Paul Lewing on thu 24 apr 03
on 4/24/03 7:07 AM, Lois at sharpe.pots@GTE.NET wrote:
> Also, as I change the % of copper carb should I change the % of titanium?
> I know titanium makes the copper blue, but if I use 1% copper should I lower
> the titanium also? Any one know stats on the color response of titanium to
> copper?
I'm always a little mystified by questions like this. Obviously, if you
change the amounts of any of the colorants in a glaze, it will change the
fired color. Changing the amount makes a change, as does the ratio of
colorants.
So what should the amount of the ratio of colorants be? Who knows? Would
anyone ask, "What color should a car be?", or "What color of shirt is
best?". Test all the amounts, and all the proportions, and decide which one
you like best.
In fact, I'd say pretty much the same about the base recipe, or any base
recipe. Within certain broad parameters, there's no "right" recipe, or no
"right" amount of any ingredient. It's art- the point is to make it look
like what you want.
Paul Lewing,, Seattle
Lois on thu 24 apr 03
This glaze is from Val Cushing's hand book. Copper Aqua Cone 10 reduction.
I fire a flat 10.
Feldspar-(custer) 51.0
Silica 21.0
Whiting-(vicron) 13.0
Gerstley borate 6.0
Soda ash 4.0
Barium carb 4.0
Lithium carb 1.0
Add
Titanium 4.0%
Copper carb 1-5%
Bentonite 2.0%
It is very very RUNNY and I would like to cut back on some flux. But am
worried if I take the soda ash or lithium out I will loose the color.
Any ideas on where to start?
Also, as I change the % of copper carb should I change the % of titanium?
I know titanium makes the copper blue, but if I use 1% copper should I lower
the titanium also? Any one know stats on the color response of titanium to
copper?
Thanks In advance!
Lois Sharpe
In Durham NC
Not limping anymore! with a brand new "bionic" knee!
Tom Fossier on thu 24 apr 03
Lois,
The balance of fluxes used in a glaze will have considerable impact on the
color, so rather than removing a flux and changing this balance, I would
recommend adding some kaolin to this recipe. I would do a line blend: make a
small bucket of the existing recipe and make another small bucket of the
recipe plus 25% kaolin. Place several paper cups in a row between the
buckets, and using a measuring cup or any small measuring device,
volumetrically blend the two glazes in the cups. The first cup, for example
might be 90% glaze 1 and 10% glaze 2; the second cup 80% - 20%, and so on.
Dip or pour on your test tiles or test bowls and see how they do in your
next firing (be sure to put something under these tests to catch glaze
runoff from the runnier tiles, and, of course, mark your test pieces with
some kind of ID).
What you will have essentially done is to make a family of related glazes
from one recipe, and it is very likely that one of these will be stiff
enough and yet retain the color that you desire. Since you will know which
cup your favorite test was glazed from, you will know how much kaolin was
added to the glaze recipe in that particular test.
Alumina is what stiffens melted glazes and keeps them from running off the
pot. Alumina hydrate, however, doesn't incorporate very well in many glazes,
resulting in a rough texture. That is why kaolin is usually used to stiffen
glazes.
It is possible that part of the appeal of the glaze is due to the formation
of colorful crystals, and the stiffer the glaze, the fewer crystals will
form (the movement of a runny glaze is a mechanism which allows the
crystal-forming molecules to find each other). I would expect that your line
blend will lose some of its crystals and color at the stiffer end of the
line.
I believe that the titanium in the glaze is primarily a crystal-former, and
that the blue response of the copper is due to the alkaline quality of the
fluxes. Both barium and lithium are alkaline fluxes.
I hope this helps,
Tom Fossier
----------
>From: Lois
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Glaze help!
>Date: Thu, Apr 24, 2003, 8:07 AM
>
> This glaze is from Val Cushing's hand book. Copper Aqua Cone 10 reduction.
> I fire a flat 10.
>
>
> Feldspar-(custer) 51.0
> Silica 21.0
> Whiting-(vicron) 13.0
> Gerstley borate 6.0
> Soda ash 4.0
> Barium carb 4.0
> Lithium carb 1.0
>
> Add
>
> Titanium 4.0%
> Copper carb 1-5%
> Bentonite 2.0%
>
>
> It is very very RUNNY and I would like to cut back on some flux. But am
> worried if I take the soda ash or lithium out I will loose the color.
>
> Any ideas on where to start?
>
>
> Also, as I change the % of copper carb should I change the % of titanium?
> I know titanium makes the copper blue, but if I use 1% copper should I lower
> the titanium also? Any one know stats on the color response of titanium to
> copper?
