Linco Schoenne on fri 9 oct 98
I just recently tried alpine white clay. No problem with the clay - but
of the several glazes I have tried on it - none were appealing.
Christmas sale is coming fast and I am running out of time. Would anyone
have a recipe they would like to share? I am hoping for a satin white
^6 glaze, or a good clear base glase.
I also wonder if anyone has a recipe for copper matt lustre? (Raku)
Any help will be appreciated.
Linco schoenne
lincoschoenne@hotmail.com
______________________________________________________
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June Perry on sun 11 oct 98
Copper Matt
90 Copper oxide
10 Ferro Frit 3110
You can also try a variation with maybe an addition of 3-5% red iron oxide,
etc.
Also try 80 copper 20 frit.
Hank Ray on mon 12 oct 98
Hello ...
Here is a cone 6 satin glaze... that is durable and food safe base when used
reasonably with colorants.... that of coure is my disclaimer.... for a white
you can add an opacifier.... 4or5 % tin or 8 or so % zircopax
Saturday base cone 6 satin glaze
dolomite..............19
whiting..................3
custer felsdspar....35
om#4(ball clay).....19
flint......................19
Peter...
in the great state of oklahoma...
In a message dated 98-10-09 09:16:58 EDT, you write:
<< I am hoping for a satin white
^6 glaze, or a good clear base glase.
I also wonder if anyone has a recipe for copper matt lustre? (Raku)
Any help will be appreciated.
Linco schoenne
lincoschoenne@hotmail.com
>>
+
Alison Hamilton on tue 13 oct 98
I find this glaze to be really easy to work with (it's forgiving, thus
great for a school studio environment) and it's a nice satiny matt
white, depending on how high you fire it.
Tim's White (cone 6-8, oxidation)
Custer feldspar 15.75
Colemanite 4.5
Dolemanite 6.75
Talc 4.5
Whiting 2.25
Kaolin 6.75
Hope this helps. And belated Happy Thanksgiving to all the Canucks out
there!
Alison Hamilton
Dorset, ON
Flint 4.5
Zircopax 3.4
plus 2% bentonite
CLAYART@LSV.UKY.EDU wrote:
>
> ----------------------------Original message----------------------------
> I just recently tried alpine white clay. No problem with the clay - but
> of the several glazes I have tried on it - none were appealing.
> Christmas sale is coming fast and I am running out of time. Would anyone
> have a recipe they would like to share? I am hoping for a satin white
> ^6 glaze, or a good clear base glase.
>
> I also wonder if anyone has a recipe for copper matt lustre? (Raku)
>
> Any help will be appreciated.
>
> Linco schoenne
> lincoschoenne@hotmail.com
>
> ______________________________________________________
> Get Your Private, Free Email at http://www.hotmail.com
Ron Roy on wed 14 oct 98
This glaze doesn't look like it will melt at cone 6 and the total is only
95 - could there have been something left out - like 5% G. Borate? If that
is the case I would agree it is probably food safe - with reasonable
amounts of stain or oxide. Just keep in mind - the amount of any oxide that
can be held in solution in a glaze varies with each oxide - the Hamer book
give some guidelines in this area.
>Here is a cone 6 satin glaze... that is durable and food safe base when used
>reasonably with colorants.... that of coure is my disclaimer.... for a white
>you can add an opacifier.... 4or5 % tin or 8 or so % zircopax
>
>Saturday base cone 6 satin glaze
>dolomite..............19
>whiting..................3
>custer felsdspar....35
>om#4(ball clay).....19
>flint......................19
Ron Roy
93 Pegasus Trail
Scarborough, Ontario
Canada M1G 3N8
Tel: 416-439-2621
Fax: 416-438-7849
Web page: http://digitalfire.com/education/people/ronroy.htm
Ron Roy on thu 15 oct 98
This glaze is under supplied with silica and over supplied with MgO when I
compare it with the limits I use to assess durability - I do not think it
poses any great risk - unless any toxics are added to it.
