Burtt on wed 17 feb 99
I could use some help with a glaze question. Recently, I was testing
four cone 6 glazes. One of them worked, a nice light green. The other
three, two greens and a red (which is always brown in my kiln), were not
exactly what I wanted.
So, I dumped the three no-go glazes together just for the fun of it.
However, I thought the red would overpower the two green glazes, so I
only dumped in SOME of the red. I don't know how much.
You can guess the rest of this story. I came up with a glaze I
really like, a nice subtle but rich blue, and now I can't figure out how
to reproduce it.
Is there an answer to this one?
The Buchanans on thu 18 feb 99
You've been playing my game so maybe I can give you some hints. First, list =
and
combine the ingredients in the two green glazes. Do the math and get the per
centages.( devide the amount of each by the total) This will let you make a =
100
gram batch to test. Now the red glaze, I bet you know if you dumped in less =
than
half, or a quarter or eighth. I would probably make a 50 gram batch of the =
red
and starting with 5 grams(10=25) add it to the green glaze . Dip a tile and =
add 5g
more , repeating until I thought I had more red in than the good test had .
Fire , if , if I say , any of the tests are close, do the math. how much of
each chemical is in the multiple of 5gs you used. add them to the 100 gram
recipe and refigure for percentages . Next time mesure and keep records.
Generally you can figure 100 grams is 3/4 of a cup of liquid glaze, to =
give a
place to start guessing from.
Judi B.
Thonas C. Curran on thu 18 feb 99
Burtt wrote:
>
> ----------------------------Original message----------------------------
> I could use some help with a glaze question. Recently, I was testing
> four cone 6 glazes. One of them worked, a nice light green. The other
> three, two greens and a red (which is always brown in my kiln), were not
> exactly what I wanted.
> So, I dumped the three no-go glazes together just for the fun of it.
> However, I thought the red would overpower the two green glazes, so I
> only dumped in SOME of the red. I don't know how much.
> You can guess the rest of this story. I came up with a glaze I
> really like, a nice subtle but rich blue, and now I can't figure out how
> to reproduce it.
> Is there an answer to this one?
Burtt: I have made triaxial blends of 3 separate copper red glazes to
see what new glaze effects I might come up with. These I did by volume
with wet glazes already made up, using plastic cups to hold each glaze
sample and either a coffee measurer or tablespoon (forget which) to
measure with. Test tiles were then dipped once into each glaze, then
dipped again over 1/2 the area in order to give rough idea of both thin
and thick coats. Of course this method is not an accurate test, but it
will allow you to easily test the whole range of possibilities. (I also
put a wash of iron oxide on the back of the stand-up tiles to give a
further experiment with little extra work. Then, you take the most
promising results and play around with them. The triaxial blend in
gradations of 10% will give you a lot of variety (and a lot of test
tiles), or you could begin with a triaxial blend with larger increments
and fewer tiles. Any questions? You'll find info on triaxial blends in
some of the basic ceramics textbooks if you're not familiar with doing
them, and the name is more impressive than the procedure, so don't be
scared off. Who knows? You may end up with a whole range of glazes you
like better than the original. Good luck from Carolyn, who hopes we do
not get the big snowstorm predicted for later this week...PS What were
the original recipes? Any cobalt in the recipes? If not,
rutile,titanium, nickel,chrome, copper, iron? Inquiring minds want to
know...
Kurt Wild on thu 18 feb 99
I have done the same thing many times. My rule of thumb is that
apporimately 1/2 cup of liquid glaze equals 100 grams of dry glaze.
That is NO HELP UNLESS you know how many cups of each glaze was dumped
into the bucket. If, as an example, there were three half cups of
liquid glaze A and three half cups of liquid glaze B and one half cup
of liquid glaze C you would multiply the recipe of glaze A by 3, glaze B
by 3 and glaze C by 1. Next you would total the amount of each
ingredient from all of the cups from all three glazes and dived each
ingredient by 7 (the number of half cups of glaze in your mystery
glaze). Then you would simply add up those amounts and you should have
the 100% recipe.
Again, if you don't know how many half cups you dumped, you might
meassure the whole bucket and estimate the amount of each and then
follow my suggestion above.
Make sense? I hope it does.
--
Kurt Wild
1000 E. Cascade Ave.
River Falls, WI 54022
Phone: 715-425-5715
email: kurt.l.wild@uwrf.edu
web site: http://wwwpp.uwrf.edu/~kw77/
Bonita Cohn on thu 18 feb 99
*Burtt wrote: I dumped the three no-go glazes together just for the fun.*
Fun, indeed! This unknown combination could be a lucky break for your ceramic
education. If you take the time. You have a situation that can be understood
by looking at the tri-axial blend diagram found in many books that teach glaze
calculation--Rhodes, Petersen's Craft+Art of Clay, Val's Handbook, etc.