>
> Thanks In advance!
>
> Lois Sharpe
> In Durham NC
> Not limping anymore! with a brand new "bionic" knee!
>
> ______________________________________________________________________________
> 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.
>
Lily Krakowski on thu 24 apr 03
I know next to 0 about c10 reduction. But I would cut back on the spar,
replacing it with kaolin. When I had that right I would add silica because
feldspar has 6 silica to one alumina and clay 1 to 2.
But, unless this thing is really runny, my first step would be to replace
the titanium with tin, as tin is more refractory. I had never heard of
titanium helping copper blues, though Cooper mention titanium going bluish
at high temps.
Lois writes:
> This glaze is from Val Cushing's hand book. Copper Aqua Cone 10 reduction.
> I fire a flat 10.
>
>
> Feldspar-(custer) 51.0
> Silica 21.0
> Whiting-(vicron) 13.0
> Gerstley borate 6.0
> Soda ash 4.0
> Barium carb 4.0
> Lithium carb 1.0
>
> Add
>
> Titanium 4.0%
> Copper carb 1-5%
> Bentonite 2.0%
>
>
> It is very very RUNNY and I would like to cut back on some flux. But am
> worried if I take the soda ash or lithium out I will loose the color.
>
> Any ideas on where to start?
>
>
> Also, as I change the % of copper carb should I change the % of titanium?
> I know titanium makes the copper blue, but if I use 1% copper should I lower
> the titanium also? Any one know stats on the color response of titanium to
> copper?
>
> Thanks In advance!
>
> Lois Sharpe
> In Durham NC
> Not limping anymore! with a brand new "bionic" knee!
>
> ______________________________________________________________________________
> 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.
Lili Krakowski
P.O. Box #1
Constableville, N.Y.
(315) 942-5916/ 397-2389
Be of good courage....
Fraser Forsythe on thu 24 apr 03
Hi Lois.
Alkaline materials in a recipe influence copper, not
titanium. I dont think tiO2 has that affect, although
it can alter colour quite a lot - especally cobalt -
if percentages are high enough.
I ran your glaze through my program and it came out as
a cone 7-9 glaze. It has high expansion (crazes
right?) and low viscosity and surface tension. After
playing around with it I would recommend just
increasing your silica content from 21 to 26 or 27.
This will do a few things: decrease expansion
(although it will probably still craze), increase
firing range toward cone 10, and increase both
viscosity and surface tension. If you had a clay in
the formula that would probably be the most direct
lever to adjust to increase firing range and stiffen
the glaze. Increasing silica and leaving everything
else alone with do.
Lithium, soda ash, gerstley and the feldspar provide
the alkaline content. You could probably get away
without the lithium, since it's such a low percentage
anyway. I like recipes with less rather than more.
Your decision.
When I removed the gerstley the firing range increased
a lot but the expansion stayed very high.
So, again, increasing the silica is probably the best
(and as it turns out easiest) method to fix up this
recipe.
Fraser
--- Lois wrote: > This glaze is
from Val Cushing's hand book. Copper
> Aqua Cone 10 reduction.
> I fire a flat 10.
>
>
> Feldspar-(custer) 51.0
> Silica 21.0
> Whiting-(vicron) 13.0
> Gerstley borate 6.0
> Soda ash 4.0
> Barium carb 4.0
> Lithium carb 1.0
>
> Add
>
> Titanium 4.0%
> Copper carb 1-5%
> Bentonite 2.0%
>
>
> It is very very RUNNY and I would like to cut back
> on some flux. But am
> worried if I take the soda ash or lithium out I will
> loose the color.
>
> Any ideas on where to start?
>
>
> Also, as I change the % of copper carb should I
> change the % of titanium?
> I know titanium makes the copper blue, but if I use
> 1% copper should I lower
> the titanium also? Any one know stats on the color
> response of titanium to
> copper?
>
> Thanks In advance!
>
> Lois Sharpe
> In Durham NC
> Not limping anymore! with a brand new "bionic"
> knee!
>
>
______________________________________________________________________________
> 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.
=====
Fraser Forsythe
fraser@glazeexchange.com
Guelph,Canada
______________________________________________________________________
Post your free ad now! http://personals.yahoo.ca
Tony Hansen on thu 24 apr 03
You might also consider blending with a mixture of
2 parts silica to 1 part kaolin. This mix has the
same silica:alumina ratio as the glaze and will have
the minimum impact on visual character.