I am again wondering if I am playing with a full deck - the total is 50.40.
I have used 1 bentonite, EPK as the kaolin, gerstley borate not colemanite.
I also made zircopax a phantom material so that the SiO2 in it would not be
included as available to the glass.
In order for it to have enough SiO2 to match up with the limits I use you
would have to add 8.0 silica - new total would be 57.40 - it would not be
the same looking glaze - just trying to give some idea of just how short it
is of SiO2.
Anybody else come to the same conclusion?
>----------------------------Original message----------------------------
>I find this glaze to be really easy to work with (it's forgiving, thus
>great for a school studio environment) and it's a nice satiny matt
>white, depending on how high you fire it.
>
>Tim's White (cone 6-8, oxidation)
>
>Custer feldspar 15.75
>Colemanite 4.5
>Dolemanite 6.75
>Talc 4.5
>Whiting 2.25
>Kaolin 6.75
>Flint 4.5
>Zircopax 3.4
>plus 2% bentonite
Ron Roy
93 Pegasus Trail
Scarborough, Ontario
Canada M1G 3N8
Tel: 416-439-2621
Fax: 416-438-7849
Web page: http://digitalfire.com/education/people/ronroy.htm
Alison Hamilton on sun 18 oct 98
Drats!
Wouldn't you know the first time I post a glaze recipe I'm caught like
the proverbial deer in the headlights! And while I wouldn't want to be
the one to comment on whether Ron is playing with a full deck :), he is
correct. The numbers don't add up to 100.
I posted this recipe because in use it has been a great glaze and works
well in combination with other glazes I use. It was originally Tim
Derose's recipe.
Since I am a complete novice (am I the only one who detests the word
'newbie'?) at glaze calculation, I will take Ron's word that the recipe
is lacking in a few areas.
I would appreciate a definition on the word "durability" though. I
should add that I never fire this glaze to cone 6; it is always fired to
cone 8. At cone 6, it is more satiny and soft. It would show marks
from silverware. However, at cone 8, this has never happened. It has
been used for years and years with no crazing and no marks evident. I
don't understand the chemistry behind that, do not pretend to be a
chemist, but I do know from practical use that it seems quite durable.
Is there an explanation for this? It is fired with Tucker's mid smooth
stone which is pushed to cone 8 as well. This too, has never been a
problem.
I like knowing the rules, and then breaking them all........
Alison Hamilton
Dorset, ON
CLAYART@LSV.UKY.EDU wrote:
>
> ----------------------------Original message----------------------------
> This glaze is under supplied with silica and over supplied with MgO when I
> compare it with the limits I use to assess durability - I do not think it
> poses any great risk - unless any toxics are added to it.
>
> I am again wondering if I am playing with a full deck - the total is 50.40.
> I have used 1 bentonite, EPK as the kaolin, gerstley borate not colemanite.
> I also made zircopax a phantom material so that the SiO2 in it would not be
> included as available to the glass.
>
> In order for it to have enough SiO2 to match up with the limits I use you
> would have to add 8.0 silica - new total would be 57.40 - it would not be
> the same looking glaze - just trying to give some idea of just how short it
> is of SiO2.
>
> Anybody else come to the same conclusion?
>
> >----------------------------Original message----------------------------
> >I find this glaze to be really easy to work with (it's forgiving, thus
> >great for a school studio environment) and it's a nice satiny matt
> >white, depending on how high you fire it.
> >
> >Tim's White (cone 6-8, oxidation)
> >
> >Custer feldspar 15.75
> >Colemanite 4.5
> >Dolemanite 6.75
> >Talc 4.5
> >Whiting 2.25
> >Kaolin 6.75
> >Flint 4.5
> >Zircopax 3.4
> >plus 2% bentonite
>
> Ron Roy
> 93 Pegasus Trail
> Scarborough, Ontario
> Canada M1G 3N8
> Tel: 416-439-2621
> Fax: 416-438-7849
>
> Web page: http://digitalfire.com/education/people/ronroy.htm
Andrew Buck on mon 19 oct 98
Alison and All,
Glaze calculation is a good tool that, if you are having a problem, give a
good indication of what the problem may be and how one might go about
fixing it. Glaze calculations, however good they are, do not take
everything into account though. The person interpreting the results is
still a big factor in the usefulness of the outcome. If there is a
problem with a glaze, listen well to what can be learned through the tool
of glaze calculation. If there is no problem, don't get too excited about
the numbers not adding up. There might be a problem in the input data
like a change in the firing temperature or the interaction of the glaze
and the clay body or even something left out of the calculation process.
