Wanda Holmes on sat 26 apr 03
I am trying to determine whether I can limit my bulk glaze materials to
a set of 5 or so items and I have a question about your choice of
feldspar, CaO source, frit, and clay in your recipes. Is the choice of
feldspar (G-200, Custer, or Nepheline Syenite) based simply on the
recipe to formula conversion problem or are there specific
characteristics of each raw material - beyond the oxides they source -
that led you to choose one over the other for a specific glaze? The
same question applies to the other items as well -
Wollastonite vs. whiting as a source of CaO?
Epk vs. Kentucky OM#4?
Frit 3134 vs. 3124 vs. 3195?
The strategy that I'm considering is to keep nepheline syenite,
wollastonite, epk, C&C ball clay (I use it in my body), and Frit 3134 on
hand in bulk and to substitute as appropriate in recipes calling for
alternate materials; adding to my stock only when a desirable glaze
cannot be successfully modified.
I suppose the basic question I'm asking is, in the opinion of clayarters
everywhere, is this a reasonable strategy or one that I'm likely to find
extremely limiting?
There are 3 considerations behind all this: 1) buying materials at the
most favorable rate, 2) the space I have available to store these bulk
materials, and 3) whether tis better to choose a glaze family and get to
know it in all its nuances or to continue to experiment widely - another
philosophical point on which I would love to hear others' opinions.
Wanda
Austin, Tx ... at the start of what promises to be a beautiful spring
day
Russel Fouts on sun 27 apr 03
Wanda
Well, I'm not Ron nor John (and I don't play either of them on TV)
>> There are 3 considerations behind all this: 1) buying materials at the most favorable rate, 2) the space I have available to store these bulk materials, and 3) whether tis better to choose a glaze family and get to know it in all its nuances or to continue to experiment widely - another philosophical point on which I would love to hear others' opinions. <<
I definitely have an opiniion on #3. YES! Find one or two things(glazes,
clays, methods of making, methods of firing) and get to know them
thoroughly. Use the "constraints" or limits of that "thing" to as a
basis of further creativity.
In my smoke fired work, I use one clay, an orange sig (made from the one
clay body), a white sig and my electric kiln. I've been working this way
for 7 years now. I know my materials and methods really well but they
still manage to surprise me.
The limits force me to "inside" for creative ideas. I find it a very
exciting way to work.
Now, I've decided that I'd like to try maiolica. Same body, new white
maiolica glaze (Ostermann), same kiln. One of the reasons for getting
into this was to start working with colors other than black, orange,
brown and white (smoke fire colors). But I've fallen so in love with
this white glaze, the brilliance, texture, the way it breaks over
texture, etc that it may be a long time before I start experimenting
with the colors.
Have a look in my gallery and at the top of the Clayart Show Window on
my site at http://www.mypots.com.
Choose your materials well and get to know them through and through.
Russel
--
Russel Fouts
Mes Potes & Mes Pots
Brussels, Belgium
Tel: +32 2 223 02 75
Mobile: +32 476 55 38 75
Http://www.mypots.com
Home of "The Potters Portal"
Over 1800 Pottery Links!
Updated frequently
"To announce that there must be no criticism of the president,
or that we are to stand by the president, right or wrong,
is not only unpatriotic and servile, but is morally treasonable
to the American public."
U.S. President (and Nobel Peace Prize winner) Theodore Roosevelt.
Tony Hansen on sun 27 apr 03
I would be nice if the only consideration was chemistry,
that we could view materials as simple sources of oxides.
But materials are also employed for mineralogical and
physical properties reasons and for combinations of
mineral, chemistry and physics reasons.
We are working on capturing these three levels of information
at www.ceramicmaterials.info
There are thousands of pages there and feedback forms on
every page.
This is a work in progress right now with many albeit
optimistic goals. But I have been doing online material
information for 12 years now so am starting to figure it out.
The generic wollastonite record is a good example of the
fact that chemistry is not the only issue.
http://digitalfire.ab.ca/cermat/ceramicmaterials/material.php?id=1705
Still, the idea of a base-recipe-with-adjustments approach
is one toward which I certainly am pressing, I have not
reaching it but certainly use many less materials than
in the past.
