Steve Slatin on sun 15 may 05
Dear Marianne --
Admittedly, Bailey is confusing in that sometimes when
a recipe appears, it will say something like "Soda
Feldspar" or "Calcium Borate Frit." From the recipe
pages it's not clear what he means, but at the back of
the book, p. 117 and beyond, he organizes things so
you can find substitutes that will work.
This actually makes Bailey more valuable than a
simpler recipe book, though it's lots harder to use --
For example, in reading his recipes with frits,
sometimes he'll be specific and call for, say, Frit
3110. (If he does, and you're a beginner, don't try
to substitute. It's possible but typically very
difficult.) Maybe he says "Calcium Borate Frit."
Page 119 he shows 4 frits as "Calcium Borate." One is
a US Ferro; Frit 3124. If you go to a frit
substitution page -- there are several on the web, I
use http://mysite.verizon.net/vze778gn/frits.html --
you get the Pemco and Hommel equivalents for 3124.
Now you've got 6 to choose from. Likewise with soda
feldspars and Potash feldspars, he lists several of
each. While they differ somewhat in composition, for
a first try at a glaze it may be worth simply
substituting one-for-one.
It's always a problem when you're starting out to pick
a glaze to work with. One is formulated for the wrong
cone, a second calls for a crash cool and your other
glazes don't respond well, a third requires
ingredients you don't have, a fourth is beautiful but
not food-safe, etc. Take heart! Lots of really great
glazes will work with your procedure, whatever it is
-- and many fine potters have just 3-4 base glazes,
and a few oxide variations.
--- marianne kuiper milks
wrote:
> Hi Steve,
>
> Funny" it was the Michael Bayley book Mastering Cone
> 6
> I used. And it did just say "frit",which was
> terribly
> confusing to me. But I will take your advise re
> meddling and muddle only with things that make
> sense.
> At times I'm not surewhether I'm fiddling with
> Merlin
> or cooking in Hell's Kitchen! Thanks for replying: I
> will be choicy!
>
> Marianne
Steve Slatin --
Sera que ela mexe o chocalho ou o chocalho e que mexe com ela
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marianne kuiper milks on sun 15 may 05
Hi Steve,
Funny" it was the Michael Bayley book Mastering Cone 6
I used. And it did just say "frit",which was terribly
confusing to me. But I will take your advise re
meddling and muddle only with things that make sense.
At times I'm not surewhether I'm fiddling with Merlin
or cooking in Hell's Kitchen! Thanks for replying: I
will be choicy!
Marianne
--- Steve Slatin wrote:
> Marianne --
>
> There are hundreds and hundreds of good glaze
> recipes
> in circulation. If you aren't satisfied with ones
> that actually tell you what to use (and no, all
> frits
> are not created equal) that are posted here, get
> yourself a good book of glaze recipes. Ones I would
> recommend are Val Cushing's handbook (you have to
> mail
> his wife a check, but she sends the handbook back
> really quickly and there's mountains of good info in
> it), Chappell's Clay and Glazes, and if you fire
> cone
> 6 oxidation Bailey's Glazes Cone 6.
>
> If you want to learn how glazes work and get insight
> into how good, reliable glazes are made, and you're
> starting out with cone 6 oxidation I'd consider
> Mastering Cone 6 Glazes an essential book. You
> don't
> get that many actual recipes here, but the ones in
> the
> book are good sturdy bases, and when you know what
> you're doing you can experiment with them.
>
> Other people may have other ideas -- but if you're
> just trying to mix up a glaze and follow a recipe
> and
> the recipe calls for unidentified 'frit' or 'spar'
> or
> the like, I'd strongly advise you not to mess with
> it.
> The likelihood of disappointment is far too high
> compared to the probability of satisfaction.
>
> Best wishes -- Steve Slatin
> --- marianne kuiper milks
>
> wrote:
> > Hello.
> > Thank you (various people) for the information re.
> > kiln/safety etc. Will respond to the rest later.
> > Trying to make / test some recipes, I've run into
> > the
> > problem of not (yet) knowing which chemicals are
> > "the
> > same" or substitutable or major errors. I've
> looked
> > extensively on the internet/Clayart library, but
> > have
> > yet to find the right information on frits.