We are learning more about the chemistry of glazes all the time and our
ideas on durability and what is "safe" in a glaze are changing all the
time. In that sense we are all "newbies". (And that is the reason I,
also, do not like the term "newbie")
Listen to what all the "experts" tell you, then do what works.
On Sun, 18 Oct 1998, Alison Hamilton wrote:
> ----------------------------Original message----------------------------
> Drats!
>
> Wouldn't you know the first time I post a glaze recipe I'm caught like
> the proverbial deer in the headlights! And while I wouldn't want to be
> the one to comment on whether Ron is playing with a full deck :), he is
> correct. The numbers don't add up to 100.
>
> I posted this recipe because in use it has been a great glaze and works
>
> Since I am a complete novice (am I the only one who detests the word
> 'newbie'?) at glaze calculation, I will take Ron's word that the recipe
> is lacking in a few areas.
>
> I like knowing the rules, and then breaking them all........
>
> Alison Hamilton
> Dorset, ON
Andy Buck
Raincreek Pottery
Port Orchard, Washington
If all else fails, read the instructions!
Ron Roy on tue 20 oct 98
Dear Alison,
It is not my intention to embarass anyone and I don't like that part of
what I do when I post my opinion of a glaze. I believe most of us are using
glazes which are less than durable. I do feel it is important - expecially
for those trying to make a living making functional ware - that they at
least have some idea about what to expect when this aspect of potting is
not taken into consideration. I do appologize for embarassing you and give
you full credit for coming right back.
Glaze durability: Every glaze has certain charateristics - durability is
the charateristic which says something about the glazes ability to resist
chemical attack. If the glaze is durable then chemical attack from acid and
alkalies is minimized. This means - for instance - in a glaze short of
silica - acidic foods can break down the structure of the glass and the
glaze will dull with use - and release some of the components of that glaze
into food it comes in contact with. If a glaze has enough silica this
degrading of the glaze from acid attack will happen very little.
This is true as well with glazes which are short of alumina but in this
case the glaze will be degraded by alkalies. You may have noticed this
happening with your drinking glasses - after a time - especially if you
have a dishwasher - the glass will be come less than transparent. This is
alkalie actually etching the glass. You have to understand of course -
glass is short of alumina compared to most glazes. I would expect very
little - only that which comes along with the silica used to make it.
Back to your glaze fired at cone 8. In this case the glaze is even more
short of silica. and perhaps a little short of alumina as well. The MgO is
however just a small bit over.
In way of attoaning for this further bad news let me offer to try and fix
this glaze so that it is durable - If you are willing to mix and fire the
revisions and tell us how they worked you have a deal. Just contact me at
ronroy@total.net and I will send you some new glazes.- better tell me what
kind of clay you are useing so I can take that into account.
RR
>----------------------------Original message----------------------------
>Drats!
>
>Wouldn't you know the first time I post a glaze recipe I'm caught like
>the proverbial deer in the headlights! And while I wouldn't want to be
>the one to comment on whether Ron is playing with a full deck :), he is
>correct. The numbers don't add up to 100.
>
>I posted this recipe because in use it has been a great glaze and works
>well in combination with other glazes I use. It was originally Tim
>Derose's recipe.
>
>Since I am a complete novice (am I the only one who detests the word
>'newbie'?) at glaze calculation, I will take Ron's word that the recipe
>is lacking in a few areas.