Mainly, each glaze is one corner of a triangle, pure. Make up 3 small batches
of your glazes. Make up test tiles, number the order, etc. Try combos of the
three until you repeat your results. Great rainy day activity. If the bases
are the same, and the color is all your looking for, try testing the colorants
the same way.
D. McDysan on thu 19 oct 00
Is it possible to have a glaze analyzed and get the recipe? Who does this
and how much does it cost?
Debbie McDysan
Steve Burtt on sat 7 sep 02
Wonder if I could get a little help with a glaze problem? I made a mistake when mixing a bucket of butterscotch and the result was really nice, but I do not know what I did to it.
Here's the original glaze: Butterscotch:
Custer Feldspar 28
Frit 3134 32
EPK 14
Silica 19
Whiting 7
Rutile 4
This glaze makes a glossy, translucent butterscotch that gets creamy and white when thick. The strange bucket that I made up came out opaque, semi-glossy, and thick; did not go white when thick.
My original thought was that I used G200 instead of Custer, but I did a test and G200 does not make a noticable difference.
I am perfectly willing to do some testing if someone can tell me what I might have added too much or too little of.
Thanks.
Steve Burtt
Ocean Springs, Mississippi
Lily Krakowski on sun 8 sep 02
From what you say you made the glaze more refractory. You raised its melting
point.
That suggests you omitted a flux. You may have left out the whiting
entirely.If you weigh out your ingredients in their order on your list, you
may have forgotten to RESET your scale from 28 to 32, and have too little
frit.
My suggestion--that WHILE LETTING THE GLAZE IN THE BUCKET DRY OUT ENTIRELY
you make some tests. Straight line blends. Leave out all whiting in one
test, all spar in another, all frit in a third.
When the tests are done and the clay-in-bucket bone dry weigh the dried
glaze so you can add the right amount of whatever. Good luck
Steve Burtt writes:
> Wonder if I could get a little help with a glaze problem? I made a mistake when mixing a bucket of butterscotch and the result was really nice, but I do not know what I did to it.
>
> Here's the original glaze: Butterscotch:
> Custer Feldspar 28
> Frit 3134 32
> EPK 14
> Silica 19
> Whiting 7
> Rutile 4
>
> This glaze makes a glossy, translucent butterscotch that gets creamy and white when thick. The strange bucket that I made up came out opaque, semi-glossy, and thick; did not go white when thick.
> My original thought was that I used G200 instead of Custer, but I did a test and G200 does not make a noticable difference.
> I am perfectly willing to do some testing if someone can tell me what I might have added too much or too little of.
> Thanks.
>
> Steve Burtt
> Ocean Springs, Mississippi
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
Lili Krakowski
P.O. Box #1
Constableville, N.Y.
(315) 942-5916/ 397-2389
Be of good courage....
clifton wood on sun 8 sep 02
hi, steve.
i'm sure you'll get a quick answer to your glaze mystery, but just in case you
don't....
i'm a recent convert to ian currie's glaze exploration method.
seems to me (as a rabid novice) that this would be a swell answer to your problem.
the hardest part is making a 35 compartment tile... but you could use 35 test tiles,
numbered... or just roll out a slab and make a 5x7 grid of 35 thumb prints (damn,
why didn't i think of this before? o, because i want the PPA to award me the most
gorgeous original anal tile ribbon.)
just take your original recipe & enter it in ian's web site. it will calculate 35
variants of your glaze, varying ingredients.
it also gives you 4 "corner" glazes, and the directions to use these 4 to mix the
other 31.
it sounds like a lot of work... but aside from making the tiles, i find it's a ton of
fun. all you really need is 35 small containers - i use pee cups... the kind from
the doctor. and a syring or kiddie liquid medicine dispenser...$2 from the pharmacy.
all the rest of the recommended supplies are helpful if doing lots of experiments -
graduated cylinder, etc - are nice, but not necessary for your single foray.
i'm probably telling all this to someone who's used ian's method for years. owell,
as i said, i'm a recent rabid convert.
i'm so glad someone else will come up with a great, short answer, and i can be
embarrassed and once again slink off to lurker status.
won't someone please ask a question about rochester new york so that i can give a
brief, correct answer for a change? i long to appear brilliant to my fellow clay
arters. sigh.
Ian Macmillan on sun 8 sep 02
Steve,
One thing that would change the surface a bit would be if you
reversed the EPK and the silica, lowering the Si/Al ratio to less
gloss???
