Cindy on fri 3 apr 98
I went to Pacer Corp. (Custer feldspar) the other day to get some spar, and
they gave me a bag of 100 mesh mica to experiment with. I know it can be
used as a grog to give a nice, sparkly clay body, but I don't mix my own
clay. Aside from sprinkling it on wet clay, does anyone have ideas as to
what I can use this for? I'm going to try sprinkling on the surface of wet
glaze, too, but I'm wondering what it would do if mixed into the glaze
itself. I plan to find this out for myself, of course, but in the mean
time, there's non point re-inventing the wheel. If anyone else has played
with this, I'd appreciate hearing from you. Pacer would appreciate it, too,
as they have lots and lots of ground mica and wouldn't mind finding a
market for it.
Thanks,
Cindy Strnad
Earthen Vessels
Custer, SD
USA http://blackhills-info.com/a/cindys/menu.htm
Carrie Wood on sat 4 apr 98
I too have gotten mica from Pacer. I mixed mine up in a Cone 10 body and
fired it. It was fine for throwing and handbuilding. I haven't done a
whole lot of experimenting, but it seems to burn out in the higher temps,
i.e. it was there in my cone 04 bisque-but it was gone from the body after
the high fire. You would do well to speak with Mr. Ziemet (for the life
of me I can't remember his first name) -he's one of Pacer's chemists. I
found him to be extremely knowledgable and helpful. In any case, I hadn't
thought about putting it in a glaze myself-be sure to post your findings
for us.
On Fri, 3 Apr 1998, Cindy wrote:
> ----------------------------Original message----------------------------
> I went to Pacer Corp. (Custer feldspar) the other day to get some spar, and
> they gave me a bag of 100 mesh mica to experiment with. I know it can be
> used as a grog to give a nice, sparkly clay body, but I don't mix my own
> clay. Aside from sprinkling it on wet clay, does anyone have ideas as to
> what I can use this for? I'm going to try sprinkling on the surface of wet
> glaze, too, but I'm wondering what it would do if mixed into the glaze
> itself. I plan to find this out for myself, of course, but in the mean
> time, there's non point re-inventing the wheel. If anyone else has played
> with this, I'd appreciate hearing from you. Pacer would appreciate it, too,
> as they have lots and lots of ground mica and wouldn't mind finding a
> market for it.
>
> Thanks,
>
> Cindy Strnad
> Earthen Vessels
> Custer, SD
> USA http://blackhills-info.com/a/cindys/menu.htm
>
Tyler Hannigan on tue 7 apr 98
Mica being a natural ingredient in much of local clay here in Northern New Mexic
it is utilized by the Tewa Indians and attracted my curiosity. I've used a
commercial clay containing mica and have also added mica flakes to a porcelain
body. I've found it retains its integrity up to cone 6.
Anyone who mixes different colored clays together may find using the same clay
with and without mica has a pleasant, mildly sparkling marble effect.
Good Luck adding this to your resources.
Tyler Hannigan
silverhawk@silverhawk.com
http://www.silverhawk.com/tssa/cm/thann/
Carrie Wood wrote:
> ----------------------------Original message----------------------------
> I too have gotten mica from Pacer. I mixed mine up in a Cone 10 body and
> fired it. It was fine for throwing and handbuilding. I haven't done a
> whole lot of experimenting, but it seems to burn out in the higher temps,
> i.e. it was there in my cone 04 bisque-but it was gone from the body after
> the high fire. You would do well to speak with Mr. Ziemet (for the life
> of me I can't remember his first name) -he's one of Pacer's chemists. I
> found him to be extremely knowledgable and helpful. In any case, I hadn't
> thought about putting it in a glaze myself-be sure to post your findings
> for us.
>
> On Fri, 3 Apr 1998, Cindy wrote:
>
> > ----------------------------Original message----------------------------
> > I went to Pacer Corp. (Custer feldspar) the other day to get some spar, and
> > they gave me a bag of 100 mesh mica to experiment with. I know it can be
> > used as a grog to give a nice, sparkly clay body, but I don't mix my own
> > clay. Aside from sprinkling it on wet clay, does anyone have ideas as to
> > what I can use this for? I'm going to try sprinkling on the surface of wet
> > glaze, too, but I'm wondering what it would do if mixed into the glaze
> > itself. I plan to find this out for myself, of course, but in the mean
> > time, there's non point re-inventing the wheel. If anyone else has played
> > with this, I'd appreciate hearing from you. Pacer would appreciate it, too,
> > as they have lots and lots of ground mica and wouldn't mind finding a
> > market for it.
> >
> > Thanks,
> >
> > Cindy Strnad
> > Earthen Vessels
> > Custer, SD
> > USA http://blackhills-info.com/a/cindys/menu.htm
> >
Jack Ward on sat 18 apr 98
Look up mica in "Pioneer Pottery by Michaael Cardew.