>
>I would appreciate a definition on the word "durability" though. I
>should add that I never fire this glaze to cone 6; it is always fired to
>cone 8. At cone 6, it is more satiny and soft. It would show marks
>from silverware. However, at cone 8, this has never happened. It has
>been used for years and years with no crazing and no marks evident. I
>don't understand the chemistry behind that, do not pretend to be a
>chemist, but I do know from practical use that it seems quite durable.
>Is there an explanation for this? It is fired with Tucker's mid smooth
>stone which is pushed to cone 8 as well. This too, has never been a
>problem.
>
>I like knowing the rules, and then breaking them all........
>
>Alison Hamilton
>Dorset, ON
>
>> >Custer feldspar 15.75
>> >Colemanite 4.5
>> >Dolemanite 6.75
>> >Talc 4.5
>> >Whiting 2.25
>> >Kaolin 6.75
>> >Flint 4.5
>> >Zircopax 3.4
>> >plus 2% bentonite
Ron Roy
93 Pegasus Trail
Scarborough, Ontario
Canada M1G 3N8
Tel: 416-439-2621
Fax: 416-438-7849
Web page: http://digitalfire.com/education/people/ronroy.htm
Alison Hamilton on wed 21 oct 98
Ron,
I truly was not embarrassed - it was kind of humourous, actually.
However, I do appreciate your sensitivity and although you have
absolutely no need to atone, I am unfortunately selfish enough to take
you up on your very generous offer, especially since it was made in
front of witnesses!
I use Tucker's mid-smooth stone fired to cone 8 and although I have also
replied to you off-list, I wanted to let everyone know that I have
agreed to your bargain, cub scout honour. (ok, I wasn't a cub scout, or
a girl guide, but I bet the cub scouts had more fun.....)
Thanks again,
Alison Hamilton
Dorset, ON
CLAYART@LSV.UKY.EDU wrote:
>
> ----------------------------Original message----------------------------
> Dear Alison,
>
> It is not my intention to embarass anyone and I don't like that part of
> what I do when I post my opinion of a glaze. I believe most of us are using
> glazes which are less than durable. I do feel it is important - expecially
> for those trying to make a living making functional ware - that they at
> least have some idea about what to expect when this aspect of potting is
> not taken into consideration. I do appologize for embarassing you and give
> you full credit for coming right back.
>
> Glaze durability: Every glaze has certain charateristics - durability is
> the charateristic which says something about the glazes ability to resist
> chemical attack. If the glaze is durable then chemical attack from acid and
> alkalies is minimized. This means - for instance - in a glaze short of
> silica - acidic foods can break down the structure of the glass and the
> glaze will dull with use - and release some of the components of that glaze
> into food it comes in contact with. If a glaze has enough silica this
> degrading of the glaze from acid attack will happen very little.
>
> This is true as well with glazes which are short of alumina but in this
> case the glaze will be degraded by alkalies. You may have noticed this
> happening with your drinking glasses - after a time - especially if you
> have a dishwasher - the glass will be come less than transparent. This is
> alkalie actually etching the glass. You have to understand of course -
> glass is short of alumina compared to most glazes. I would expect very
> little - only that which comes along with the silica used to make it.
>
> Back to your glaze fired at cone 8. In this case the glaze is even more
> short of silica. and perhaps a little short of alumina as well. The MgO is
> however just a small bit over.
>
> In way of attoaning for this further bad news let me offer to try and fix
> this glaze so that it is durable - If you are willing to mix and fire the
> revisions and tell us how they worked you have a deal. Just contact me at
> ronroy@total.net and I will send you some new glazes.- better tell me what
> kind of clay you are useing so I can take that into account.
>
> RR
>
Alison Hamilton on tue 10 nov 98
Finally! the results are in.......
I am back with the results of my tests regarding Ron's revisions of the
glaze recipe I posted in response to this request.
This was the original recipe called Tim's White, fired to Cone 8 ox:
Custer feldspar 15.75
Colemanite 4.5
Dolemanite 6.75
Talc 4.5
Whiting 2.25
Kaolin 6.75
Flint 4.5
Zircopax 3.4
plus 2% bentonite
As Ron pointed out, it was, er, lacking in a few areas........