> Lois,
> The balance of fluxes used in a glaze will have considerable impact on the
> color, so rather than removing a flux and changing this balance, I would
> recommend adding some kaolin to this recipe. I would do a line blend: make a
> small bucket of the existing recipe and make another small bucket of the
> recipe plus 25% kaolin. Place several paper cups in a row between the
> buckets, and using a measuring cup or any small measuring device,
> volumetrically blend the two glazes in the cups. The first cup, for example
> might be 90% glaze 1 and 10% glaze 2; the second cup 80% - 20%, and so on.
> Dip or pour on your test tiles or test bowls and see how they do in your
> next firing (be sure to put something under these tests to catch glaze
> runoff from the runnier tiles, and, of course, mark your test pieces with
> some kind of ID).
> What you will have essentially done is to make a family of related glazes
> from one recipe, and it is very likely that one of these will be stiff
> enough and yet retain the color that you desire. Since you will know which
> cup your favorite test was glazed from, you will know how much kaolin was
> added to the glaze recipe in that particular test.
> Alumina is what stiffens melted glazes and keeps them from running off the
> pot. Alumina hydrate, however, doesn\'t incorporate very well in many glazes,
> resulting in a rough texture. That is why kaolin is usually used to stiffen
> glazes.
> It is possible that part of the appeal of the glaze is due to the formation
> of colorful crystals, and the stiffer the glaze, the fewer crystals will
> form (the movement of a runny glaze is a mechanism which allows the
> crystal-forming molecules to find each other). I would expect that your line
> blend will lose some of its crystals and color at the stiffer end of the
> line.
> I believe that the titanium in the glaze is primarily a crystal-former, and
> that the blue response of the copper is due to the alkaline quality of the
> fluxes. Both barium and lithium are alkaline fluxes.
> I hope this helps,
> Tom Fossier
> >
> > Feldspar-(custer) 51.0
> > Silica 21.0
> > Whiting-(vicron) 13.0
> > Gerstley borate 6.0
> > Soda ash 4.0
> > Barium carb 4.0
> > Lithium carb 1.0
> >
> > Add
> >
> > Titanium 4.0%
> > Copper carb 1-5%
> > Bentonite 2.0%
> >
______________________________________________________________________________
========
Tony Hansen
william schran on thu 24 apr 03
Lois - Well for one thing, there ain't no clay in this glaze, Except
for the little bit of bentonite for suspension. Might want to simply
try removing the gerstley borate and run test of adding EPK or ball
clay in 5% increments.
Bill
>This glaze is from Val Cushing's hand book. Copper Aqua Cone 10 reduction.
>I fire a flat 10.
>
>
>Feldspar-(custer) 51.0
>Silica 21.0
>Whiting-(vicron) 13.0
>Gerstley borate 6.0
>Soda ash 4.0
>Barium carb 4.0
>Lithium carb 1.0
>
>Add
>
>Titanium 4.0%
>Copper carb 1-5%
>Bentonite 2.0%
>
>
>It is very very RUNNY and I would like to cut back on some flux. But am
>worried if I take the soda ash or lithium out I will loose the color.
>
>Any ideas on where to start?
>
>
>Also, as I change the % of copper carb should I change the % of titanium?
>I know titanium makes the copper blue, but if I use 1% copper should I lower
>the titanium also? Any one know stats on the color response of titanium to
>copper?
>
>Thanks In advance!
>
>Lois Sharpe
>In Durham NC
>Not limping anymore! with a brand new "bionic" knee!
>
>______________________________________________________________________________
>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.
Lily Krakowski on fri 25 apr 03
Bless you, Paul. But let me help you: cars--black; pickups--light blue;
shirts--pink.
Paul Lewing writes:
> on 4/24/03 7:07 AM, Lois at sharpe.pots@GTE.NET wrote:
>
>> Also, as I change the % of copper carb should I change the % of titanium?
>> I know titanium makes the copper blue, but if I use 1% copper should I lower
>> the titanium also? Any one know stats on the color response of titanium to
>> copper?
>
> I'm always a little mystified by questions like this. Obviously, if you
> change the amounts of any of the colorants in a glaze, it will change the
> fired color. Changing the amount makes a change, as does the ratio of
> colorants.
> So what should the amount of the ratio of colorants be? Who knows? Would
> anyone ask, "What color should a car be?", or "What color of shirt is
> best?". Test all the amounts, and all the proportions, and decide which one
> you like best.
> In fact, I'd say pretty much the same about the base recipe, or any base
> recipe. Within certain broad parameters, there's no "right" recipe, or no
> "right" amount of any ingredient. It's art- the point is to make it look
> like what you want.
> Paul Lewing,, Seattle
>
> ______________________________________________________________________________
> 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.
Lili Krakowski
P.O. Box #1
Constableville, N.Y.