> I am trying to determine whether I can limit my bulk glaze materials to
> a set of 5 or so items and I have a question about your choice of
> feldspar, CaO source, frit, and clay in your recipes. Is the choice of
> feldspar (G-200, Custer, or Nepheline Syenite) based simply on the
> recipe to formula conversion problem or are there specific
> characteristics of each raw material - beyond the oxides they source -
> that led you to choose one over the other for a specific glaze? The
> same question applies to the other items as well -
> Wollastonite vs. whiting as a source of CaO?
========
Tony Hansen
John Hesselberth on sun 27 apr 03
Hi Wanda,
I would encourage you to limit your materials and your glazes to as few
as possible. One or two base glazes and a small handful of color
variants is more than enough for most potters. I think most of us go
through an exploratory stage when we want to try everything in sight
and then a focusing stage where we pick the best and learn to use them
really well. You sound like you are ready to focus.
With respect to specific materials you can certainly eliminate either
Custer or G-200 -- they are very similar; however neph sy can be very
useful if you still plan to experiment. Either whiting or wollastonite
can be your primary source of calcium. I lean toward wollastonite; I
think Ron leans toward whiting. I prefer wollastonite for the smaller
amount of gas generation and the possibility that it results in better
melting at cone 6. I put up with its nasty dispersing characteristics
during initial mix of a batch. With respect to frits you can probably
stop stocking 3195 and 3124 in favor of 3134. 3134 has no alumina and,
therefore, allows you to put more clay in the recipe--almost always a
good thing to do.
I would keep ball clay over EPK if you want to get down to one clay. It
helps you retain some of the 'magic' of gerstley borate when developing
frit-based replacements.
The disadvantage of doing all this is that you might not be able to
make some specific compositions you want to test. I would not have been
able to get some of the glazes in Mastering Cone 6 Glazes without a
more complete set of materials. So if you do it, do it with the
recognition that it is time to focus on a couple of good bases and only
do occasional excursions away from those--not a bad thing to do at all.
In fact on my own pots (as opposed to any future book considerations)
that is what I am trying to do.
Regards,
John
On Saturday, April 26, 2003, at 11:04 AM, Wanda Holmes wrote:
> I am trying to determine whether I can limit my bulk glaze materials to
> a set of 5 or so items and I have a question about your choice of
> feldspar, CaO source, frit, and clay in your recipes. Is the choice of
> feldspar (G-200, Custer, or Nepheline Syenite) based simply on the
> recipe to formula conversion problem or are there specific
> characteristics of each raw material - beyond the oxides they source -
> that led you to choose one over the other for a specific glaze? The
> same question applies to the other items as well -
>
> Wollastonite vs. whiting as a source of CaO?
>
> Epk vs. Kentucky OM#4?
>
> Frit 3134 vs. 3124 vs. 3195?
>
> The strategy that I'm considering is to keep nepheline syenite,
> wollastonite, epk, C&C ball clay (I use it in my body), and Frit 3134
> on
> hand in bulk and to substitute as appropriate in recipes calling for
> alternate materials; adding to my stock only when a desirable glaze
> cannot be successfully modified.
>
> I suppose the basic question I'm asking is, in the opinion of
> clayarters
> everywhere, is this a reasonable strategy or one that I'm likely to
> find
> extremely limiting?
>
> There are 3 considerations behind all this: 1) buying materials at the
> most favorable rate, 2) the space I have available to store these bulk
> materials, and 3) whether tis better to choose a glaze family and get
> to
> know it in all its nuances or to continue to experiment widely -
> another
> philosophical point on which I would love to hear others' opinions.
>
> Wanda
> Austin, Tx ... at the start of what promises to be a beautiful spring
> day
>
> _______________________________________________________________________
> _______
> 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.
>
>
http://www.frogpondpottery.com
http://www.masteringglazes.com
Bryan on sun 27 apr 03
----- Original Message -----
From: "John Hesselberth"
[snip]
> I prefer wollastonite for the smaller
> amount of gas generation and the possibility that it results in better
> melting at cone 6. I put up with its nasty dispersing characteristics
> during initial mix of a batch.