> ----------------------------Original
> message----------------------------
> I went to Pacer Corp. (Custer feldspar) the other day to get some
> spar, and
> they gave me a bag of 100 mesh mica to experiment with. I know it can
> be
> used as a grog to give a nice, sparkly clay body, but I don't mix my
> own
> clay. Aside from sprinkling it on wet clay, does anyone have ideas as
> to
> what I can use this for? I'm going to try sprinkling on the surface of
> wet
> glaze, too, but I'm wondering what it would do if mixed into the glaze
>
> itself. I plan to find this out for myself, of course, but in the mean
>
> time, there's non point re-inventing the wheel. If anyone else has
> played
> with this, I'd appreciate hearing from you. Pacer would appreciate it,
> too,
> as they have lots and lots of ground mica and wouldn't mind finding a
> market for it.
>
> Thanks,
>
> Cindy Strnad
> Earthen Vessels
> Custer, SD
> USA http://blackhills-info.com/a/cindys/menu.htm
Jeffrey James on tue 11 aug 98
Help I am looking for a supplier for Mica to be added to clay if anyone
knows of a supplier please post it.
Think You
Jeff
Don MacDonald on wed 12 aug 98
Laguna Clay Company, City of Industry, Calif. carries 325 mesh mica.
Jeffrey James wrote:
>
> ----------------------------Original message----------------------------
> Help I am looking for a supplier for Mica to be added to clay if anyone
> knows of a supplier please post it.
> Think You
> Jeff
Tyler Hannigan on wed 12 aug 98
MICA!
My local supplier has it,,,,,,,,,, but no email;
Tierra Hermossa Pottery & Ceramic Supply
316 Paseo Del Pueblo Sur
PO Box 5002
Taos, NM 87571
(505) 751-0458
--
Tyler Hannigan
Silverhawk Craft Realm
http://www.silverhawk.com/ex98
FRANK GAYDOS on wed 12 aug 98
Jeffrey James wrote:
>
> ----------------------------Original message----------------------------
> Help I am looking for a supplier for Mica to be added to clay if anyone
> knows of a supplier please post it.
> Think You
> Jeff
Jeff,
Pacer Corp. is a great source. You can find them at:
http://www.ceramics.com/pacer/
Hope this helps
--
Frank Gaydos
510 Gerritt St.
Philadelphia,Pa.19147-5821 USA
fgaydos@erols.com
Jeff Lawrence on wed 12 aug 98
Jeffrey James wrote:
>Help I am looking for a supplier for Mica to be added to clay if anyone
>knows of a supplier please post it.
>
Jeff, try Ceramic King, Alb. NM, 800-781-CLAY
Jeff Lawrence
jml@sundagger.com
Sun Dagger Design
Rt 3 Box 220
Espanola, NM 87532
ph 505-753-5913
mel jacobson on wed 28 jun 00
one of our campers is interested in what temp mica will
melt.
and, can it be used in ceramics.
the gas/electric kiln is on and is almost at 1500.
we will give you the news tomorrow.
mel
http://www.pclink.com/melpots
written from the farm in wisconsin
ENJB@AOL.COM on wed 28 jun 00
Mica was one of the local ingredients in chinese porcelains. I've used in a
porcelain body. If I remember correctly, Highwater has mica in their white
low fire body.
nanci
Pamala Browne on thu 29 jun 00
Micaceous (sp?) clay was used by the Pueblo Indians -- gorgeous orange pots
with sparkles. So, yes it can be used ,but I do not know it's melting
temp -- I'd stay with low-fire.
You know , I've seen it sold in bags . A woman in Taos sold it from
her shop, can't remember the name of it right now, but I can find it if you
need it Hope this helps pamalab
----- Original Message -----
From: mel jacobson
To:
Sent: Wednesday, June 28, 2000 11:41 AM
Subject: mica
> one of our campers is interested in what temp mica will
> melt.
> and, can it be used in ceramics.
>
> the gas/electric kiln is on and is almost at 1500.
> we will give you the news tomorrow.
>
> mel
> http://www.pclink.com/melpots
> written from the farm in wisconsin
>
>
____________________________________________________________________________
__
> 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.
>
David Clark on fri 30 jun 00
Hey how's Palmdale (did I remember that right?)
Any way I just read your e-mail on Mica. I too am interested in it.
Especially since I've read and visited the Taos reservation. The pieces are
beautiful if you like just the clay without slip decoration. With some
exceptions.
I'd be interested in knowing where I might find some Mica in the raw. I
thought I might add it to Raku, if not cost prohibitive. My understanding is
that it adds great thermal shock resistance.
Thanks, Dave C. in Upland
>From: Pamala Browne
>Reply-To: Ceramic Arts Discussion List
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Re: mica
>Date: Thu, 29 Jun 2000 11:17:57 -0700
>
>Micaceous (sp?) clay was used by the Pueblo Indians -- gorgeous orange pots
>with sparkles. So, yes it can be used ,but I do not know it's melting
>temp -- I'd stay with low-fire.
> You know , I've seen it sold in bags . A woman in Taos sold it from
>her shop, can't remember the name of it right now, but I can find it if you
>need it Hope this helps pamalab
>
>
>
>----- Original Message -----
>From: mel jacobson
>To:
>Sent: Wednesday, June 28, 2000 11:41 AM
>Subject: mica
>
>
> > one of our campers is interested in what temp mica will
> > melt.