> > Some can be substituted, as I found, but when it
> > just
> > says "frit", where do I go??? (I only have frit
> > 3134)
> > I realize that I can look up the chemical
> analyses,
> > but when they differ I do not know a good differ
> > from
> > a bad differ. (my chesmistry became rusty about 35
> > years ago).
> > Is there a list (and of others, such as feldspars)
> > somewhere? I'll get there eventually, but for now
> I
> > can't do a thing with it.. Are other chemicals
> > considered frits?
> > Thanks for help! Marianne
> >
> > __________________________________________________
> > Do You Yahoo!?
> > Tired of spam? Yahoo! Mail has the best spam
> > protection around
> > http://mail.yahoo.com
> >
> >
>
______________________________________________________________________________
> > Send postings to clayart@lsv.ceramics.org
> >
> > You may look at the archives for the list or
> change
> > your subscription
> > settings from http://www.ceramics.org/clayart/
> >
> > Moderator of the list is Mel Jacobson who may be
> > reached at melpots@pclink.com.
> >
>
> Steve Slatin --
>
> Sera que ela mexe o chocalho ou o chocalho e que
> mexe com ela
>
>
>
> Yahoo! Mail
> Stay connected, organized, and protected. Take the
> tour:
> http://tour.mail.yahoo.com/mailtour.html
>
>
______________________________________________________________________________
> 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.
>
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Maurice Weitman on mon 16 may 05
At 8:38 PM -0700 on 5/16/05, Steve Slatin wrote:
>"Het is hart-verwarmend dat men vrienden vindt in
>plaatsen waar we niet zoeken"
>It is heart warming that my friends arrive in plaster
>with no socks? Either I'm wrong or that's one of
>those folk-sayings that just doesn't translate.
Although I never wear socks when I'm using plaster (do you???), I
believe that translates to something like:
"It is heart-warming that one finds friends in places where we are
not searching (for them)."
Regards,
Maurice
marianne kuiper milks on mon 16 may 05
Dear Steve,
I took an MB recipe GA12, which I then substituted for GA14, all of which ingredients I have. Subst. P Feldspar for G200 (which Bill Tersteeg, my prof/friend said was fine, then I subst Kaolin/EPK for China clay.
Made a small batch, made a triplicate sets of testtiles and cross-color test tiles. Also used a few useless pieces (chipped, etc, for samples: one of home-made clay, one of Pitt 119 and one Pitt 213 (porcelain) --How am I doing so far? I felt VERY scientific! I divided it all into 4 equal batches and added samples (re-mathed) of the colorants suggested on page 105, to end up with pale green, darker blue-green, light and very dark cobalt.
The other problem was the issue of heat/kiln/cone. I'd ordered free-standing Ortho cones. I placed cones 5,6 and 7 on the bottom, on the middle shelf and the same at the top. A cone 6 in the kiln-sitter. (I felt so "in charge" at this point!
Good morning! Cones 5 were slumped, 6ses were bent over and 7s were contemplating where to go from there. Kiln sitter worked fine.
All glazes were pale and dull vying for lookig exactly like the other. In addition: the glazes peeled off the pottery as if they were window sills on an old house in Tuscany.
A long story, but this step-by-stumble is what happened and I'm not much further other than when I started. I have a B-Victoriad recipe from Bruce Dehnert and will try once more.
If you have the time to send me more suggestions I would certainly appreciate and follow up on them.
Next I will read the frit pages you suggested. Thanks a million!
Marianne
Het is hart-verwarmend dat men vrienden vindt in plaatsen waar we niet zoeken. (Hah!)
Steve Slatin wrote:
Dear Marianne --
Admittedly, Bailey is confusing in that sometimes when
a recipe appears, it will say something like "Soda
Feldspar" or "Calcium Borate Frit." From the recipe
pages it's not clear what he means, but at the back of
the book, p. 117 and beyond, he organizes things so
you can find substitutes that will work.
This actually makes Bailey more valuable than a
simpler recipe book, though it's lots harder to use --
For example, in reading his recipes with frits,
sometimes he'll be specific and call for, say, Frit
3110. (If he does, and you're a beginner, don't try
to substitute. It's possible but typically very
difficult.) Maybe he says "Calcium Borate Frit."
Page 119 he shows 4 frits as "Calcium Borate." One is
a US Ferro; Frit 3124. If you go to a frit
substitution page -- there are several on the web, I
use http://mysite.verizon.net/vze778gn/frits.html --
you get the Pemco and Hommel equivalents for 3124.