I have been setting aside wollastonite when I weigh out a batch of glaze
materials. Filling a blender about half full of water and them adding
wollastnite. A couple minutes gets rid of all the lumps, and it just
pours through the screen.
>
> The disadvantage of doing all this is that you might not be able to
> make some specific compositions you want to test. I would not have
been
> able to get some of the glazes in Mastering Cone 6 Glazes without a
> more complete set of materials. So if you do it, do it with the
> recognition that it is time to focus on a couple of good bases and
only
> do occasional excursions away from those--not a bad thing to do at
all.
> In fact on my own pots (as opposed to any future book considerations)
> that is what I am trying to do.
>
> Regards,
That book sure provides plenty of starting points or base glazes to play
with. After twenty years of neriage and nerikome I have started using
something other than clear glaze.
Bryan
Paul Lewing on sun 27 apr 03
on 4/27/03 12:18 PM, John Hesselberth at john@FROGPONDPOTTERY.COM wrote:
> 3) whether tis better to choose a glaze family and get
>> to
>> know it in all its nuances or to continue to experiment widely -
>> another
>> philosophical point on which I would love to hear others' opinions.
>>
I'm one of those that come down on the other side of this question from most
people you've heard from. I probably have a little of virtually every glaze
chemical that any supplier sells. I don't have all the frits, of course
(there are hundreds) but I probably have some of at least 20. I test an
amazing number of glaze recipes from outside sources, and I am continually
making up and modifying new glaze recipes. If you were to list all the
glazes in a firing of mine, that list would not be the same for more than
one or two firings in a row. My glazing table will always have at least 20
different containers on it, and on a large tile mural, it's not unusual for
me to use 35 different glazes.
I'm not saying anyone else should do it this way, but that's how I've always
done it, for several reasons. For one thing, my first and foremost hero,
Dave Shaner did it that way. And I'm just endlessly fascinated by the whole
thing. And I was once told that the secret to an individual style was to
find something that no one but you was WILLING to do, because you'd never
find anything that no one HAD ever done before. It may not be a smart way
or an efficient way, or a cost-effective way, but it's MY way, and I like
it, and it's served me well.
Paul Lewing, Seattle
David Beumee on mon 28 apr 03
Whoever gave you that piece of advice on developing a personal style
was a genius. I hope others will listen carefully.
David Beumee
4/27/03 6:27:56 PM, Paul Lewing wrote:
>on 4/27/03 12:18 PM, John Hesselberth at john@FROGPONDPOTTERY.COM wrote:
>
>> 3) whether tis better to choose a glaze family and get
>>> to
>>> know it in all its nuances or to continue to experiment widely -
>>> another
>>> philosophical point on which I would love to hear others' opinions.
>>>
>
>I'm one of those that come down on the other side of this question from most
>people you've heard from. I probably have a little of virtually every glaze
>chemical that any supplier sells. I don't have all the frits, of course
>(there are hundreds) but I probably have some of at least 20. I test an
>amazing number of glaze recipes from outside sources, and I am continually
>making up and modifying new glaze recipes. If you were to list all the
>glazes in a firing of mine, that list would not be the same for more than
>one or two firings in a row. My glazing table will always have at least 20
>different containers on it, and on a large tile mural, it's not unusual for
>me to use 35 different glazes.
>I'm not saying anyone else should do it this way, but that's how I've always
>done it, for several reasons. For one thing, my first and foremost hero,
>Dave Shaner did it that way. And I'm just endlessly fascinated by the whole
>thing. And I was once told that the secret to an individual style was to
>find something that no one but you was WILLING to do, because you'd never
>find anything that no one HAD ever done before. It may not be a smart way
>or an efficient way, or a cost-effective way, but it's MY way, and I like
>it, and it's served me well.
>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.
>
Ron Roy on thu 1 may 03
Hi Wanda,
Interesting question.
There are good reasons for having a variety of materials. The trouble most
of us have is because we all started with recipes we got from all over the
place and consequently must have a wide assortment of materials.