> > and, can it be used in ceramics.
> >
> > the gas/electric kiln is on and is almost at 1500.
> > we will give you the news tomorrow.
> >
> > mel
> > http://www.pclink.com/melpots
> > written from the farm in wisconsin
> >
> >
>____________________________________________________________________________
>__
> > 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.
> >
>
>______________________________________________________________________________
>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.
________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com
Cindy Strnad on sat 1 jul 00
David, Mel, and others;
If you want mica, or information about mica, contact the Pacer Corporation
at 35 S 6th St, Custer, SD 57730, (605)673-4419. Mica melts at around ^5, I
think, but I can't remember the exact temperature. Pacer has a data sheet
for it. It'll give you silica and other stuff for your glaze, but no pretty,
sparkly, shimmery look unless you fire it low enough. It's lovely in
pit-fired work.
I'm sure Pacer isn't interested in selling mica to individual potters from
their corporate offices here in Custer, but they *are* interested in
developing markets for it and would be interested (or so they told me a year
ago) in working with people who would experiment and possibly find new uses
for this byproduct of producing Custer feldspar.
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
earthenv@gwtc.net
Sheron Roberts on sat 1 jul 00
At a workshop at John Campbell
Folk School we played around with
mica a little. After applying
terra sigilatta to our pots we
sprinkled mica on the insides and
fired to cone 06 (the pots were
white earthenware). The mica
turned to "fairy dust", pretty
golden dust. It didn't stick to=20
the terra sig though and most
would have come off if not inside
the bowl. I have since then wanted
to experiment with mica more.
I don't know where the instructor
found her mica, but I have seen
it in rock shops.
Sheron in NC
Oooladies@AOL.COM on sun 2 jul 00
speaking of mica.... doesn't it also come in sheets? Or am I thinking of
something different? What I am thinking of as mica is a shale type of rock
that you can break off layers of clear layers. My thought would be to try to
use some of the layered mica as a 'window' in a piece. has anyone ever tried
anything with the 'sheet type mica?
marie gibbons
Lori Wilkinson on sun 2 jul 00
Marie, We had a pot bellied stove and used Mica sheets in the windows. In
time they turned yellowish don't know if it was from the heat or wood fumes.
Wasn't it called "isinglass"? One thing I do remember is back in the 70s is
it was extremely hard to come by.
Lori Wilkinson
Tim & Lori Wilkinson
DOWN TO EARTH POTTERY
Roswell, New Mexico
http://www.geocities.com/SoHo/Gallery/1165/
-----Original Message-----
From: Oooladies@AOL.COM
To: CLAYART@LSV.CERAMICS.ORG
Date: Sunday, July 02, 2000 6:10 AM
Subject: Re: mica
>speaking of mica.... doesn't it also come in sheets? Or am I thinking of
>something different? What I am thinking of as mica is a shale type of rock
>that you can break off layers of clear layers. My thought would be to try
to
>use some of the layered mica as a 'window' in a piece. has anyone ever
tried
>anything with the 'sheet type mica?
>marie gibbons
>
>___________________________________________________________________________
___
>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.
>
CNW on sun 2 jul 00
Mica also comes in the form of "expanded mica" commonly known as
"vermiculite". It can be mixed with your clay or glaze in that form or you
can mash it up.
oops-you get it at the garden supply or home supply - I think they use it
for insulation some times but that is coarse. You can get it in different
levels of coarse/fine but you have to ask around.
Sheron that sparkly stuff floating in the creek when you wade around here is
mica. Hunt around and you will find it. It is gray-transparent and in flat
layers (crystals) and sometimes in gold looking layers.
Celia in NC
cwike@conninc.com
David Clark on sun 2 jul 00
Actually you are right. Up in Sky City aka Acoma Indian reservation in New
Mexico there is an Adobe house whose window is actually a large piece of
Mica set in the wall and used to allow some light in. It's very impressive
as it is about an inch thick and just under a foot square.
Dave Clark, Upland, Cal.
>From: Oooladies@AOL.COM
>Reply-To: Ceramic Arts Discussion List
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Re: mica
>Date: Sun, 2 Jul 2000 00:59:14 EDT
>
>speaking of mica.... doesn't it also come in sheets? Or am I thinking of
>something different? What I am thinking of as mica is a shale type of rock
>that you can break off layers of clear layers. My thought would be to try
>to
>use some of the layered mica as a 'window' in a piece. has anyone ever
>tried
>anything with the 'sheet type mica?
>marie gibbons
>
>______________________________________________________________________________
>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.
________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com
Tim J Havens on sun 2 jul 00
Your looking for " Isinglass " or sheet mica . It can be found in a
synthetic form ; not sure where these days . It is also formable to a
small extent so it can take curves . The stuff does not mind the heat so
much as plastic so it is good for lamps . I've lost my contact for the
stuff so if you find a source would you post it for me please.
Alohaz Tim.
________________________________________________________________
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Larry Phillips on sun 2 jul 00
Oooladies@AOL.COM wrote:
>
> speaking of mica.... doesn't it also come in sheets?
It sure does.
