Craig Martell on mon 21 mar 05
Hello again:
Sorry about the typo in my previous post. It IS actually A-30. I didn't
punch the zero hard enough. So it goes.
I don't mean to butt in to your personal life but I was wondering why you
were wanting A-30 in lieu of anything else. I have some of the stuff that
Lee mentioned too, which is Spectrum A-270. It's very good Neph
sy. Canadian stuff. Is there a possibility that some other type would
work just as well for you? If not, there are a couple of places I could
check. Can't promise anything but you never know.
regards, Craig Martell in Hopewell, Oregon
Edwards on mon 21 mar 05
Hello -- I have been looking for a supplier that carries Unimin's A-30
Nephiline Syenite. So far no luck. Does anybody know of one. Any help
would be greatly appreciated. TIA
~Craig
Craig Martell on mon 21 mar 05
Hi:
The best thing to do sometimes is run an internet search on the product
name and the manufacturer. A search of Unimin Specialty Minerals will
bring up a lot of info.
Hall Technologies for example runs thru the central US from Minnesota to
Texas and they say that they carry some Unimin Neph Sy. They list Minex
but not A-3. But they might be worth a try depending on how much you want.
I get A-3 from Georgie's Ceramic and Clay Co in Portland, Oregon but that
might be too distant a location.
regards, Craig Martell Hopewell, Oregon
Edwards on mon 21 mar 05
Hello Craig and Wayne -- Thanks for the info -- I've gone through
Unimin, (several different contacts) and I couldn't get the name of any
of their A-3 suppliers. They would sell me only in ton lots. A little
more than I need! I'll check into Hall Tech and see what happens. I've
got my spring firing coming up and time is running out on me. So your
input is greatly appreciated.
Cheers,
~Craig.
Craig Martell wrote:
> Hi:
>
> The best thing to do sometimes is run an internet search on the product
> name and the manufacturer. A search of Unimin Specialty Minerals will
> bring up a lot of info.
>
> Hall Technologies for example runs thru the central US from Minnesota to
> Texas and they say that they carry some Unimin Neph Sy. They list Minex
> but not A-3. But they might be worth a try depending on how much you
> want.
>
> I get A-3 from Georgie's Ceramic and Clay Co in Portland, Oregon but that
> might be too distant a location.
>
> regards, Craig Martell Hopewell, Oregon
>
> _
Edwards on tue 22 mar 05
Hello John: It seems as if we are thinking along the same lines. Thanks
for the insight into what you have been doing with shino's. I usually
put the shino's about 15 feet back from the firebox so they can roast at
a medium ^4-6 for a long time. I have a rock crusher and it does
indeed create a different shaped particle. I hadn't thought of using
A-30 along with A-400 but I see that it makes allot of sense. Thanks,
that's a great insight. Your post was as thoughtful and complete as
they always are!
The Best,
~Craig
John Baymore wrote:
>Craig,
>
>Back in 1996 when I was in Japan to receive the award in Mashiko I also
>traveled down to the Seto/Mino area to do a little research on shino. One
>very generous shinoware potter there spent a lot of time with me (in a
>combination of my 1st grade Japanese and his 1st grade English) explaining
>a lot of stuff. I have found that the A-30 is a great ingredient if you
>are looking to replicate a more traditional looking shino glaze too. My
>current shino glaze testing "direction" uses Peak 270 and A-400 Neph Syn,
>plus some A-30.
>
>I was told (and shown) that the "rock" that is the main core ingredient
>(with little else, by the way) of true Japanese shino is a very coarse
>crushing and has a wide particle size distribution from "fines" up to
>almost sand sized. But also of great importance is the fact that the best
>stuff they use comes from a stamper mill...... and it is not water ground
>like US traditional materials. This leaves thin sharp edges to the tiny
>particles... which allows them to sinter along the edges at far lower
>temperatures than their water ground cousins. Japanese shino is typically
>(traditionally) fired to a bit lower end point temperature than most
>western potters fire it but it is fired in very LONG cycles....... for
>lots of heat work.
>
>best,
>
>................john
>
>
>
Craig Martell on tue 22 mar 05
Hello again Craig:
I thought that your search for A-30 was probably a particle size
thing. Your reasons for using A-30 in a long woodfire are sound as a
dollar from my end of the plank.
I used a small amount of A-30 in a body that I fired to cone 2 that was
used to make glass slumping molds. Some of these were fairly large and I
needed some "tooth" in the body but it had to be as low in silica as
possible and smooth. Grog wouldn't work but the A-30 was great. Fluxed
out enough so the surface of the molds were very nice.