(315) 942-5916/ 397-2389
Be of good courage....
Ron Roy on sun 27 apr 03
Hi Lois,
This is a high alkaline glaze and will produce that typical kind of
turquoise colour if not too much alumina is present. The alkaline fluxes
(K2O, Na2O and Li2O) promote running. Alumina retards running. The
expansion is high so it will craze - so you see these types of glazes are
difficult to use. I have reformulated it with Ferro frit 3278 so there is
more raw clay in it to help the settling problem and have added some silica
to help stop the running - best to keep the application as thin as possible
for the result you like. Pots can be designed to help stop running -
trimming little "dams" near the bottom that will help stop the running.
Feet can be designed not to show much and the glaze will therefore not be
as close to the shelf.
Don't forget to add the Bentonite, TiO2and Copper carb in. Be sure to give
this the lemon test - high alkaline glazes - especially the sodium promotes
leaching and there are toxic materials in this. Copper can also change the
taste of foods if enough gets in.
Custer - 35.5
Whiting - 13.0
Frit 3278 - 7.0
Soda ash - 4.0
Barium Carb - 4.0
Lithium Carb - 1.0
EPK - 8.5
Silica - 27.0
Total - 100.0
It will still craze so I have also removed the Barium to get it a bit lower
in this next one. You might find the colour still acceptable.
Custer - 35.5
Whiting - 15.0
Frit 3278 - 7.0
Soda ash - 4.0
Lithium Carb - 1.0
EPK - 8.5
Silica - 29.0
Total - 100.0
I think it will still craze but that is the nature if this kind of glaze.
Let me know the results and I may be able to make some improvements
RR
>> This glaze is from Val Cushing's hand book. Copper Aqua Cone 10 reduction.
>> I fire a flat 10.
>>
>>
>> Feldspar-(custer) 51.0
>> Silica 21.0
>> Whiting-(vicron) 13.0
>> Gerstley borate 6.0
>> Soda ash 4.0
>> Barium carb 4.0
>> Lithium carb 1.0
>>
>> Add
>>
>> Titanium 4.0%
>> Copper carb 1-5%
>> Bentonite 2.0%
>>
>>
>> It is very very RUNNY and I would like to cut back on some flux. But am
>> worried if I take the soda ash or lithium out I will loose the color.
>>
>> Any ideas on where to start?
>>
>>
>> Also, as I change the % of copper carb should I change the % of titanium?
>> I know titanium makes the copper blue, but if I use 1% copper should I lower
>> the titanium also? Any one know stats on the color response of titanium to
>> copper?
>>
>> Thanks In advance!
>>
>> Lois Sharpe
>> In Durham NC
>> Not limping anymore! with a brand new "bionic" knee!
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Lois on sun 27 apr 03
THANK YOU!
I have much testing to do! I certainly appreciate all the information and
the re-working of this. I will let you know how it turns out.
Ever so grateful,
lois
On 4/27/03 11:55 AM, "Ron Roy" wrote:
> Hi Lois,
>
> This is a high alkaline glaze and will produce that typical kind of
> turquoise colour if not too much alumina is present. The alkaline fluxes
> (K2O, Na2O and Li2O) promote running. Alumina retards running. The
> expansion is high so it will craze - so you see these types of glazes are
> difficult to use. I have reformulated it with Ferro frit 3278 so there is
> more raw clay in it to help the settling problem and have added some silica
> to help stop the running - best to keep the application as thin as possible
> for the result you like. Pots can be designed to help stop running -
> trimming little "dams" near the bottom that will help stop the running.
> Feet can be designed not to show much and the glaze will therefore not be
> as close to the shelf.
>
> Don't forget to add the Bentonite, TiO2and Copper carb in. Be sure to give
> this the lemon test - high alkaline glazes - especially the sodium promotes
> leaching and there are toxic materials in this. Copper can also change the
> taste of foods if enough gets in.
>
> Custer - 35.5
> Whiting - 13.0
> Frit 3278 - 7.0
> Soda ash - 4.0
> Barium Carb - 4.0
> Lithium Carb - 1.0
> EPK - 8.5
> Silica - 27.0
> Total - 100.0
>
> It will still craze so I have also removed the Barium to get it a bit lower
> in this next one. You might find the colour still acceptable.
>
> Custer - 35.5
> Whiting - 15.0
> Frit 3278 - 7.0
> Soda ash - 4.0
> Lithium Carb - 1.0
> EPK - 8.5
> Silica - 29.0
> Total - 100.0
>
> I think it will still craze but that is the nature if this kind of glaze.
>
> Let me know the results and I may be able to make some improvements
>
> RR
>
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