Now you've got 6 to choose from. Likewise with soda
feldspars and Potash feldspars, he lists several of
each. While they differ somewhat in composition, for
a first try at a glaze it may be worth simply
substituting one-for-one.
It's always a problem when you're starting out to pick
a glaze to work with. One is formulated for the wrong
cone, a second calls for a crash cool and your other
glazes don't respond well, a third requires
ingredients you don't have, a fourth is beautiful but
not food-safe, etc. Take heart! Lots of really great
glazes will work with your procedure, whatever it is
-- and many fine potters have just 3-4 base glazes,
and a few oxide variations.
--- marianne kuiper milks
wrote:
> Hi Steve,
>
> Funny" it was the Michael Bayley book Mastering Cone
> 6
> I used. And it did just say "frit",which was
> terribly
> confusing to me. But I will take your advise re
> meddling and muddle only with things that make
> sense.
> At times I'm not surewhether I'm fiddling with
> Merlin
> or cooking in Hell's Kitchen! Thanks for replying: I
> will be choicy!
>
> Marianne
Steve Slatin --
Sera que ela mexe o chocalho ou o chocalho e que mexe com ela
__________________________________
Yahoo! Mail Mobile
Take Yahoo! Mail with you! Check email on your mobile phone.
http://mobile.yahoo.com/learn/mail
______________________________________________________________________________
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.
---------------------------------
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Stay connected, organized, and protected. Take the tour
Steve Slatin on mon 16 may 05
Marianne --
OK, let's start at the bottom and work backwards.
It's not any language I speak, or French or Latin or
even German, lemme see ... might be Dutch, but I don't
speak any Dutch, still, to take a crack at it --
"Het is hart-verwarmend dat men vrienden vindt in
plaatsen waar we niet zoeken"
It is heart warming that my friends arrive in plaster
with no socks? Either I'm wrong or that's one of
those folk-sayings that just doesn't translate. (I'm
a language dummy who spent 20 years living mostly in
other countries and the last 10 in a multi-lingual
household, so I'm used to being wrong. And to things
not translating.*)
From your description I'd guess your glaze was
'immature' -- mixed so that it'd have taken more heat
work than it got to fully vitrify.
Bailey's GA12 is actually Tony Hansen's 5 x 20, a
subject about which I have recently shown myself to be
more than moderately ignorant (though I've used the
glaze, and it's great). GA14 is a reformulation to
use UK frits.
Now, I'm not 100% clear on what you were mixing, but
I'm presuming you used the percentages in GA14 with
the spar and frit from GA14.
If I am wrong and you used the 5 x 20 amounts and the
spar and frit from GA14, that was likely your problem.
The percentages in GA14 call for more borate-rich frit
and less china clay. This is the direction to lean in
to make a glaze shinier (if possibly a bit runnier).
The issue with GA14 is that it's not a particularly
exact reformulation of GA12 -- for example, GA14 has
20.16% total fluxes vs. 22.23 for 5 x 20, and only
3.95 boron vs. 4.47 (B2O3). (At cone 6 boron is
largely melter. For higher temperatures, it's more
often used as a glass former.) Also, it's got less
alumina and a higher silica/alumina ratio. (This
seems to be how Bailey makes it work with less flux.)
With the percentages for GA12 and the materials
specified for GA14, you get only 19% flux, 3.33
percent boron, and more alumina. It no longer looks
like a Cone 6 glaze.
Then we get your individual substitutions from the
GA14 recipe. EPK for china clay normally should be no
problem. EPK is one of the many kaolins commonly used
by potters. There are a few kaolins that are somewhat
different (like Tile #6) but most potters will
substitute grolleg, helmer, and EPK pretty freely.
Look at the analyses on pps. 117-118 of Bailey, though
-- his N50 China Clay and the EPK do differ in that
EPK has more alumina and less silica.
Next, we look at the feldspar substitution. G-200 is
a potash feldspar, and the analysis of Bailey's P-spar
and G-200 are close. One difference is that G-200 has
about 1.5% more alumina ... see where we're going?
Unfortunately, every step you took, albeit small, was
away from the target you started with.
