Chris Schafale on sun 8 jan 06
Steve,
One other idea comes to mind, and you may have already looked at this, but
is it possible that your glazes were also mixed a tad too thin? I say that
because the symptoms you describe could, in my experience, also be caused
by a glaze coat that is too thin. My cobalt green glaze, for instance, is
only green if I apply it quite thin, and becomes blue where it's
thick. Interesting brown glazes, too, often require a thick enough coat to
develop their variability.
Chris
>Steve burtt wrote:
> Hi all,
>
> A few of my glazes are from "Mastering Cone 6 Glazes," and they have
> changed. My waterfall brown, for instance, is almost black. I had a
> sapphire blue glaze that has become a flat green.
Tom at Hutchtel.net on mon 9 jan 06
Please do go back into the archives on this one....3, maybe 5 years. It was
heavily covered. Not only do the various rutiles vary considerably, the
same rutile will vary in its effect on your glaze by mesh. Generally your
suppliers do not really know what they're selling when it comes to
rutile...some do but most don't.
And to the suggestion about subbing Titanium Diox (add a little iron too),
Tom Buck once developed a glaze doing exactly that. It actually was a
better glaze than the original.
We had this problem back then and did exactly what Mr. Hesselberth
suggested. Finally found the one that worked at a supplier we rarely bought
from...then we got the 50 lb bag. The analysis MAY not give you the
answer....test, test, test.
Tom Wirt
Hutchinson, MN
twirt@hutchtel.net
www.claycoyote.com
> It makes me think about how Ron and John are always recommending one
> obtains analyses for the raw materials. If you had an old one and a new
> one, you'd be able to figure out what the difference is and make
> adjustments accordingly.
>
> Pe
Steve burtt on mon 9 jan 06
Hi all,
I have had a problem with my glaze chemicals, specifically rutile. My source has confirmed that rutile has changed. They don't know why, but it has. And it has affected several of my glazes in our community pottery program here in Ocean Springs. A few of my glazes are from "Mastering Cone 6 Glazes," and they have changed. My waterfall brown, for instance, is almost black. I had a sapphire blue glaze that has become a flat green.
I've done some tests reducing the amount of rutile, but that does not seem to work. Any other suggestions about what direction I should take? Thanks so much.
Steve Burtt
Ocean Springs, Mississippi
---------------------------------
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John Hesselberth on mon 9 jan 06
Hi Steve,
First thing I would do is buy small amounts of the different grades
available. Your supplier may only have one, but there are several
available including a ceramic grade and 'dark'. Ask each supplier for
the full lot and type numbers off the large bag she buys. Someplace
in the archives, maybe 5 years ago, Richard Aerni had a lengthy post
about rutile grades. Once you find one that works, buy a 10 year supply.
Regards,
John
On Jan 9, 2006, at 1:28 PM, Steve burtt wrote:
> Hi all,
>
> I have had a problem with my glaze chemicals, specifically
> rutile. My source has confirmed that rutile has changed. They don't
> know why, but it has. And it has affected several of my glazes in
> our community pottery program here in Ocean Springs. A few of my
> glazes are from "Mastering Cone 6 Glazes," and they have changed.
> My waterfall brown, for instance, is almost black. I had a sapphire
> blue glaze that has become a flat green.
>
Randall Moody on mon 9 jan 06
You could ask them how the rutile has changed. Specifically the chemical
make up. That could point you in a direction to change the recipe. If they
don't know you could ask for a contact person at their supplier.
On 1/9/06, Steve burtt wrote:
>
> Hi all,
>
> I have had a problem with my glaze chemicals, specifically rutile.
> My source has confirmed that rutile has changed. They don't know why, but=
it
> has.
>
Chris Schafale on mon 9 jan 06
How about making a batch using pure titanium oxide instead of rutile, and
then line blend with the bad batch to see if you get the old look somewhere
in the middle?
Chris
At 01:28 PM 01/09/2006, you wrote:
>Hi all,
>
> I have had a problem with my glaze chemicals, specifically rutile.
> My source has confirmed that rutile has changed. They don't know why, but
> it has. And it has affected several of my glazes in our community pottery
> program here in Ocean Springs. A few of my glazes are from "Mastering
> Cone 6 Glazes," and they have changed. My waterfall brown, for instance,
> is almost black. I had a sapphire blue glaze that has become a flat green.
> I've done some tests reducing the amount of rutile, but that does
> not seem to work. Any other suggestions about what direction I should
> take? Thanks so much.
>
> Steve Burtt
> Ocean Springs, Mississippi
>
>
>
>---------------------------------
> Yahoo! DSL Something to write home about. Just $16.99/mo. or less
>
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Linda Ferzoco on mon 9 jan 06
It makes me think about how Ron and John are always recommending one obtains analyses for the raw materials. If you had an old one and a new one, you'd be able to figure out what the difference is and make adjustments accordingly.
Perhaps it's not too late. Ask the distributor for an analysis and then some folks with glaze calculation software can help you out.
Good luck,
Linda
Pacifica, California
Steve burtt wrote: Hi all,
I have had a problem with my glaze chemicals, specifically rutile.
David Hewitt on wed 11 jan 06
If you were to get your supplies from Bath Potters Supplies you would be
able to look up the analysis on their web site.
More suppliers do give this information these days, but they may need to
be pressed to give it. As a group I would like to think that we each
press our suppliers for this to be readily available. With the Internet
and the ease with which suppliers can run a web site this should not
make too much of an extra burden on their administration.
Clayarters get going!