This is unnecessary now if you know how to us a glaze calculator - one
could have a much shorter list of materials and simply sub them in to most
of those gleaned recipes.
You will probably need about 3 frits - this gets a bit complicated but for
these reasons. Sometimes you don't need a lot of calcium for instance -
when making a high MgO glaze. Some times you need some alumina in the frit
to off set high raw clay content like in alumina mattes.
You need two kinds of clay - EPK and a ball clay.
One spar will do the job - pick one with high about 12% KNaO like G200. If
you are working at cone 6 you will find Neph Sy handy but it is a
problematic material and you should limit it's use whenever you can.
I have no preference for whiting over wollastonite - sometimes you need the
whiting because you don't want the extra silica in the wolastonite.
Talc is an excellent source of MgO but again dolomite is handy when you
don't need all that extra silica.
If you are working with a glaze calculator you will eventually see which
materials you will need as you progress. What you need to do is try to fit
all the glazes you try into the materials you have - if they won't fit you
need to look for a material that will.
A word of caution - beware of glazes that have few raw materials in them -
and if they do make sure the materials are relatively stable - Gerstley
Borate would not be one and ball clays tend to vary more than you would
imagine.
I also think that working with one or two base glazes is a good plan but
most potters want more variety than that. Again - if you can use a
calculator and understand how controlled cooling works - you can get quite
a variety of colours and surfaces out of surprisingly few base glazes -
especially if you start layering them. So much more productive than trying
endless recipes trying to find the ones that suit you.
If you have further questions about this I will try to answer them - I find
it interesting - limit the number of materials and get a wide variety of
colours and surfaces.
RR
>I am trying to determine whether I can limit my bulk glaze materials to
>a set of 5 or so items and I have a question about your choice of
>feldspar, CaO source, frit, and clay in your recipes. Is the choice of
>feldspar (G-200, Custer, or Nepheline Syenite) based simply on the
>recipe to formula conversion problem or are there specific
>characteristics of each raw material - beyond the oxides they source -
>that led you to choose one over the other for a specific glaze? The
>same question applies to the other items as well -
>
>Wollastonite vs. whiting as a source of CaO?
>
>Epk vs. Kentucky OM#4?
>
>Frit 3134 vs. 3124 vs. 3195?
>
>The strategy that I'm considering is to keep nepheline syenite,
>wollastonite, epk, C&C ball clay (I use it in my body), and Frit 3134 on
>hand in bulk and to substitute as appropriate in recipes calling for
>alternate materials; adding to my stock only when a desirable glaze
>cannot be successfully modified.
>
>I suppose the basic question I'm asking is, in the opinion of clayarters
>everywhere, is this a reasonable strategy or one that I'm likely to find
>extremely limiting?
>
>There are 3 considerations behind all this: 1) buying materials at the
>most favorable rate, 2) the space I have available to store these bulk
>materials, and 3) whether tis better to choose a glaze family and get to
>know it in all its nuances or to continue to experiment widely - another
>philosophical point on which I would love to hear others' opinions.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Russel Fouts on fri 2 may 03
Ron,
>>I find it interesting - limit the number of materials and get a wide variety of colours and surfaces. <<
I agree competely. Use a few materials and develop lots of different
techniques to apply/use them. Really pushes your creativity.
About those frits, which 3 would you recommend. 3110 seems to be used by
everyone.
Russel
--
Russel Fouts
Mes Potes & Mes Pots
Brussels, Belgium
Tel: +32 2 223 02 75
Mobile: +32 476 55 38 75
Http://www.mypots.com
Home of "The Potters Portal"
Over 1800 Pottery Links!
Updated frequently
"To announce that there must be no criticism of the president, or that
we are to stand by the president, right or wrong, is not only
unpatriotic and servile, but is morally treasonable to the American
public." --U.S. President (and Nobel Peace Prize winner) Theodore
Roosevelt.
Barry Salaberry on fri 2 may 03
"You will probably need about 3 frits - this gets a bit complicated but =
for
these reasons."
Ron,=20
would you please suggest three specific frits to start with?