Now on heat, it's not entirely clear if you got a good
Cone 6 firing. How far over were the cone 6 cones? A
180 degree bend, with the tip of the cone almost
touching the shelf is what I try to get. It's
possible that you got a bend and the cone is pointing
out horizontally, which is a fractional cone below
your heat work target. Many glazes will work at this
(cone 5 1/2 or 5 2/3 or whatever) but not all will.
If your tips were practically touching (or touching
the kiln shelf) then you were at that cone or above
it. If that was the case, we're back to looking at
the glaze and if you had enough melters.
To put this ramble together --
First, look at your cones. Did you make cone? If
not, put those same cones back in (they've got the
heat work in them that your work has) and refire until
cone 6 is down. That might solve your problem.
Next, if the cones are OK, check your ware. Are some
sides of some pots pretty well vitrified, and others a
mess? If so, it could have been heat distribution
inside your kiln. For glaze firing you need a bit of
space between pieces so the hot air can circulate. If
the pots that were on the outside rim of your shelves
fired properly on the side next to the elements. The
solution is to load the kiln again with fewer pieces
and adequate ventilation space, and refire.
Now, if your cone 6 cones were all tip down to the
shelf and your pots are uniformly unacceptable, you're
pretty much secure in thinking the glaze is the
problem. Take heart, you've got a known problem with
an obvious solution -- you didn't melt, you need more
melters, and to get there you need to add more of the
ingredient -- the frit -- that bears the most melters.
So how much frit do you add? That's a problem; but in
my experience getting the frit within 2% of the target
amount will generally give you some kind of a good
glaze. My solution for you would be to add 2% of the
total amount of your dry ingredients, test on a single
tile or whatever, and, if it doesn't work, add another
2%. (Because the frits have other materials besides
melters, you're adding much less than 2% melters with
each experiment.) If you know how to do a line blend
you could do that, and get several sample
concentrations of additional frit tested at one time.
Sorry it didn't work well for you. Best wishes --
Steve Slatin
I'm lazy, I'd just do it one whack at a time, and stop
when the glaze began to mature.
*(From all of this there's really only one thing I
learned -- never ask an Iranian, Afghan, or Tajik cook
if they know how to make cous-cous. Don't ask why,
just trust me on this.)
--- marianne kuiper milks
wrote:
> Dear Steve,
>
> I took an MB recipe GA12, which I then substituted
> for GA14, all of which ingredients I have. Subst. P
> Feldspar for G200 (which Bill Tersteeg, my
> prof/friend said was fine, then I subst Kaolin/EPK
> for China clay.
> Made a small batch, made a triplicate sets of
> testtiles and cross-color test tiles. Also used a
> few useless pieces (chipped, etc, for samples: one
> of home-made clay, one of Pitt 119 and one Pitt 213
> (porcelain) --How am I doing so far? I felt VERY
> scientific! I divided it all into 4 equal batches
> and added samples (re-mathed) of the colorants
> suggested on page 105, to end up with pale green,
> darker blue-green, light and very dark cobalt.
>
> The other problem was the issue of heat/kiln/cone.
> I'd ordered free-standing Ortho cones. I placed
> cones 5,6 and 7 on the bottom, on the middle shelf
> and the same at the top. A cone 6 in the
> kiln-sitter. (I felt so "in charge" at this point!
>
> Good morning! Cones 5 were slumped, 6ses were bent
> over and 7s were contemplating where to go from
> there. Kiln sitter worked fine.
> All glazes were pale and dull vying for lookig
> exactly like the other. In addition: the glazes
> peeled off the pottery as if they were window sills
> on an old house in Tuscany.
>
> A long story, but this step-by-stumble is what
> happened and I'm not much further other than when I
> started. I have a B-Victoriad recipe from Bruce
> Dehnert and will try once more.
>
> If you have the time to send me more suggestions I
> would certainly appreciate and follow up on them.
> Next I will read the frit pages you suggested.
> Thanks a million!
>
> Marianne
>
> Het is hart-verwarmend dat men vrienden vindt in
> plaatsen waar we niet zoeken. (Hah!)
Steve Slatin --
Some men will do here for diamonds what some men will do here for gold
__________________________________
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Read only the mail you want - Yahoo! Mail SpamGuard.
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gjudson on tue 17 may 05
Steve, Thank you so much for the time and thought you put into =
responding
to my question. You have offered a lot for me think about and try to =
hang
onto! Actually, I am surprised that I am not discouraged by all that I =
need
to try to master--instead I am challenged to just do it. I feel like =
the
Little Red Engine, "I think I can, I think I can, I think I can."