> What I am thinking of as mica is a shale type of rock that you can
> break off layers of clear layers. My thought would be to try to use
> some of the layered mica as a 'window' in a piece. has anyone ever
> tried anything with the 'sheet type mica?
No, but what a neat idea. Anyone have any idea where one might look for
a source of it?
--
Hukt on fonix werkt fer me!
http://cr347197-a.surrey1.bc.wave.home.com/larry/
Oooladies@AOL.COM on sun 2 jul 00
Thanks to all who replied about the mica ....
I am gonna experiment here with some. I have one small but kinda thick
piece, so i will see if I can split it into layers to use as built in
windows, and see what it does in a firing. Boy I wish I still lived in the
house I grew up in, we had a big ole rock full of the stuff, musta been at
least 3 foot wide and 7 foot long! we used to pry up sheets of it and make
windows in cardboard appliance boxes!!
I will keep you all posted on my experiment! I am also gonna try visiting
some local rock shops and see what they know about finding the stuff!
thanks again,
marie gibbons
www.oooladies.com
Ron Collins on thu 11 jan 01
I am firing the test kiln now, trying some things, but would like to put =
the question out, and hopefully someone may help me out, as I have never =
been a glazemeister...of what use, if any, is mica as a glaze material? =
I know of, but have never seen, micaceous clay pottery, but does it =
have any other uses? Ron knows where a mountain of it is, free for the =
taking by the side of the dirt road, in the mountains of Guatemala, and =
he says at 8 am it looks like a mountain of gold....has anyone used it =
for anything, ceramic/wise, except as a clay addition? Melinda
Ron Collins on fri 12 jan 01
Lowell, I was told also that it could have fluxing potential so will
see...unfortunately, it requires 4WD and my little pickup can't go and we
will have to wait until Ron goes "jade mining" again to get some quantity of
it. It's sheet mica-up to 2 inches..got some interesting effects last
night...with the golden sand it's in, fired, it looks like little mounds of
gold in a white glaze...only if it's sprinkled on top not in...it's a
novelty for me,just playing around, I don't think much will come of it
really...unless, like I was told, it makes pots so strong thermally, that
they can just be fired in a campfire, fireplace situation....don't know
anything much about micaceous clay, but it sounds interesting and when I
looked it up on the net, it sure seems to go for a lot of money...they are
proud of their micaceous clay in NM! Melinda
Ron Collins on fri 12 jan 01
Snail-I've made stovetop beanpots and rice cookers here out of the local
earthenware just for fun when I first came and use them to cook on top of
the gas stove....but if mica can really make that much of a difference, what
fun firing could be for the students-and me-and have them glitter like
gold...the 1/4" and down mica flakes I sprinkled on top of a white 06 gl.
combined with the golden sand they were in, made beautiful little mounds of
gold...well, maybe looks like pyrite, but pretty and just a novelty, I
guess, until I get enough of it to make some micaceous clay, and according
to the prices of the pots made from it I looked at on the net, I'll really
have a "gold" mine....thanks for the input and I'm going to see what happens
with the micaceous clay and fire them in the fireplace ....Melinda
Marcia Selsor on fri 12 jan 01
Dear Ron,
I had experimented with vermiculite in Raku clay bodies 30 years ago.
(Now it is claimed to contain asbestos). I also had some very fine mica
given to me by the Geology Prof. I pressed it into surfaces of raku. I
thought the contrast with the black body could be interesting.
Unfortunately I reminded me of Elvis painting on Black Velvet. BUT it
can be used. I never fired it to high temps. so I don't know what it can do.
Best wishes,
Marcia
Ron Collins wrote:
>
> I am firing the test kiln now, trying some things, but would like to put the question out, and hopefully someone may help me out, as I have never been a glazemeister...of what use, if any, is mica as a glaze material? I know of, but have never seen, micaceous clay pottery, but does it have any other uses? Ron knows where a mountain of it is, free for the taking by the side of the dirt road, in the mountains of Guatemala, and he says at 8 am it looks like a mountain of gold....has anyone used it for anything, ceramic/wise, except as a clay addition? Melinda
>
> ______________________________________________________________________________
> 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.
--
Marcia Selsor
selsor@imt.net
http://www.imt.net/~mjbmls
http://www.imt.net/~mjbmls/Tuscany2001.html
Snail Scott on fri 12 jan 01
At 07:50 PM 1/11/01 -0600, you wrote:
>I am firing the test kiln now, trying some things, but would like to put
the question out, and hopefully someone may help me out, as I have never
been a glazemeister...of what use, if any, is mica as a glaze material? I
know of, but have never seen, micaceous clay pottery, but does it have any
other uses? Ron knows where a mountain of it is, free for the taking by
the side of the dirt road, in the mountains of Guatemala, and he says at 8
am it looks like a mountain of gold....has anyone used it for anything,
ceramic/wise, except as a clay addition? Melinda
Mica is terrific for fighting thermal shock. I have seen
Jicarilla Apache micaceous pots fired on an open fire;
no kiln, no saggar, not even the shards or license plates
that Acoma potters need. I've seen Acoma pots shatter when
a shard slips off or an errant breeze hits the firing at
a bad angle. Those Jicarilla pots fire right out there in
the open wind, no problem! (They are used for stovetop ware.)