Barry
Ned Ludd on sat 3 may 03
Hi Ron
So, using a glaze calculator we can simply sub in materials to get
the _same_ glaze?
I wish!
I tested a c10R celadon that included whiting, about twenty percent.
Using HyperGlaze I recalced the recipe - precisely - to use
wollastonite instead. Result was close, but no cigar. The difference?
The Wolla version had a greyish hue. It lacked the clarity and zing
of the Whiting version.
My hunch is that whiting comes 'cleaner' than wolla. Therefore I have
more confidence in whiting - in celadons, anyway - and I avoid using
wolla in glazes where color tint is critical.
Dependence on theory is not infallible: the map is not the country.
best
Ned
Ron Roy wrote:
>Hi Wanda,
>
>Interesting question.
>
>There are good reasons for having a variety of materials. The trouble most
>of us have is because we all started with recipes we got from all over the
>place and consequently must have a wide assortment of materials.
>
>This is unnecessary now if you know how to us a glaze calculator - one
>could have a much shorter list of materials and simply sub them in to most
>of those gleaned recipes.
>I have no preference for whiting over wollastonite - sometimes you need the
>whiting because you don't want the extra silica in the wolastonite.
>
>
>I also think that working with one or two base glazes is a good plan but
>most potters want more variety than that. Again - if you can use a
>calculator and understand how controlled cooling works - you can get quite
>a variety of colours and surfaces out of surprisingly few base glazes -
>especially if you start layering them. So much more productive than trying
>endless recipes trying to find the ones that suit you.
>
>If you have further questions about this I will try to answer them - I find
>it interesting - limit the number of materials and get a wide variety of
>colours and surfaces.
>
>RR
>
>
>
>>I am trying to determine whether I can limit my bulk glaze materials to
>>a set of 5 or so items and I have a question about your choice of
> >feldspar, CaO source, frit, and clay in your recipes.
Brenda Anderson on sun 4 may 03
I am just beginning to mix my own glazes. Actually I have only bought the
materials. What is a glaze calculator and where do I get one? Am I ready
for that yet or should I stick with the old faithfuls first?
With cone 10 glazes must I spray, brush or dip. If brushing must the glaze
be smooth and even as in low fire?
With the toxic glazes do you mean respiratory or contact or both?
Lots of questions---------
Daughter of Clay
Brenda
----- Original Message -----
From: "Ned Ludd"
To:
Sent: Saturday, May 03, 2003 10:06 AM
Subject: Re: Glaze materials question for Ron & John
> Hi Ron
>
> So, using a glaze calculator we can simply sub in materials to get
> the _same_ glaze?
>
> I wish!
>
> I tested a c10R celadon that included whiting, about twenty percent.
> Using HyperGlaze I recalced the recipe - precisely - to use
> wollastonite instead. Result was close, but no cigar. The difference?
> The Wolla version had a greyish hue. It lacked the clarity and zing
> of the Whiting version.
>
> My hunch is that whiting comes 'cleaner' than wolla. Therefore I have
> more confidence in whiting - in celadons, anyway - and I avoid using
> wolla in glazes where color tint is critical.
>
> Dependence on theory is not infallible: the map is not the country.
>
> best
>
> Ned
>
> Ron Roy wrote:
> >Hi Wanda,
> >
> >Interesting question.
> >
> >There are good reasons for having a variety of materials. The trouble
most
> >of us have is because we all started with recipes we got from all over
the
> >place and consequently must have a wide assortment of materials.
> >
> >This is unnecessary now if you know how to us a glaze calculator - one
> >could have a much shorter list of materials and simply sub them in to
most
> >of those gleaned recipes.
>
>
> >I have no preference for whiting over wollastonite - sometimes you need
the
> >whiting because you don't want the extra silica in the wolastonite.
> >
> >
> >I also think that working with one or two base glazes is a good plan but
> >most potters want more variety than that. Again - if you can use a
> >calculator and understand how controlled cooling works - you can get
quite
> >a variety of colours and surfaces out of surprisingly few base glazes -
> >especially if you start layering them. So much more productive than
trying
> >endless recipes trying to find the ones that suit you.