At this point, I am just trying to successfully mix-up and fire glazes =
that
I like! But I want to understand what is happening so I can figure =
out--or
know where to find out--what substitutions or changes I can make safely.
Thanks again for the help--you'll probably be hearing more from me soon!
Either with report of good results or more questions! =20
Gay Judson in San Antonio, TX=20
gjudson on tue 17 may 05
Steve and Marianne,
I am following this conversation closely as I am in very much the same =
spot
as Marianne. Steve's analysis and recommendations are just what I need
right now, too. =20
So the question that comes to mind, for me just now, is about using the
GlazeMaster program to spot these adjustments. I am about to substitute =
EPK
for China clay. If I compare the analysis of the two recipes--the =
original
and the one in which I exchanged the EPK for China clay--what do I look =
for?
And will I ever learn enough about these materials to know off the cuff =
what
they do in the glaze? I working on it--but starting all this after
retirement may be asking more of a declining memory system than it can
handle.
Thanks for all the good helps, all! Gay Judson, San Antonio, TX =20
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Steve =
Slatin
Sent: Monday, May 16, 2005 10:39 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Frits to Steve:
Marianne --
OK, let's start at the bottom and work backwards.
It's not any language I speak, or French or Latin or
even German, lemme see ... might be Dutch, but I don't
speak any Dutch, still, to take a crack at it --
"Het is hart-verwarmend dat men vrienden vindt in
plaatsen waar we niet zoeken"
It is heart warming that my friends arrive in plaster
with no socks? Either I'm wrong or that's one of
those folk-sayings that just doesn't translate. (I'm
a language dummy who spent 20 years living mostly in
other countries and the last 10 in a multi-lingual
household, so I'm used to being wrong. And to things
not translating.*)
From your description I'd guess your glaze was
'immature' -- mixed so that it'd have taken more heat
work than it got to fully vitrify.
Bailey's GA12 is actually Tony Hansen's 5 x 20, a
subject about which I have recently shown myself to be
more than moderately ignorant (though I've used the
glaze, and it's great). GA14 is a reformulation to
use UK frits.
Now, I'm not 100% clear on what you were mixing, but
I'm presuming you used the percentages in GA14 with
the spar and frit from GA14.
If I am wrong and you used the 5 x 20 amounts and the
spar and frit from GA14, that was likely your problem.
The percentages in GA14 call for more borate-rich frit
and less china clay. This is the direction to lean in
to make a glaze shinier (if possibly a bit runnier).
The issue with GA14 is that it's not a particularly
exact reformulation of GA12 -- for example, GA14 has
20.16% total fluxes vs. 22.23 for 5 x 20, and only
3.95 boron vs. 4.47 (B2O3). (At cone 6 boron is
largely melter. For higher temperatures, it's more
often used as a glass former.) Also, it's got less
alumina and a higher silica/alumina ratio. (This
seems to be how Bailey makes it work with less flux.)
With the percentages for GA12 and the materials
specified for GA14, you get only 19% flux, 3.33
percent boron, and more alumina. It no longer looks
like a Cone 6 glaze.
Then we get your individual substitutions from the
GA14 recipe. EPK for china clay normally should be no
problem. EPK is one of the many kaolins commonly used
by potters. There are a few kaolins that are somewhat
different (like Tile #6) but most potters will
substitute grolleg, helmer, and EPK pretty freely.
Look at the analyses on pps. 117-118 of Bailey, though
-- his N50 China Clay and the EPK do differ in that
EPK has more alumina and less silica.
Next, we look at the feldspar substitution. G-200 is
a potash feldspar, and the analysis of Bailey's P-spar
and G-200 are close. One difference is that G-200 has
about 1.5% more alumina ... see where we're going?
Unfortunately, every step you took, albeit small, was
away from the target you started with.
Now on heat, it's not entirely clear if you got a good
Cone 6 firing. How far over were the cone 6 cones? A
180 degree bend, with the tip of the cone almost
touching the shelf is what I try to get. It's
possible that you got a bend and the cone is pointing
out horizontally, which is a fractional cone below
your heat work target. Many glazes will work at this
(cone 5 1/2 or 5 2/3 or whatever) but not all will.
If your tips were practically touching (or touching
the kiln shelf) then you were at that cone or above
it. If that was the case, we're back to looking at
the glaze and if you had enough melters.