Mica platelets also make the bare clay look sparkly, and it
can be added to slips to cover plain clay. If you want the
thermal-shock resistance without the sparkle, grind it to a
powder before adding to the clay.
The chemical formula of light-colored mica is K2O.3Al2O3.6SiO2.2H2O
It is a mild flux, but not widely used as such in glazes,
to my knowledge.
-Snail
Frank Gaydos on fri 12 jan 01
Melinda,
I have used it in glazes with mixed results. I think it depends on the
glaze.
There should be lots of info in the archives.
Frank Gaydos
----- Original Message -----
Subject: mica
I am firing the test kiln now, trying some things, but would like to put the
question out, and hopefully someone may help me out, as I have never been a
glazemeister...of what use, if any, is mica as a glaze material? I know of,
but have never seen, micaceous clay pottery, but does it have any other
uses? Ron knows where a mountain of it is, free for the taking by the side
of the dirt road, in the mountains of Guatemala, and he says at 8 am it
looks like a mountain of gold....has anyone used it for anything,
ceramic/wise, except as a clay addition? Melinda
LOWELL BAKER on fri 12 jan 01
Melinda:
Sounds like Ron has been a busy boy. You are certainly living in a
very interesting geological region and have a world of materials at
hand. One thing I would be curious about in your Mica is; is it
sheet Mica or something called Flogpite Mica which is a much
smaller structure that is formed in the volcanic rock/ash as it cools
and then weathers out and is collected in the sedimentary
deposits? Pick up one of those small round boulders in the small
aroyas near you and you will see that they are full of this mica and
very small feldspar crystals. When you see this stuff sparkling in
the streams of Colorado you think you have found the mother lode.
My guess is that it is the micro version which is good because it
will be easier to grind and size.
As you know Mica is a layered alumino-silicate that has an
extremely high melting point. It is going to look much like clay in
the chemistry. Since you are firing at relative low temperatures,
cone 08-06 you might find small amounts of finely ground mica
valuable to help prevent a glaze from running. The down side of
this is that you can accomplish the same thing with clay which
also helps to keep your glaze in suspension in the bucket. I am
just doing a lot of wild guessing here because I have not been able
to find much about Mica in any of my books, but you might try
suspending larger particles of mica in a clear glaze base. they
should not melt or really effect the glaze melting much if the
particles are large, say 50 mesh. The suspended particles might
do some cool things with the reflected and refracted light from the
glaze surface. Start with about 1% because this stuff is very light
and work up or down based on what you see. The only down side
that I can imagine from adding Mica to a glaze is that you might
get some localized gassing around each particle. If this happens
try slowing your firing and see if this will go away.
W. Lowell Baker
The University of Alabama
Undetermined origin c/o LISTSERV administrator on fri 12 jan 01
In New Mexico they made bean pots out of them, I've just used it for
non-functional ware.
Karin
Laughing Bear Pottery
vince pitelka on sat 13 jan 01
> Mica does sound like a wonderful material. I had no idea it would allow me
> to make pieces I could use on my stove top.
>
> I wonder if the stove-top thing would work with ^6 clay, or is it only
> suitable for earthenware? Maybe it would work with ^6 paper clay, if not
> with the pure, dense stuff. I wonder if glazes will spoil the effect?
Sounds
> like fun.
The issue of stove-top ware has been discussed recently on Clayart.
Low-fire stove top ware is not a problem. If it fails, it will just drain
the contents all over your stove. A mess, but not life-threatening. But I
would definitely shy away from any midrange or high-fire stove-top wares.
A number of studio potters in the Northeast lost everything because of
lawsuits after "flameware" in stove-top use exploded from impacted moisture,
seriously injuring people. Doesn't seem to me that it is worth the risk.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dekalb.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
iandol on sat 13 jan 01
Dear Melinda,
A lot will depend on the chemistry of you mica mountain and how fine you =
can mill it.
There are many varieties of mica but all contain some form of essential =
low melting point flux.
If you can get it broken down to less that #100 it may be of use as an =
auxiliary flux in a glaze and a filler in a clay.
Muscovite has Potassium; Lepidolite, Lithium; Biotite, =
Potassium,magnesium and Iron.
If you can get it run through a mill and collect a sample then run some =
line blends.
Best regards,
Ivor
Khaimraj Seepersad on sat 13 jan 01
Greetings to all ,
Melinda ,
you can use the mica for making Egyptian Paste Bodies ,
Glaze additive , a Frit if you use B203 [ the joys of having
a ball mill ] .
Also plasticize the mica [ at -200 mesh ] with Bentonite
and make pots . These can be rapidly dried in the test
kiln [ 4h x 6 x 6 " internal ] without cracking .
Add into bodies for the sparkle , can't say anything for the
thermal shock resistance , haven't tried that .
Also opens the bodies easily .
Available in many colours and as whole mountains ,
easy access [ down here ] .
I have even found small quantities of soft mica going to
clay . Fired to just off white .
Jade -
I ground up some Jadeite and floated with Bentonite .