I tested the original recipe for durability, using one tile as a control
while another one sat in cider vinegar for 2.5 days (longer than
required, but who knows how long someone might leave something acetic
sitting around in a bowl?). I examined the tiles with a magnifying
glass, but unfortunately I was unable to see much of a difference
between the two of them. However, I rubbed the blunt end of a metal pin
tool on the tile exposed to the acid and the marks it left did not
easily rub off and in fact, looked like they left a more permanent mark.
Ron kindly sent me 3 revisions of the recipe, one of which was a
combination of the other 2. All three recipes were mixed. However, I
was not able to use all of the ingredients Ron specified. I had to
substitue colemanite for the gerstley borate since it was all I had
available. Although someone on clayart posted the chemical analysis of
these two ingredients awhile ago and made it quite clear that they are
different, suppliers seem to think they are the same and will often send
colemanite instead of gerstley borate.
I also had to use superpax instead of zircopax. I'm hoping that these
substitutions do not change the durability/functionality of the glaze.
All three tests were fired to cone 8, oxidation.
Revision #1
Custer spar 42.00
Gers. borate, 9/97 6.00 (substituted colemanite)
Dolomite 11.00
Talc 8.00
Whiting 4.00
EPK 16.00
Silica 13.00
Zircopax 7.50 (substituted superpax)
Bentonite 2.00
one glass of white wine (in the tester, not the glaze!)
Total 109.50
Revision #3
Custer spar 34.00
Gers. borate, 9/97 3.00 (substituted colemanite)
Dolomite 12.00
Talc 3.00
Whiting 8.00
EPK 19.00
Silica 21.00
Zircopax 7.00 (substituted superpax)
Bentonite 2.00
Total 109.00
Revision #2 (revision #1 plus revision #3)
Custer spar 38.00
Gers. borate, 9/97 4.50 (substituted colemanite)
Dolomite 11.50
Talc 5.50
Whiting 6.00
EPK 17.50
Silica 17.00
Zircopax 7.25 (substituted superpax)
Bentonite 2.00
Total 109.25
All three glazes had a good finish, smoothed out well during the firing
and were VERY nice! The double dipped part of the tile was significantly
whiter than the original recipe. This is only an issue inasmuch as it
would affect the dilution of any slips or underglazes used underneath
the glaze. In fact, one tile was tested with revision #3 over albany
slip and while the slip was a little runnier than usual, it was only
slightly more muted under the glaze than it have been with the original
recipe.
Revision #1 was the shiniest of the three, with a very slight break to
it. Revision #3 was the most satiny and provided the most contrast to
other glossy glazes that were also tested on the same tile.
All three revisions were also rubbed with the blunt end of a pin tool.
These marks rubbed off and upon examination with the magnifying glass,
did not appear to leave any permanent scratches.
Ron's comment on sending me these recipes was that #3 was the most
durable of the 3, with #2 being a close second. He felt that #1 was
still a little over with the MgO, but not significantly.
Ron, after having been through this process, I now feel I can say that
you are DEFINITELY playing with a full deck!!
It has certainly helped me to become much more aware of the importance
of glaze calculation and that simply obtaining recipes from other
potters is no guarantee of their safety, no matter how well they appear
to work.
Thanks so much for the education and assistance!
Clayarters, all three revisions are nice white glazes if you're looking
for one!
Alison Hamilton
Dorset, ON
----------------------------Original message----------------------------
> Dear Alison,
>
> It is not my intention to embarass anyone and I don't like that part of
> what I do when I post my opinion of a glaze. I believe most of us are using
> glazes which are less than durable. I do feel it is important - expecially
> for those trying to make a living making functional ware - that they at
> least have some idea about what to expect when this aspect of potting is
> not taken into consideration. I do appologize for embarassing you and give
> you full credit for coming right back.