To put this ramble together --
First, look at your cones. Did you make cone? If
not, put those same cones back in (they've got the
heat work in them that your work has) and refire until
cone 6 is down. That might solve your problem.
Next, if the cones are OK, check your ware. Are some
sides of some pots pretty well vitrified, and others a
mess? If so, it could have been heat distribution
inside your kiln. For glaze firing you need a bit of
space between pieces so the hot air can circulate. If
the pots that were on the outside rim of your shelves
fired properly on the side next to the elements. The
solution is to load the kiln again with fewer pieces
and adequate ventilation space, and refire.
Now, if your cone 6 cones were all tip down to the
shelf and your pots are uniformly unacceptable, you're
pretty much secure in thinking the glaze is the
problem. Take heart, you've got a known problem with
an obvious solution -- you didn't melt, you need more
melters, and to get there you need to add more of the
ingredient -- the frit -- that bears the most melters.
So how much frit do you add? That's a problem; but in
my experience getting the frit within 2% of the target
amount will generally give you some kind of a good
glaze. My solution for you would be to add 2% of the
total amount of your dry ingredients, test on a single
tile or whatever, and, if it doesn't work, add another
2%. (Because the frits have other materials besides
melters, you're adding much less than 2% melters with
each experiment.) If you know how to do a line blend
you could do that, and get several sample
concentrations of additional frit tested at one time.
Sorry it didn't work well for you. Best wishes --
Steve Slatin
I'm lazy, I'd just do it one whack at a time, and stop
when the glaze began to mature.
*(From all of this there's really only one thing I
learned -- never ask an Iranian, Afghan, or Tajik cook
if they know how to make cous-cous. Don't ask why,
just trust me on this.)
--- marianne kuiper milks
wrote:
> Dear Steve,
>
> I took an MB recipe GA12, which I then substituted
> for GA14, all of which ingredients I have. Subst. P
> Feldspar for G200 (which Bill Tersteeg, my
> prof/friend said was fine, then I subst Kaolin/EPK
> for China clay.
> Made a small batch, made a triplicate sets of
> testtiles and cross-color test tiles. Also used a
> few useless pieces (chipped, etc, for samples: one
> of home-made clay, one of Pitt 119 and one Pitt 213
> (porcelain) --How am I doing so far? I felt VERY
> scientific! I divided it all into 4 equal batches
> and added samples (re-mathed) of the colorants
> suggested on page 105, to end up with pale green,
> darker blue-green, light and very dark cobalt.
>
> The other problem was the issue of heat/kiln/cone.
> I'd ordered free-standing Ortho cones. I placed
> cones 5,6 and 7 on the bottom, on the middle shelf
> and the same at the top. A cone 6 in the
> kiln-sitter. (I felt so "in charge" at this point!
>
> Good morning! Cones 5 were slumped, 6ses were bent
> over and 7s were contemplating where to go from
> there. Kiln sitter worked fine.
> All glazes were pale and dull vying for lookig
> exactly like the other. In addition: the glazes
> peeled off the pottery as if they were window sills
> on an old house in Tuscany.
>
> A long story, but this step-by-stumble is what
> happened and I'm not much further other than when I
> started. I have a B-Victoriad recipe from Bruce
> Dehnert and will try once more.
>
> If you have the time to send me more suggestions I
> would certainly appreciate and follow up on them.
> Next I will read the frit pages you suggested.
> Thanks a million!
>
> Marianne
>
> Het is hart-verwarmend dat men vrienden vindt in
> plaatsen waar we niet zoeken. (Hah!)
Steve Slatin --
Some men will do here for diamonds what some men will do here for gold
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marianne kuiper milks on tue 17 may 05
Hey Maurice, (Flemish???)
I am impressed! And pleasedthat someone knows/can
figure out Dutch. Or you have friends in strange
places.
I agree about the socks, but I'd object more to the
plaster - particularly into my little studio!
Re. the Flemish: someone asked me once to say
something in Dutch. A friend then thought that perhaps
it sounded like Flemish. Responding to the rather
gutteral sounds, the first person said "Well, it all
sounds rather phlegmish to me!" (This is a true story)
Have a sunny one, Marianne
--- Maurice Weitman wrote:
> At 8:38 PM -0700 on 5/16/05, Steve Slatin wrote:
> >"Het is hart-verwarmend dat men vrienden vindt in
> >plaatsen waar we niet zoeken"
> >It is heart warming that my friends arrive in
> plaster
> >with no socks? Either I'm wrong or that's one of
> >those folk-sayings that just doesn't translate.