100 gms Jade / 5 % Bentonite .
Applied thinly .
At 1180 deg.c the off white jade powder became a
glass. Very shiny , slight iron stain and beyond knife
hard . A thin glassy glaze.
Since I make an Artificial G.Borate , I will now add
10 , 20 and 30 % GB to 90 , 80 and 70 % Jadeite.
These are basic tests just to see what the melting is
like .
I am using the factor - 15 Na20 - 25 Al203 - 60 Si02
for the Jadeite.
Will send more as I go along .
Khaimraj
-----Original Message-----
From: Ron Collins
To: CLAYART@LSV.CERAMICS.ORG
Date: 13 January 2001 8:17
Subject: Re: mica
>Lowell, I was told also that it could have fluxing potential so will
>see...unfortunately, it requires 4WD and my little pickup can't go and we
>will have to wait until Ron goes "jade mining" again to get some quantity
of
>it. It's sheet mica-up to 2 inches..got some interesting effects last
>night...with the golden sand it's in, fired, it looks like little mounds of
>gold in a white glaze...only if it's sprinkled on top not in...it's a
>novelty for me,just playing around, I don't think much will come of it
>really...unless, like I was told, it makes pots so strong thermally, that
>they can just be fired in a campfire, fireplace situation....don't know
>anything much about micaceous clay, but it sounds interesting and when I
>looked it up on the net, it sure seems to go for a lot of money...they are
>proud of their micaceous clay in NM! Melinda
>
>___________________________________________________________________________
___
>Send postings to clayart@lsv.ceramics.org
>
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>
Cindy Strnad on sat 13 jan 01
Wow!
Mica does sound like a wonderful material. I had no idea it would allow me
to make pieces I could use on my stove top. And here we are with mountains
of it which Pacer (producer of Custer Feldspar) is frantically trying to
prevent from blowing away in the wind. (A health matter--not an economic
one) They don't sell it, or at least they didn't have a market for it last
time I asked. I'm going to head over there and beg some more. Right now, I
just have a gallon baggie they gave me to play with.
I wonder if the stove-top thing would work with ^6 clay, or is it only
suitable for earthenware? Maybe it would work with ^6 paper clay, if not
with the pure, dense stuff. I wonder if glazes will spoil the effect? Sounds
like fun.
Off to do some experimenting. . . .
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
earthenv@gwtc.net
http://www.earthenvesselssd.com
Michael McDowell on sat 13 jan 01
Melinda,
You asked about mica, and how it could be used in glazes. A complete answer
would be rather complex as the term "mica" refers to a class of around thirty
different minerals, and there are certainly more qualified people to address
that. The essential components of a mica type mineral seem to be Alumina,
Silica, and Potash. Then they may have additional components such as Magnesia,
Lithia, and Iron. The only mineral of this class that I have any experience
with as a glaze addition is Lepidolite, which supplies some Lithium as well as
the three basic components mentioned above. Lepidolite can be used as an
alternative to Spodumene as a source of Lithium in glazes, and both of these
are preferable to Lithium Carb. with it's solubility problems. Chances are
that your deposit is not Lepidolite though, unless it has a distinct lavender
or pink cast to it.
Micas tend to be highly resistant to heat and abrasion. This may make them
difficult to reduce to a fine enough particle size to be useful in glaze
without devising some kind of simple machinery to pulverize it. If you are
able to reduce particle size to a usable degree, then you should find the
material usable as at least a partial substitute for feldspar in glazes.
Again, at the level of "practical science" that you are approaching this from,
your best approach is to test it in your fire.
Michael McDowell
Whatcom County, WA USA
mmpots@memes.com
http://www2.memes.com/mmpots
Snail Scott on sat 13 jan 01
At 10:28 AM 1/13/01 -0700, you wrote:
>Mica does sound like a wonderful material.
>I wonder if the stove-top thing would work with ^6 clay, or is it only
>suitable for earthenware? Maybe it would work with ^6 paper clay, if not
>with the pure, dense stuff. I wonder if glazes will spoil the effect? Sounds
>like fun.
>
>
>Cindy Strnad
Those Jicarilla Apache micaceous beanpots are
seriously low-fire - probably lower than cones
go. Fired over an open fire in 20 minutes flat,
in the firings i've seen. From what I've heard,
the thermal-shock advantages would remain at
higher temps, but I couldn't guess about the
appearances, with or without glaze.
-Snail
Ron Collins on sat 13 jan 01
Please let me know when you complete more trials, if your jade is as fine as
mine, you will be pleasantly surprised with your glazes...Melinda
Ron Collins on sat 13 jan 01
only one way to know is to just try it...I will when we can get back up
there...and I'd really be interested to hear your results...you know, I read
somewhere that one of the pre-columbian pyramids down here had about half
way up, a full mica layer separating the bottom part of the pyramid from the
top part, no one yet seems to know why they took the trouble to make a whole
mica layer in a pyramid...we will never know....Melinda.