> >
> >If you have further questions about this I will try to answer them - I
find
> >it interesting - limit the number of materials and get a wide variety of
> >colours and surfaces.
> >
> >RR
> >
> >
> >
> >>I am trying to determine whether I can limit my bulk glaze materials to
> >>a set of 5 or so items and I have a question about your choice of
> > >feldspar, CaO source, frit, and clay in your recipes.
>
>
>
____________________________________________________________________________
__
> 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.
Tony Hansen on sun 4 may 03
> So, using a glaze calculator we can simply sub in materials to get
> the _same_ glaze?
> I wish!
> I tested a c10R celadon that included whiting, about twenty percent.
> Using HyperGlaze I recalced the recipe - precisely - to use
> wollastonite instead. Result was close, but no cigar. The difference?
> The Wolla version had a greyish hue. It lacked the clarity and zing
> of the Whiting version.
> My hunch is that whiting comes \'cleaner\' than wolla. Therefore I have
> more confidence in whiting - in celadons, anyway - and I avoid using
> wolla in glazes where color tint is critical.
> Dependence on theory is not infallible: the map is not the country.
It is not infallible but it is better than working only
on the material level. If you also consider the mineral
and physical differences of wolly there is no
doubt in my mind that it could be made to work with by
also taking these things into account.
Is the greyish hue crystallization? Does the glaze
have the same melt fluidity? If it is more fluid using
wollastonite, that is a mineral issue, its SiO2 is more
easily dissolved in the glass than SiO2 from silica.
Perhaps not as much CaO is needed. Having a flow tester
is great for measuring fluidity.
Does the glaze have the same population of suspended
micro-bubbles?
========
clayart@digitalfire.com
Ron Roy on mon 5 may 03
Hi Ned,
I hope you don't discount the value of material substitution because it did
not work for one glaze.
There can be other reasons your experiment did not work. Having the correct
analysis for the wollastonite and the whiting you are using would be one
reason for the failure. It is important to keep your materials table
accurate for the materials you use. The is slightly better melting when you
use CaO and SiO2 combined - as with wollastonite - did you take that into
account? Best to do a short line blend in cased like this if you want exact
duplication.
It is my job to sub in body clays and materials in glazes for two
companies. Over the last 15 years I can only say - it works for the great
majority of clays and glazes.
I would be interested in trying to do the substitution for your glaze
although - in your case - it would only be an exercise to prove a point
because both wollastonite and whiting are still available. All I need is
the recipe and the analysis for the whiting and wollastonite you are using.
I have to add - in the same breath - to the practiced eye - the results are
seldom a perfect match - some times better though.
I speak from experience - not from theory.
RR
>So, using a glaze calculator we can simply sub in materials to get
>the _same_ glaze?
>
>I wish!
>
>I tested a c10R celadon that included whiting, about twenty percent.
>Using HyperGlaze I recalced the recipe - precisely - to use
>wollastonite instead. Result was close, but no cigar. The difference?
>The Wolla version had a greyish hue. It lacked the clarity and zing
>of the Whiting version.
>
>My hunch is that whiting comes 'cleaner' than wolla. Therefore I have
>more confidence in whiting - in celadons, anyway - and I avoid using
>wolla in glazes where color tint is critical.
>
>Dependence on theory is not infallible: the map is not the country.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
iandol on tue 6 may 03
Dear Brian Molanphy,
You ask about my use of the term "Auxiliary" with reference to Group 2 =
Elements. Since you quote my posting I think it is imperative that I =
answer you.
I have a maverick attitude to the idea that the Group 2 Elements which =
contrasts with popular views about the behaviour and functions of =
fluxing agents. I will not accept the insistent opinion that Group 2 =
Oxides assist or cause melting.
Melting is a function I attribute to substances which bring Group One =
Elements, Li, K, Na, to the party since they all have low melting =
points. Check the mp's of their carbonates
Materials which are compounded from Group 2 Elements, Ca, Ba, Sr =
contribute other qualities, but only after they have dissolved in the =
melt. Before dissolution, particularly those Oxides formed from the =
decomposition of Carbonates, are refractory in nature. I would add a =
caveat at this point. This does not apply to Frits or when the Group 2 =
Elements are compounded with Boron.