>
> Although I never wear socks when I'm using plaster
> (do you???), I
> believe that translates to something like:
>
> "It is heart-warming that one finds friends in
> places where we are
> not searching (for them)."
>
> Regards,
> Maurice
>
>
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Edouard Bastarache Inc. on tue 17 may 05
Hello Steve,
it sounds like Dutch
"Het is hart-verwarmend dat men vrienden vindt in plaatsen waar we niet
zoeken"=
It is heart heating that one finds friends in places where we do not
"zoeken"
I have just asked the help of Stefan Van Cleemput, co-author of The
Multilingual
Dictionary of Pottery Words.
Later,
"Ils sont fous ces quebecois"
"They are insane these quebekers"
"Están locos estos quebequeses"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
www.sorel-tracy.qc.ca/~edouardb/Welcome.html
http://perso.wanadoo.fr/smart2000/index.htm
http://www.digitalfire.com/education/toxicity/
Steve Slatin on tue 17 may 05
Gay --
You do know I'm just a tinkerer, right? (Any of you
actual glaze gurus want to jump in here, feel free. I
know how little I know, I hope people who read what I
write understand that.)
Lili's long post on glaze is a good place to start.
Some people find Rhodes' book the best; I learned from
that first, years ago. It's dry, though, and makes
the process more complex than it has to be. I already
knew how to do molar calculations and after a few
hours with Rhodes I knew what he was getting at and I
decided to get there by myself. (I still stick with
molar calculations for that reason.)
Part of the problem is getting your head around what's
happening, but part is in the fact that some materials
react differently at different temperatures and
atmospheres. Rhodes has a sort of preferential tilt
towards cone 10. If you're working with Cone 6
oxidation, lean on Mastering Cone 6 Glazes, it's
easier to follow and tilts towards your materials.
I only work at cone 6 oxidation, so my understanding
is limited to that. It also shows in my preference
for amount of silica; I use boron in most of my glazes
so I tend to prefer somewhat less silica in my glaze
than you might otherwise see.
In absolute honesty, if I'm trying a recipe and it
calls for china clay, I start with a one-for-one sub
of EPK. If it doesn't work in a test batch, then I
look for hints in different analyses. If you're
working from Bailey's Glazes Cone 6, you can use his
analyses; if not, it's kind of hard to know what a
glaze formulator means when they say "China clay."
It's not like there's an absolute standard for china
clay ... Hamer and Hamer describe it as being
approximately equal to kaolinite, which is Al2O3 *
2(SiO2) * 2(H2O). There's also an agreement that
kaolin has very little iron or titanium. But there
are some differences between kaolins, as they have
differing plasticity, etc. If you don't know that the
glaze creator was using something else, there's a
possibility that their "china clay" was EPK anyway
(especially if they're located in North America).
That meandering aside, since you're using calc
software, use it and see -- Glaze Master has that
split-screen mode where you can compare two glazes and
work on one; set up two versions of the glaze you're
interested in, one original and one to work on, fill
in all materials, and look at the differences.
You should always check the total fluxes. (This is
harder to see in Seger format; if you switch to weight
or mole analysis, it's obvious.) All fluxes are not
equal, but if you're more-or-less in the ballpark on
the total, you'll likely still get a good melt.
For cone 6 you must also look at the boron amount as a
flux. At ^6 it's a strong flux, so make sure you're
close here or you may have a problem. Lots of cone 6
glazes work out to be roughly 1/4 fluxes when you
include boron.
I've never seen too much difference between two
versions of the same glaze where the big difference is
one has more sodium and the other more potassium. I
add them together and if together they're about the
same, I don't worry about that. The percentage of your
flux that is Sodium plus Potassium vs. that which is
Calcium seems to have a lot to do with variagation in
glazes. Keeping the relative amounts of these two
fluxes roughly the same may help achieve roughly the
same results. There will be differences also if you
have, for example, more magnesium and less calcium,
but it will probably be in effect, in either case
you'll have a fairly usable glaze (i.e., the
differences will be artistic/aesthetic rather than
functional).