The A-30 made me think of another particle size joy ride that I took. I
was making some porcelain bodies with mostly primary kaolins and no ball
clay. I wanted some working strength so I tried a mix of different quartz
sizes for tooth. I used US Silica #90 which is supposed to be 200 mesh but
is really a lot finer, and US Silica #250 which is roughly 60 mesh. The
bodies threw very well and had a nice amount of working strength. There
were crazing problems though due to the larger particle silica not being
fully disolved in the body. I fire to cone 10 R and use a 12 hour firing
from ambient temp to cone 10. Not enough heat work for the chunky
stuff. I thought that these bodies would be good in a longer fire or a
really protracted wood fire with a high end point like cone 12 plus.
Glad to hear that you've scored some A-30.
round and round we go, Craig Martell in Hopewell, Oregon
Edwards on tue 22 mar 05
Hello Craig: Thanks for asking. I'll muddle on through my twisted logic
about needing A-30. The A-30 refers to the grind of the Neph Sy. It is
a Unimin product like the Spectrum A-270. A-270 is a flour a large %
will pass through a 270 mesh sieve. With A-30 , about 50% will pass
through a 30 mesh sieve. It is a coarse sand. I would like to use it for
two things. First as an inclusion in a clay body. At present I use
Custer Feldspar that I get from the mine as silo feed. I crush it up and
add it to the clay. Custer is rather refractory, it works well in the
front of my kiln that gets hot for a long time. Neph Sy has a much lower
deformation temp. So it will be easier to get a Sigaraki effect with it.
Second, to use in Karatsu style shino glazes. It will give me a
larger and more varied particle size, and hopefully a more interesting
glaze. It takes longer to melt, but I fire for 5 days as a rule already.
A-30 is not as processed as A-270, and has a much more varied particle
size distribution. It is my belief that one of the reasons that some of
the ancient oriental glazes are interesting is because of materials that
they use are less refined than we use now.
There it is, it's a starting point. The direction that I'm headed is
what I call neo-gnarly . There are two things that are needed. First
the pots see the full effect of the fire(flame) and second the use of
less refined materials. This is why I'm interested in the A-30 NS and
other unrefined materials.
Well, there you have it Craig, a glimse into my chaotic and distorted
personal life.
Craig Martell wrote:
>
> I don't mean to butt in to your personal life but I was wondering why you
> were wanting A-30 in lieu of anything else. I have some of the stuff
> that
> Lee mentioned too, which is Spectrum A-270. It's very good Neph
> sy. Canadian stuff. Is there a possibility that some other type would
> work just as well for you? If not, there are a couple of places I could
> check. Can't promise anything but you never know.
Edwards on tue 22 mar 05
Hello Craig-- I just hit paydirt-- I called Hall and they didin't
service Minnesota but they gave me the name of the Cary Co. out of
Chicago that did. No problem -- a 50 lb bag -- sample order. Shipped out
today. Thanks so much. I'll post to the list the results!
One happy camper.
~Craig
Craig Martell wrote:
> Hi:
>
> The best thing to do sometimes is run an internet search on the product
> name and the manufacturer. A search of Unimin Specialty Minerals will
> bring up a lot of info.
>
> Hall Technologies for example runs thru the central US from Minnesota to
> Texas and they say that they carry some Unimin Neph Sy. They list Minex
> but not A-3. But they might be worth a try depending on how much you
> want.
>
> regards, Craig Martell Hopewell, Oregon
>
John Baymore on tue 22 mar 05
Craig,
Back in 1996 when I was in Japan to receive the award in Mashiko I also
traveled down to the Seto/Mino area to do a little research on shino. One
very generous shinoware potter there spent a lot of time with me (in a
combination of my 1st grade Japanese and his 1st grade English) explaining
a lot of stuff. I have found that the A-30 is a great ingredient if you
are looking to replicate a more traditional looking shino glaze too. My
current shino glaze testing "direction" uses Peak 270 and A-400 Neph Syn,
plus some A-30.
I was told (and shown) that the "rock" that is the main core ingredient
(with little else, by the way) of true Japanese shino is a very coarse
crushing and has a wide particle size distribution from "fines" up to
almost sand sized. But also of great importance is the fact that the best
stuff they use comes from a stamper mill...... and it is not water ground
like US traditional materials. This leaves thin sharp edges to the tiny
particles... which allows them to sinter along the edges at far lower
temperatures than their water ground cousins. Japanese shino is typically
(traditionally) fired to a bit lower end point temperature than most
western potters fire it but it is fired in very LONG cycles....... for
lots of heat work.