So to your suggestion of Neph Sy. That I would consider a melting flux =
whereas your other example, Wollastonite, which has a melting point of =
1544 deg Celsius would be an auxiliary. Only under special circumstances =
would that material contribute to fusion.
I hope that explains my original comments.
Best regards,
Ivor Lewis
Gail Dapogny on tue 6 may 03
Hi Ron and Ned,
Interesting thread. I am finishing up a glaze calculation course using
Insight with one of Ron's prodigies (Margaret Barlow), which has opened up
a new world for me. A friend of mine was using a celadon (cone 9-10, gas
red.) which was constantly pitting in the firing. I used my new found
knowledge (slim pickins compared to Ron) and subbed in wollastonite for the
whiting (which was 20%) along with some other changes to account for the
added silica. The new glaze came out looking like the old, and did not
have pinholes in the initial firing. If it continues successfully, I will
be really excited!!
Gail Dapogny in Ann Arbor
P.S. Ron, if you fool with Ned's glaze, I will be eager to see what you
come up with.
>Hi Ned,
>
>I hope you don't discount the value of material substitution because it did
>not work for one glaze.
>
>There can be other reasons your experiment did not work. Having the correct
>analysis for the wollastonite and the whiting you are using would be one
>reason for the failure. It is important to keep your materials table
>accurate for the materials you use. The is slightly better melting when you
>use CaO and SiO2 combined - as with wollastonite - did you take that into
>account? Best to do a short line blend in cased like this if you want exact
>duplication.
>
>It is my job to sub in body clays and materials in glazes for two
>companies. Over the last 15 years I can only say - it works for the great
>majority of clays and glazes.
>
>I would be interested in trying to do the substitution for your glaze
>although - in your case - it would only be an exercise to prove a point
>because both wollastonite and whiting are still available. All I need is
>the recipe and the analysis for the whiting and wollastonite you are using.
>
>I have to add - in the same breath - to the practiced eye - the results are
>seldom a perfect match - some times better though.
>
>I speak from experience - not from theory.
>
>RR
>
>
>
>>I tested a c10R celadon that included whiting, about twenty percent.
>>Using HyperGlaze I recalced the recipe - precisely - to use
>>wollastonite instead. Result was close, but no cigar. The difference?
>>The Wolla version had a greyish hue. It lacked the clarity and zing
>>of the Whiting version.
>>
>>My hunch is that whiting comes 'cleaner' than wolla. Therefore I have
>>more confidence in whiting - in celadons, anyway - and I avoid using
>>wolla in glazes where color tint is critical.
>>
>>Dependence on theory is not infallible: the map is not the country.
Ron Roy on sat 10 may 03
I thought I had posted this to Clay Art but it only went to Russel -
thought otherws would want to see it - RR
Hi Russel,
I guess this could be seen as a temperature sensitive question and I am
wondering - if I was working at 04 would I answer this question
differently. Perhaps the answer to that will come later - or maybe not at
all - depends how important my brain thinks it is.
Having the analysis of as many frits as possible is a great help in
deciding this - and knowing which are available. That way you can decide
which will be of the most use based on the kind of glazes you use.
The Frit I use the most is 3134 because it has no alumina - so I can get
enough clay in the glaze to provide good suspension. There are some
situations where it is not good enough. For instance - if a glaze has more
than 30% Gerstley Borate it will not provide enough B2O3 in many cases. You
would have to find another source of boron - perhaps from Cady Cal or a
Frit with more boron.
F3134 has a lot of CaO so if you have a glaze with high MgO you might not
be able to use it. In that case Frit 3278 with much less CaO (and again no
alumina) might be better. I does not have quite as much B2O3 however.
Then there is the situation where the glaze has a lot of alumina and it is
difficult to not have too much clay in the glaze - perhaps Frit 3195 would
be appropriate because it has a fair amount of alumina - a good amount of
B2O3 and a little MgO.