David
In message , Linda Ferzoco writes
>It makes me think about how Ron and John are always recommending one
>obtains analyses for the raw materials. If you had an old one and a
>new one, you'd be able to figure out what the difference is and make
>adjustments accordingly.
>
> Perhaps it's not too late. Ask the distributor for an analysis and
>then some folks with glaze calculation software can help you out.
>
> Good luck,
> Linda
> Pacifica, California
>
>Steve burtt wrote: Hi all,
>
> I have had a problem with my glaze chemicals, specifically rutile.
--
David Hewitt
Web:- http://www.dhpot.demon.co.uk
Steve Slatin on wed 11 jan 06
Steve --
This is just a tinkerer's idea, so take that into account ... other folks are
giving you excellent ideas about how to avoid this problem in the future,
and it'd certainly be better to do things their way and get things consistent,
etc. but you've got a pile of rutile now and problems with otherwise
working glazes.
Interestingly, both of the problems you have MIGHT be caused by the
same thing -- too much iron in the glaze. Rutile consists of titanium and
iron, and the psercentages can vary quite a bit. (Up to 15% iron and it's
called rutile; 16 to about 50% iron and it's called ilmenite, IIRC.) Less
commonly found ingredients in what's sold as 'rutile' include tin and chrome
... tin in ox makes things white, not what's going on in your glazes, chrome
makes things green, generally, (Cr+3), though +6 is red-orange. I don't
know what +2 looks like, but in any event it doesn't seem like chrome
is the problem.
So it's likely that you got a bag of rutile with way too much iron.
One easy thing to do would be to check your recipe and if there's any iron
in there, do a quick line blend going from no iron to the standard amount
of iron using the new rutile. If you get the colors you want somewhere in
that range, you're back in business.
If you see color change but not as far as you like, or if there's no iron to
take out of the glaze, make a small batch of the glaze with titanium instead
of rutile (granularity is an issue, as are those other trace ingredients), and do
a line blend with the 'bad' batch. You might not get the same effect with this
combination as with good rutile, but you might get lucky.
Best wishes -- Steve Slatin
Steve burtt wrote:
Hi all,
I have had a problem with my glaze chemicals, specifically rutile. My source has confirmed that rutile has changed. They don't know why, but it has. And it has affected several of my glazes in our community pottery program here in Ocean Springs. A few of my glazes are from "Mastering Cone 6 Glazes," and they have changed. My waterfall brown, for instance, is almost black. I had a sapphire blue glaze that has become a flat green.
I've done some tests reducing the amount of rutile, but that does not seem to work. Any other suggestions about what direction I should take? Thanks so much.
Steve Slatin --
And I've seen it all, I've seen it all
Through the yellow windows of the evening train...
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Richard Aerni on wed 11 jan 06
Steve Slatin gives excellent advice on what may be causing the problem and
how to go about possibly fixing it. I'm not going to go on in any detail
about this, as there are so many possible reasons why the rutile may not be
doing what you want it to, that dispensing fool-proof advice from a distance
would be tough.
Line blending is a good and easy way to go to try to fix the problems. One
caveat...when I had problems with rutile some time ago, I tried all the
obvious line blends (gurus always say just take titania and iron in line
blends and you'll be fine), and none of them "fixed" my problems. Of
course, my problems were of a nature that I think it was the impurities that
I wanted, but that's another thing entirely.
If you are going to look for different sources of rutile, make sure you
familiarize yourself with which suppliers carry what kind of rutile. A lot
of them don't know, and it's just possible that many of them are getting it
from the same source. My supplier, for instance, when I first called and
asked where they got their rutile from, could only say "It came off the
truck from Los Angeles." Find out who supplies the suppliers. Rutile comes
from a number of different places, and is processed in different ways. It
helps to know a bit of mineralogy, and to be persistant in asking questions.
For instance, I found by talking to an engineer at one of the processing
companies in my neck of the woods that Dark Rutile (or Ruflux 61) and
Ceramic Rutile (light) are essentially the same thing. The Ceramic Rutile
is Dark Rutile that has been calcined at low temperature (not exceeding 1000
degrees C, according to my source) in order to burn out "impurities" (I
think he was talking about things like mouse turds and such.) It shouldn't
make any difference to a glaze, but nevertheless I get slightly better
results with the Ceramic Grade Rutile. Many rutiles are blends of materials
from different sources. The one I use is a blend of Australian and Florida
rutiles. I had them hold a pallet from which I got a test sample, and when
my tests worked out OK, then I ordered several hundred pounds from that
pallet. It can change properties from pallet to pallet or batch to batch
(at least for our purposes...probably doesn't make any difference to the
welding rod industry). I've got a whole fistful of chemical analyses...they
all say the same thing, even though the rutiles look completely different
and have different effects on the glazes (at least my glazes), so I don't
really pay any attention to them anymore.
I think you've got to think your way, and test your way out of it. Sorry to
say that, but if anyone thinks they know the answer to your problem from a
distance, I'd be wondering about what they really know. The folks with
experience will tell you what it may be, and things you can do and try to
see if it makes a difference, but the most definitive answer will come from
you and your testing.
Best wishes,
Richard Aerni
Rochester, NY
On Wed, 11 Jan 2006 18:16:43 -0800, Steve Slatin wrote:
>Steve --
>
> This is just a tinkerer's idea, so take that into account ... other folks are
> giving you excellent ideas about how to avoid this problem in the future,
> and it'd certainly be better to do things their way and get things
consistent,
> etc. but you've got a pile of rutile now and problems with otherwise
> working glazes.
>
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