Good luck,
Ian
>Wonder if I could get a little help with a glaze problem? I made a
>mistake when mixing a bucket of butterscotch and the result was
>really nice, but I do not know what I did to it.
>
> Here's the original glaze: Butterscotch:
> Custer Feldspar 28
> Frit 3134 32
> EPK 14
> Silica 19
> Whiting 7
> Rutile 4
>
> This glaze makes a glossy, translucent butterscotch that gets
>creamy and white when thick. The strange bucket that I made up came
>out opaque, semi-glossy, and thick; did not go white when thick.
> My original thought was that I used G200 instead of Custer, but
>I did a test and G200 does not make a noticable difference.
> I am perfectly willing to do some testing if someone can tell me
>what I might have added too much or too little of.
> Thanks.
>
>Steve Burtt
>Ocean Springs, Mississippi
>
>______________________________________________________________________________
>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.
Ned Ludd on sun 8 sep 02
Hi Lily
Instead of taking all the time and trouble to render a wet glaze back
to bone dry in order to determine its dry weight, why not use
Brongniart's Formula?
What it does is determine the dry weight of the ingredients in a wet
slop: slip or glaze. To work the formula all you need is the relatve
density of the glaze, and an accurate volume of same. Take out your
electronic calculator and off you go.
The Hamer Dictionary has an comprehensive entry on Brongniart's
Formula: my copy is away at the studio, or I'd cite it here.
I'd be interested to learn if any other Clayarter uses this method.
best
Ned
Lily Krakowski wrote
>My suggestion--that WHILE LETTING THE GLAZE IN THE BUCKET DRY OUT ENTIRELY
>you make some tests. Straight line blends. Leave out all whiting in one
>test, all spar in another, all frit in a third.
>
>When the tests are done and the clay-in-bucket bone dry weigh the dried
>glaze so you can add the right amount of whatever. Good luck
>
>
>Steve Burtt writes:
>
>> Wonder if I could get a little help with a glaze problem? I made a
>>mistake when mixing a bucket of butterscotch and the result was
>>really nice, but I do not know what I did to it.
>>
>> Here's the original glaze: Butterscotch:
>> Custer Feldspar 28
>> Frit 3134 32
>> EPK 14
>> Silica 19
>> Whiting 7
>> Rutile 4
>>
>> This glaze makes a glossy, translucent butterscotch that gets
>>creamy and white when thick. The strange bucket that I made up came
>>out opaque, semi-glossy, and thick; did not go white when thick.
>> My original thought was that I used G200 instead of Custer,
>>but I did a test and G200 does not make a noticable difference.
>> I am perfectly willing to do some testing if someone can tell
>>me what I might have added too much or too little of.
>> Thanks.
>>
>> Steve Burtt
> > Ocean Springs, Mississippi
Lily Krakowski on sun 8 sep 02
There is something unbelievably wonderful in a Ned Ludd suggesting formulae
and stuff. It made my day evern better!
But, Ned, my method is SO simple. Put the glaze in a big shallow pan, while
it is drying sort of stir it,so it dries more quickly and voila.
Many thanks. I will look uyp the formula so I know it.
Ned Ludd writes:
> Hi Lily
>
> Instead of taking all the time and trouble to render a wet glaze back
> to bone dry in order to determine its dry weight, why not use
> Brongniart's Formula?
>
> What it does is determine the dry weight of the ingredients in a wet
> slop: slip or glaze. To work the formula all you need is the relatve
> density of the glaze, and an accurate volume of same. Take out your
> electronic calculator and off you go.
>
> The Hamer Dictionary has an comprehensive entry on Brongniart's
> Formula: my copy is away at the studio, or I'd cite it here.
>
> I'd be interested to learn if any other Clayarter uses this method.
>
> best
>
> Ned
>
>
>
> Lily Krakowski wrote
>
>
>> My suggestion--that WHILE LETTING THE GLAZE IN THE BUCKET DRY OUT
>> ENTIRELY
>> you make some tests. Straight line blends. Leave out all whiting in one
>> test, all spar in another, all frit in a third.
>>
>> When the tests are done and the clay-in-bucket bone dry weigh the dried
>> glaze so you can add the right amount of whatever. Good luck
>>
>>
>> Steve Burtt writes:
>>
>>> Wonder if I could get a little help with a glaze problem? I made a
>>> mistake when mixing a bucket of butterscotch and the result was
>>> really nice, but I do not know what I did to it.