If you need to bump up the KNaO and keep the alkaline content up - as in my
example of replacing Neph Sy - then Frit 3110 is the ticket. It is also
very useful when doing those alkaline turquoise glazes.
I have many more Frits of course because I work on so many different glazes
- the best advice I can give is - find out which Frits you can get easily -
study your glazes and try to see which would be the most useful. If you
have questions I may be able to help you choose but I will need to see the
analysis.
RR
>About those frits, which 3 would you recommend. 3110 seems to be used by
>everyone.
>
>Russel
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Ron Roy on sat 10 may 03
Hi Brenda,
I have gotten behind in my email - do you still need answers on this?
A glaze calculator is a computer program that does the calculating from
recipe to molecular formula.
I use two programs, Insight (http://digitalfire.com) and GlazeMaster by
John Hesselberth (http://www.masteringglazes.com)
Takes some learning but by far the best way to deal with glazes and clay bodies.
Just some of the ways I use them.
Estimate expansion of shiny glazes
Substitute materials in clays and glazes
Solve fit problems
Make original glazes
Make glazes more durable - or less
Make glaze less pridictable - or more
Solve suspension problems
Solve viscosity problems
Just a short list of how I use glaze calculation programs - you will need
to know how to use a program and you will need to understand the function
of each oxide in a glaze. Not something you can learn in a week or two but
well worth the understanding of clay and glazes it brings.
RR
>I am just beginning to mix my own glazes. Actually I have only bought the
>materials. What is a glaze calculator and where do I get one? Am I ready
>for that yet or should I stick with the old faithfuls first?
>
>With cone 10 glazes must I spray, brush or dip. If brushing must the glaze
>be smooth and even as in low fire?
>
>With the toxic glazes do you mean respiratory or contact or both?
>
>Lots of questions---------
>
>Daughter of Clay
>Brenda
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Brenda Anderson on sun 11 may 03
You make it sound so easy. I have ordered several colorants and the basics.
I am ready to start. I have also been collecting "recipes." I went to a
crystalline workshop by Don Holloway in LA and am so excited. It'll
probably take a year or so but am anxious to get started in my new Skutt.
My low fire stuff will be fun pottery but I am moving to the "big boy's
arena." Wish me luck.
Brenda
Daughter of Clay
----- Original Message -----
From: "Ron Roy"
To:
Sent: Saturday, May 10, 2003 9:28 AM
Subject: Re: Glaze materials question for Ron & John
> Hi Brenda,
>
> I have gotten behind in my email - do you still need answers on this?
>
> A glaze calculator is a computer program that does the calculating from
> recipe to molecular formula.
>
> I use two programs, Insight (http://digitalfire.com) and GlazeMaster by
> John Hesselberth (http://www.masteringglazes.com)
>
> Takes some learning but by far the best way to deal with glazes and clay
bodies.
>
> Just some of the ways I use them.
>
> Estimate expansion of shiny glazes
> Substitute materials in clays and glazes
> Solve fit problems
> Make original glazes
> Make glazes more durable - or less
> Make glaze less pridictable - or more
> Solve suspension problems
> Solve viscosity problems
> Just a short list of how I use glaze calculation programs - you will need
> to know how to use a program and you will need to understand the function
> of each oxide in a glaze. Not something you can learn in a week or two but
> well worth the understanding of clay and glazes it brings.
>
> RR
>
>
>
> >I am just beginning to mix my own glazes. Actually I have only bought
the
> >materials. What is a glaze calculator and where do I get one? Am I
ready
> >for that yet or should I stick with the old faithfuls first?
> >
> >With cone 10 glazes must I spray, brush or dip. If brushing must the
glaze
> >be smooth and even as in low fire?
> >
> >With the toxic glazes do you mean respiratory or contact or both?
> >
> >Lots of questions---------
> >
> >Daughter of Clay
> >Brenda
>
> Ron Roy
> RR#4
> 15084 Little Lake Road
> Brighton, Ontario
> Canada
> K0K 1H0
> Phone: 613-475-9544
> Fax: 613-475-3513
>
>
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