The other two parts of a base glaze are silica and
alumina. The ratio of the two is important in making
a glaze, but you also need sufficient glass formers to
make a stable, sturdy glaze. Check your version of
the glaze against the original to see what's going on
in terms of the Si/Al ratio. Your glossies will have
more parts Si for each Al, the semi-mattes will be
lower, and by the time you're at five parts to one you
likely have a glaze so rough it's not suitable for
food. Switch to the limit formula screen to look at
the totals of Si and Al. Being close to exact on both
will of course be a sure way of getting a similar
result.
If you're off in results, look at the glass-former
total compared to the Al amount -- boron, silica,
phosphorous, selenium -- these are all glass-formers.
Usually the last two aren't in glazes in significant
percentages, but if they are, they could be important
in effect.
Now look at other things in your glaze that may have
fluxing/refractory results. Cobalt is a powerful
flux, zirconium (found in zircopax, superpax, etc.) is
refractory, I don't know what else you may be putting
in your glazes.
Here's the other thing -- with the exception of a few
expecially reactive elements (boron, cobalt, etc.) you
can mix your glaze and be 1% off in the mix and never
even know it (visually, anyway).
The ingredients you use to get to a recipe typically
are already mixes. Feldspars have silica and alumina.
Clays have silica and alumina. Frits have silica and
alumina. So being a good bit more than a percent off
in the ingredients in you mix may leave you still in a
safe range for your glaze.
Marianne's problem was special -- she got into a
recipe, did a few substitutions either of which
probably shouldn't have made a difference, and she
ended up with an unusable result. Maybe temperature
was a part of the problem, maybe she was off on a
measurement, maybe because the substitutions were all
towards alumina and away from silica that was the
problem ... it's hard to say.
What we do know is the more popular glazes, like
Hansen's 5 x 20, can be mixes a little casually or
have one or another item substituted and generally
come out OK. When it doesn't adding a bit of clay if
it's too runny or flux if it's too 'dry' will often
bring you back to a decent looking glaze. Then all
you have to do is try a lemon test or two on it, and
you can be in your comfort zone -- well, at least my
comfort zone.
Best wishes -- Steve S.
--- gjudson wrote:
> Steve and Marianne,
> I am following this conversation closely as I am in
> very much the same spot
> as Marianne. Steve's analysis and recommendations
> are just what I need
> right now, too.
>
> So the question that comes to mind, for me just now,
> is about using the
> GlazeMaster program to spot these adjustments. I am
> about to substitute EPK
> for China clay. If I compare the analysis of the
> two recipes--the original
> and the one in which I exchanged the EPK for China
> clay--what do I look for?
>
> And will I ever learn enough about these materials
> to know off the cuff what
> they do in the glaze? I working on it--but starting
> all this after
> retirement may be asking more of a declining memory
> system than it can
> handle.
>
> Thanks for all the good helps, all! Gay Judson, San
> Antonio, TX
Steve Slatin --
Some men will do here for diamonds what some men will do here for gold
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gjudson on wed 18 may 05
> -----Original Message-----
> From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Steve =
Slatin
> Sent: Tuesday, May 17, 2005 1:53 PM
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Re: Frits to Steve:
Steve wrote:
> Lili's long post on glaze is a good place to start.
I remember reading--and saving SOMEWHERE--a post Lili made on making =
glazes
some time back and I thought that was what Steve was referring to. So I
spent several hours this morning going through the archives for the last =
2
1/2 years reading Lili's posts related to glazes. Never found what I =
was
looking for. But when I got to the April 2005 section of the archives I
found what Steve was referring to! I had been "no mail" for a while =
this
spring and had missed that contribution. Wonderful! Thanks Lili and =
thanks
again Steve! =20
Gay Judson in San Antonio, TX
MAY LUK on wed 18 may 05
Hi all;
FYI: The frits & materials in Mike Bailey's book - you
can find the analysis at http://www.bathpotters.co.uk/
In the UK, material names are simplier. They are
called merely Calcium Borate Frits or Soda Feldspar -
just like that. There are only 4 types of Ferro Frits
[also listed at Bath Potters Supplies web site] They
are not used often because they are much more
expensive.
If you want most of the materials analysis on a
spreadsheet [US and UK together] Please email me and I
can post it to you. I had spent some time to lay them
out for my own reference.
Regards
May
yamerica at btopenworld dot com
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