Ron Collins on sat 13 jan 01
Michael, you are right about my "level of science"..I will pursue this
though, because I think that not so much has been done that we couldn't
enjoy some new trials and experimentation.....it's just trying to get back
up there on the burro trail to get it...as far as the earthquake, we were
mostly worried about how the house would move as a unit, which it mostly
did, and that our underground concrete holding tank for water would not
fracture and our underground plumbing the same...the pump isn't running all
the time, so we assume we don't have any leaks...nothing like putting all
your eggs in one basket down here...it's a little more "living on the edge"
than I am comfortable with, but I can make $100/mo. in clay, so what am I
worried about? Melinda
Ron Collins on sat 13 jan 01
Cindy, I don't know much, but I know that since being here, I've made bean
pots just for fun for the gas stove top out of just earthenware but I only
glazes the lid handle and pot handles just for looks, here they use unglazed
ones, but the comals-huge earthenware platters used over wood fires for
tortillas, and fired on an open fire on top of the ground..are coated with a
ground up soapstone-called "chistun" that makes a low-tech "teflon" so the
food won't stick--I put terra sig on my bean pot but no glaze, because I
think it would cause the pot to crack, and so far it hasn't ....I tried
drying out clay on a above mentioned comal, I can't get decent plaster
here...but it wouldn't absorb the water, so I guess the ground up soapstone
does work...as far as bacteria in the beanpot after washing...well I use
antibacterial soap on just my primitive cookware-not on everything else-then
no problem.....Melinda who never wanted to be low-tech
Cindy Strnad on sun 14 jan 01
Hi, Vince
Don't worry, I wouldn't dream of selling flame ware, but I should have made
that clear. I would like to be able to make it, though--just for fun.
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
earthenv@gwtc.net
http://www.earthenvesselssd.com
Michael McDowell on sun 14 jan 01
Melinda,
Please don't think that I'm in any way demeaning your efforts when I speak of
the "level of practical science" at which you are operating. I'm only saying
that given that you are approaching the development of glazes using local
materials without resort to chemical analyses and glaze calculation software,
there is limited value in discussing the "mights". What your local variety of
Mica might have as constituent molecules, and how these might serve in a glaze
formula is all very good to know, but far more important to you is what it
actually behaves like in your firing regime. Test, test, test!
One word of caution though. It is apparently not uncommon for Fluorine to also
be bound up in the Mica molecule. This would become volatile in your bisque
fire, and probably not be a problem to finished results, but do make sure your
kiln is vented away from your work space...
Good luck,
Michael McDowell
Whatcom County, WA USA
mmpots@memes.com
http://www2.memes.com/mmpots
P.S. About the mid-level layer of mica in the pyramid. I wonder if it could
have anything to do with earthquake resistance? It might function similarly to
the Teflon bearings that they are using under some buildings to let them
"float" in a earthquake.
Aebersold, Jane F on sun 14 jan 01
While looking through our library holdings, I ran across this book title,
which I thought might be of interest to those of you who have been
discussing mica in clay--
All That Glitters: The Emergence of Native American Micaceous Art Pottery in
Northern New Mexico by Duane Anderson, published by the School of American
Research Press, 1999, Santa Fe, New Mexico
Best Regards, Jane
jane@ou.edu
Ron Collins on sun 14 jan 01
Michael McDowell,
You don't have to explain...I'm not that sort of person to look for
motives other than just the most obvious....so forget it...anyway, my kilns
are in the same structure with everything else, but it only has walls on
three sides, it's open air except for the roof....so I just assume, if I'm
not out there, since I do most firing at night, I'm ok....thanks for the
information though, I've never had very safe work habits....we are having
what I hope are just aftershocks right now...am firing kiln so hope it's not
more...thanks for your input, I know that you have worked with local
materials and found them interesting for years...and I won't bore you with
trivial info, but if I get something really interesting, I'll write , other
than that, I think I'll stay off a while, Melinda
Thom Mead on mon 15 jan 01
Dear Clayarters:
Having received a great amount (and quality) of advice on
studio cleanliness obsession, try this one:
I plan to go to grad school at age 51.
Am I completely crazy to do this?
All opinions are needed!
diane in Georgia
_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com
Frank Gaydos on mon 15 jan 01
Dear Diane,
"Follow your Bliss"
Joseph Campbell
Frank Gaydos
----- Original Message ----- >
> I plan to go to grad school at age 51.
> Am I completely crazy to do this?
>
> All opinions are needed!
>
> diane in Georgia
>
>
Logan Oplinger on tue 16 jan 01
Ron,
Mica is a general name applied to a group of silicate minerals called phyllosilicates which have the ability to be split into very thin sheets. Of the group, the rarer lepidolite is the one of most interest for use as a glaze ingredient because it contains lithium as well as some of the other fluxing elements (K, Na, Mg, etc.). From your description, the type of mica you may have is muscovite which is one of the more common. The
simple composition is K20 3Al203 6SiO2 (with some hydrogen and fluorine that would be expelled as water vapor and hydrofluoric acid when heated to glaze temperatures). For evaluating as a glaze ingredient, the Segar formula would be K20=1, Al203=3, SiO2=6 ignoring any other combined elements in minor amounts. Because of the high silica and very high alumina content, (approaching kaolin in composition - Al203 + 2SiO2) muscovite may be useable only as a glaze modifier rather than as a main ingredient.