>
> Glaze durability: Every glaze has certain charateristics - durability is
> the charateristic which says something about the glazes ability to resist
> chemical attack. If the glaze is durable then chemical attack from acid and
> alkalies is minimized. This means - for instance - in a glaze short of
> silica - acidic foods can break down the structure of the glass and the
> glaze will dull with use - and release some of the components of that glaze
> into food it comes in contact with. If a glaze has enough silica this
> degrading of the glaze from acid attack will happen very little.
>
> This is true as well with glazes which are short of alumina but in this
> case the glaze will be degraded by alkalies. You may have noticed this
> happening with your drinking glasses - after a time - especially if you
> have a dishwasher - the glass will be come less than transparent. This is
> alkalie actually etching the glass. You have to understand of course -
> glass is short of alumina compared to most glazes. I would expect very
> little - only that which comes along with the silica used to make it.
>
> Back to your glaze fired at cone 8. In this case the glaze is even more
> short of silica. and perhaps a little short of alumina as well. The MgO is
> however just a small bit over.
>
> In way of attoaning for this further bad news let me offer to try and fix
> this glaze so that it is durable - If you are willing to mix and fire the
> revisions and tell us how they worked you have a deal. Just contact me at
> ronroy@total.net and I will send you some new glazes.- better tell me what
> kind of clay you are useing so I can take that into account.
>
> RR
>
Marley Wolhud on tue 10 nov 98
Alison, curious as to why you substituted zircopax with superpax. I am
still trying to figure out the various components of ultrox, zirco and
superpax. I guess ultrox and zirco are basically the same, but what is
superpax? Actually I do have some since my supplier sent me some in
error.
Diane Chen
Edouard Bastarache on wed 11 nov 98
Hello Marley,
It appears to me that Ultrox is more refractory than Zircopax.
You could prove this with a couple of simple line-blends
between Ultrox and a flux as well as Zircopax and a flux.
Five percent increments ought to show you which melt first;
but, often one can be substituted for by the other one.
Later,
Edouard Bastarache
edouardb@sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/~edouardb/
----------
> De : Marley Wolhud
> A : CLAYART@LSV.UKY.EDU
> Objet : Re: alpine white-glaze please
> Date : 10 novembre, 1998 12:12
>
> ----------------------------Original message----------------------------
> Alison, curious as to why you substituted zircopax with superpax. I am
> still trying to figure out the various components of ultrox, zirco and
> superpax. I guess ultrox and zirco are basically the same, but what is
> superpax? Actually I do have some since my supplier sent me some in
> error.
>
> Diane Chen
Alison Hamilton on wed 11 nov 98
Diane,
er, umm, because it's what I had sitting on the shelf?
I'm NOT the one to be answering this question! Could somebody else
please help Diane out with this?
Alison Hamilton
Dorset, ON
Marley Wolhud wrote:
>
> ----------------------------Original message----------------------------
> Alison, curious as to why you substituted zircopax with superpax. I am
> still trying to figure out the various components of ultrox, zirco and
> superpax. I guess ultrox and zirco are basically the same, but what is
> superpax? Actually I do have some since my supplier sent me some in
> error.
>
> Diane Chen
Caryl W. on wed 11 nov 98
>Date: Tue, 10 Nov 1998 12:12:20 EST
>Reply-To: Ceramic Arts Discussion List
>From: Marley Wolhud
>Subject: Re: alpine white-glaze please
>To: CLAYART@LSV.UKY.EDU
>
>----------------------------Original
message----------------------------
>Alison, curious as to why you substituted zircopax with superpax. I am
>still trying to figure out the various components of ultrox, zirco and
>superpax. I guess ultrox and zirco are basically the same, but what is
>superpax? Actually I do have some since my supplier sent me some in
>error.
>
>Diane Chen
I've always used Superpax as the opacifier for my white glaze but I
really don't know what the difference is between the procucts?I'd be
interested in that as well.I add between 10-15% for a really nice,true
white to my base glaze.
Caryl
______________________________________________________
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