrote
I agree with you and Fuzzy Chef that the short answer is "no". In fact
I think converting that far and ending up with the same aesthetics is
nearly impossible--there are probably rare exceptions.
True. And unless you're really proficient with a calculation program,
it's probably best to stick with that short answer. I can tell you
pretty well with a program what cone a glaze will fire to, but it
takes looking at a few thousand formulas to do that.
I use a very different approach from what you describe above.
So, starting with a good stable cone 9 or 10 glaze, I keep the alumina
and silica the same and substitute more active fluxes (including
adding boron or zinc).
If you just substitute one molecule of a more active flux for a less
active one, you are keeping the alumina and silica the same. But as
soon as you start adding molecules of other substances, you are in
effect lowering the alumina and silica. You don't necessarily see
that in a Seger analysis because it keeps the fluxes at 1 and usually
puts the boron into a classification that affects neither the flux
column nor the alumina, but if you look at the same formula as a
percentage analysis, you'll see it.
Paul Lewing
www.paullewingtile.com
www.paullewingart.com
Chaeli Sullivan on tue 1 sep 09
Hi Judy
I agree with June that the appearance of this=3DA0glaze's ingredients=3DA0g=
ives=3D
every indication that it will work at Cone 6.=3DA0=3D20
Could you run some test tiles?
Chae
--- On Mon, 8/31/09, June wrote:
From: June
Subject: Re: converting glaze from cone 9 to cone 6
To: Clayart@LSV.CERAMICS.ORG
Date: Monday, August 31, 2009, 5:55 AM
Have you tested this glaze at cone 6? I ran the formula through my Insight =
=3D
software and it's well within the limits of Cone 6 copper bearing glazes wh=
=3D
ich call for higher amounts of alumina and silica, so you might be surprise=
=3D
d to find that it works at cone 6
Regards,
June
http://www.shambhalapottery.blogspot.com
http://www.shambhalapottery.com
http://groups.yahoo.com/group/sodasaltfiring/
http://saltandsodafiring.ning.com/
http://ncclayclub.blogspot.com
________________________________
From: Paul Lewing
To: Clayart@LSV.CERAMICS.ORG
Sent: Sunday, August 30, 2009 11:29:44 PM
Subject: Re: converting glaze from cone 9 to cone 6
On Aug 30, 2009, at 1:00 PM, The Fuzzy Chef wrote:
On 8/29/09 8:45 PM, Judy Smith wrote:
> I have a cone 9 oxidation base glaze that I need converted to cone
> 6.=3DA0 If I
> buy a glaze calculation program, will it convert the glaze for me?
> Here is
> the formula.
Short answer: no.
The Fuzzy Chef is right on there.=3DA0 Calculation programs do not tell
you at what cone a glaze will melt.=3DA0 Mostly because many glazes have a
wide range and also the firing and cooling cycles have much to do with
the surface, and they know nothing about that.
About 23 years ago I made that switch too.=3DA0 It was before calculation
programs and I didn't know enough about the Seger method to do it that
way.=3DA0 I also made the switch from reduction to oxidation at that time
and I found that to be a bigger change.=3DA0 You're lucky you're not
making that switch.
Matte glazes are especially hard to convert that far because typically
you take out both alumina and silica and leave the flux balance alone
if you want to maintain the same characteristics.=3DA0 Well, often even
taking all of the alumina and silica out of a cone 9 glaze will not
drop it far enough.=3DA0 Usually you have to either substitute more active
fluxes for less active ones and that changes color responses.=3DA0 Or you
have to add boron, which also changes color responses.
If you want to try this with a calculation program, here's what you
do.=3DA0 Keep the fluxes exactly the same, in the same proportions.=3DA0 Lo=
wer
both the alumina and the silica in ratios that will keep the Al/Si
ratio the same.=3DA0 A set of limit formulas will help in this.=3DA0 If, le=
t's
say, your Al is at the top of the allowable range for cone 9, drop it
down to about the top of the allowable range for cone 6, and the same
with the silica.=3DA0 If the Si is in the low end, or the middle, of the
range for cone 9, put it at the same position in the limits for cone
6.=3DA0 It might work, it might not.
The only glazes I got to work at cone 5 from cone 10 (a bigger jump
than you're making) were achieved by what I call the TIFTIM method.
That stands for Throw In Frit Till It Melts.=3DA0 My best success was
taking cone 10 Shaner's Clear and making a clear at cone 5 that I call
SC40F.=3DA0 If you add 40 grams of frit 3134 to Shaner's Clear, and make
that 140 gram batch add up to 100, you get the recipe for SC40F
(Shaner Clear + 40 Frit).=3DA0 It's essentially adding boron and no alumina=
.
Paul Lewing
www.paullewingtile.com
www.paullewingart.com
=3D0A=3D0A=3D0A
Ron Roy on sat 5 sep 09
Hi Judy,
No it will not - but it will be a great help if you take the time to learn
how to use it..
In the meantime - if you send me the analysis for frit 4113 I will have a g=
o
at lowering it to cone 6 - tell me what colorants you use with this glaze
and also if you use it as a liner glaze.
RR
On Sat, Aug 29, 2009 at 11:45 PM, Judy Smith wrote:
> I have a cone 9 oxidation base glaze that I need converted to cone 6. If=
I
> buy a glaze calculation program, will it convert the glaze for me? Here =
is
> the formula.
> nepheline syenite 36
> whiting 9
> barium carbonate 9
> frit 4113 9
> talc 4
> silica 28
> kaolin 5
>
> Thanks,
> Judy Smith
> Nashville, TN
>
--
Ron Roy
15084 Little Lake Road
Brighton, Ontario, Canada
K0K 1H0
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