best,
................john
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
JBaymore@compuserve.com
http://www.JohnBaymore.com
Lee Love on tue 22 mar 05
Edwards wrote:
> Hello -- I have been looking for a supplier that carries Unimin's A-30
> Nephiline Syenite. So far no luck. Does anybody know of one. Any help
> would be greatly appreciated. TIA
Hi Craig,
I have a bag of it. (would have looked sooner, but didn't
think I could have it here in Japan.) The title on the bag is Spectrum
A-270 They sell it at Trinity:
http://www.trinityceramic.com/Feldspars.htm
Or You might contact Unimin direct:
*Unimin Corp.*
258 Elm St.
New Canaan, CT 06840
Phone: 203-966-8880|
Fax: 203-966-3453
Web URL: http://www.unimin.com/
Produce and market silica sands, ground and microcrystalline silica,
feldspar, and nepheline syenite for the glass, whitewares, enamel, and
ceramic powder industries. Operations throughout North America with
technical service and worldwide distribution. Toll free: 800-243-9004,
fax: 800-243-9005. Unimin Canada Ltd., 5343 Dundas St.,W., Ste. 400,
Etobicoke, ON M9B 6K5; 416-232-2003, fax: 416-232-2389.
--
Lee in Mashiko, Japan http://mashiko.org
http://potters.blogspot.com/ WEB LOG
http://claycraft.blogspot.com/ Photos!
David Beumee on wed 23 mar 05
Craig wrote,
" There were crazing problems though due to the larger particle silica not being
fully disolved in the body."
My object in formulating clay bodies is always to have them fit a wide range of low to high expansion glazes, so no matter what glaze you might use, the body and glaze will fit. Wouldn't high expansion silica that is not carried into the melt be an opportunity to use less silica, therefore giving you the opportunity to use increased percentages of clay, thereby increasing workability?
David Beumee
www.davidbeumee.com
Lafayette, CO
-------------- Original message ----------------------
From: Craig Martell
> Hello again Craig:
>
> I thought that your search for A-30 was probably a particle size
> thing. Your reasons for using A-30 in a long woodfire are sound as a
> dollar from my end of the plank.
>
> I used a small amount of A-30 in a body that I fired to cone 2 that was
> used to make glass slumping molds. Some of these were fairly large and I
> needed some "tooth" in the body but it had to be as low in silica as
> possible and smooth. Grog wouldn't work but the A-30 was great. Fluxed
> out enough so the surface of the molds were very nice.
>
> The A-30 made me think of another particle size joy ride that I took. I
> was making some porcelain bodies with mostly primary kaolins and no ball
> clay. I wanted some working strength so I tried a mix of different quartz
> sizes for tooth. I used US Silica #90 which is supposed to be 200 mesh but
> is really a lot finer, and US Silica #250 which is roughly 60 mesh. The
> bodies threw very well and had a nice amount of working strength. There
> were crazing problems though due to the larger particle silica not being
> fully disolved in the body. I fire to cone 10 R and use a 12 hour firing
> from ambient temp to cone 10. Not enough heat work for the chunky
> stuff. I thought that these bodies would be good in a longer fire or a
> really protracted wood fire with a high end point like cone 12 plus.
>
> Glad to hear that you've scored some A-30.
>
> round and round we go, Craig Martell in Hopewell, Oregon
>
> ______________________________________________________________________________
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Craig Martell on wed 23 mar 05
>Wouldn't high expansion silica that is not carried into the melt be an
>opportunity to use less silica, therefore giving you the opportunity to
>use increased percentages of clay, thereby increasing workability?
Hello David:
Not in my experience but as usual, it depends. The body composition, in
total, is what determines everything.
Feldspar is considered the "high expansion" element in porcelain and
porcelaineous bodies. There needs to be a sufficient amount of quartz to
facilitate the "quartz hump" at 1032F and this is dependent on the amount
of feldspar needed to fuse the body to one's liking. This is what puts
most balanced glazes into compressive fit. If X amount of quartz is needed
in the fused state and a certain amount is not fused due to larger particle
sizing there will be a lessening of the amount of expansion/contraction at
the quartz inversion point. Fused silica has a lower expansion coefficient
than crystalline silica, (this is the "it depends" part). Ergo, if the
larger particle quartz isn't fully fused and assimilated into the body
glass it well remain in the crystalline state and cause glaze fit
problems. My tests have proved this beyond any resonable doubt. But these
are my interpretations and, as always, are welcome to all levels of skepticism.
FYI, the silica blend that I used which produced good workability and
almost fit my glazes was: 18% US Silica #90 and 7% US Silica # 250. I
used higher blends of #250 and the higher I went the farther off went the
glaze fit. Your milage may vary.
regards, Craig Martell Hopewell, Oregon
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