>>>
>>> Here's the original glaze: Butterscotch:
>>> Custer Feldspar 28
>>> Frit 3134 32
>>> EPK 14
>>> Silica 19
>>> Whiting 7
>>> Rutile 4
>>>
>>> This glaze makes a glossy, translucent butterscotch that gets
>>> creamy and white when thick. The strange bucket that I made up came
>>> out opaque, semi-glossy, and thick; did not go white when thick.
>>> My original thought was that I used G200 instead of Custer,
>>> but I did a test and G200 does not make a noticable difference.
>>> I am perfectly willing to do some testing if someone can tell
>>> me what I might have added too much or too little of.
>>> Thanks.
>>>
>>> Steve Burtt
>> > Ocean Springs, Mississippi
>
> __________________________________________________________________________
> ____
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
Lili Krakowski
P.O. Box #1
Constableville, N.Y.
(315) 942-5916/ 397-2389
Be of good courage....
Lili Krakowski on mon 27 dec 04
>I have gleaned the chemical names for Opal Blue Glaze, but haven't a
.clue as to percentages. I haven't found this in the archives.
>Custer Feldspar
>Silica
>Gerstley Borate
>Whiting
>Add Cobalt Carbonate
>Add Rutile
And John asks can we help him define the recipe with quantities of what =
is used....
Well. John, I once ate a lovely cake: It had flour, sugar, butter, =
eggs, and they added vanilla and rum. Can you tell me the amounts.
No, I am not making fun of your request. Many newbies have the same =
approach. So let me explain.
All we know so far is what isn't in your glaze. There is no zinc, no =
lithium, too little magnesium to matter.
You have a lot of calcium and strontium, a decent amount of KNaO and =
boron. You do not have much alumina nor silica.
As you do not tell us what temperature this is at, no one knows --but =
from the absence of silica and or clay as ingredients I guess it is =
pretty low.
Coming in from the other side: strontium was substituted for barium =
some years ago, when the dangers of barium became well known. The =
reason for barium or strontium in glazes is that, with copper, they =
produce a beautiful blue.
But here you are using cobalt, making me think someone substituted =
strontium for barium and then experimented with other colorants.
Small amounts of cobalt and rutile or pure titanium in a boron glaze =
will produce opalescent colors. =20
Having said all this, I would suggest that you seek out a high calcium =
glaze at your temperature, preferably one that contains a frit with =
potash in it. You will want to replace the GB with a frit anyway. =
There are plenty of high calcium borate frits.
So go scour the magazines and books...and good luck.
Lili Krakowski
Be of good cour
John Rodgers on tue 28 dec 04
Lili, I was looking for the percentages for this ^6 glaze, so that I
could mixa batch from 0 to 20,000 grams if I wished. I had some specific
quantities of materials, but they added up to 130% which told me I
didn't have the right information. The numbers are now in my possession
and I am proceeding to make a test batch.
I didn't know about all the other stuff of which you wrote, but it was
very informative.
Thanks,
John Rodgers
Chelsea, AL
Lili Krakowski wrote:
>>I have gleaned the chemical names for Opal Blue Glaze, but haven't a
>>
>>
>.clue as to percentages. I haven't found this in the archives.
>
>
>
>>Custer Feldspar
>>Silica
>>Gerstley Borate
>>Whiting
>>
>>
>
>
>
>>Add Cobalt Carbonate
>>Add Rutile
>>
>>
>
>And John asks can we help him define the recipe with quantities of what is used....
>
>Well. John, I once ate a lovely cake: It had flour, sugar, butter, eggs, and they added vanilla and rum. Can you tell me the amounts.
>
>No, I am not making fun of your request. Many newbies have the same approach. So let me explain.
>
>All we know so far is what isn't in your glaze. There is no zinc, no lithium, too little magnesium to matter.
>
>You have a lot of calcium and strontium, a decent amount of KNaO and boron. You do not have much alumina nor silica.
>
>As you do not tell us what temperature this is at, no one knows --but from the absence of silica and or clay as ingredients I guess it is pretty low.
>
>Coming in from the other side: strontium was substituted for barium some years ago, when the dangers of barium became well known. The reason for barium or strontium in glazes is that, with copper, they produce a beautiful blue.
>
>But here you are using cobalt, making me think someone substituted strontium for barium and then experimented with other colorants.
>
>Small amounts of cobalt and rutile or pure titanium in a boron glaze will produce opalescent colors.
>
>Having said all this, I would suggest that you seek out a high calcium glaze at your temperature, preferably one that contains a frit with potash in it. You will want to replace the GB with a frit anyway. There are plenty of high calcium borate frits.
>
>So go scour the magazines and books...and good luck.
>
>
>
>Lili Krakowski
>
>
>Be of good cour
>
>______________________________________________________________________________
>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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