Go to the following web pages for more info. on the mica group of minerals:
http://www.mineralminers.com/html/mcaminfo.htm
http://mineral.galleries.com/Minerals/Silicate/Micas.htm
I'm sure someone else will have more to say about this, either to correct errors or adding what I've forgotten.
Logan Oplinger
---- you wrote:
> I am firing the test kiln now, trying some things, but would like to put the question out, and hopefully someone may help me out, as I have never been a glazemeister...of what use, if any, is mica as a glaze material? I know of, but have never seen, micaceous clay pottery, but does it have any other uses? Ron knows where a mountain of it is, free for the taking by the side of the dirt road, in the mountains of Guatemala, and he says at 8 am it looks like a mountain of gold....has anyone used it for anything, ceramic/wise, except as a clay addition? Melinda
>
> ______________________________________________________________________________
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>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
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>
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Andi Fasimpaur on thu 17 may 01
I've used mica as temper in clay, as an additive to
glaze, and burnished into the surface of pots... I've
grown, over the last couple of years to love the look
and feel of mica, especially in a pit fired pot where
the mica glints like stars in the night sky.
The really fine mesh mica isn't exactly what I was
looking for, It's nice mixed with iron oxide to be
applied as a wash over texture, or with stains or
underglazes for the same purpose, I also like brushing
a mixture of 325 mesh mica and cornstarch onto a slab
before impressing really detailed textures, it forms a
nice release...
If you're interested in mica as temper and want to
keep some of the qualities of the mica, I would
recommend ordering from one of the southwestern
suppliers. What I've seen is a clean white mica, just
the sight of it makes me smile...
Andi
giddy with sparkling pots...
=====
Ceramic Artist and Sculptor, Workshop Facilitator, and Dayton Area Co-Ordinator for the Goddess 2000 Project. Visit http://www.goddess2000.org for more information about the project and its goals.
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Andi Fasimpaur on sat 21 jul 01
greetings,
I've been reading the thread on micaceous clays
with a great deal of interest. Here are my
thoughts, in no particular order:
Vermiculite, as I understand it, is expanded mica.
There is a lot of air trapped in the vermiculite
(part of the reason that it is so light). The
silver clay people used to recommend firing hollow
forms in a bed of vermiculite so that they wouldn't
collapse under their own weight. The current
recommendation is that you fire them in a bed of
alumina hydrate (which, like the vermiculite, can
be re-used) the reasoning behind this has something
to do with an EPA alert about asbestos fibers in
some vermiculite products... I got the info at
http://www.pmclay.com/v34vermiculite.html
Asbestos concerns aside, since there is so much
air in the vermiculite from the expansion, it would
seem to me that all of the problems people have
described would make sense... But vermiculite and
mica really are quite different things.
Crushed mica makes a wonderful temper for primative
pottery. The sparkles are delightful on a burnished
pot that is smoked or pit fired. The mica I've used,
purchased through Pacer or through New Mexico Clay or
Terra Hermosa (I think), has all turned golden in
reduction. You can order a fine mesh mica from many
ceramics suppliers, approx 200 mesh, which is wonderful
mixed with iron oxide or black underglaze for a wash
on unglazed textured surfaces. I've fired it to cone
6 with no problems, my experiments with cone 10 led
me to believe that the mica will melt at those temps.
I often use a dusting of fine mesh mica and corn
starch as a release. After rolling a slab which
I want to texture, I will brush the mixture of mica
and corn starch so that I can texture with non-porous
tools (ie rubber stamps, textured glass) I mix the
mica with the corn starch because it extends the mica
further, although there is no reason you couldn't use
the mica on it's own.
I also frequently burnish crushed mica (larger, from
new mexico clay or other sources) into the surface
of pots made with standard clays, in this way a little
mica goes a long way and I still get the delightful
sparkle. Coil build a pot, roll it around in a pie
plate filled with mica, burnish as usual... it looks
great and you don't have to worry about wedging the
mica in...
Of course these are my results, yours could vary, and
the fact that I work small (probably 95% of my
production is less than 3 cubic inches) may give me
different results than others would have working on
a larger scale... Whatever the case, I love working
with mica, I love the glitter and sparkle, I love
the golden flecks, and the way that it looks under my
lowfire soup kitchen glaze after we pit fire it...
For an additional source of mica, try contacting an
electronics surplus house, they will frequently have
mica washers used for insulation on circuit boards,
these wonderful disks of mica can be split with a
scalpel until they are thinner than paper, and then
pressed into clay, they're surprisingly flexible.
Good luck and best Wishes!
Andi.
ps, I'm running behind with my email, if you've written
and I haven't gotten back to you, please forgive me, I
promise that I will write soon, we're moving the studio.
=====
Ceramic Artist, Writer, Workshop Facilitator.
http://www.mysticspiral.com
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Ivor and Olive Lewis on tue 9 sep 08
Dear Lili,
It is most probable, if the colour of the powder is white or pale
grey, that this will be Muscovite Mica, a complex Alumino-silicate
material that is rich in Potash. This makes it a useful high
temperature Body Flux.
Recommended it this weekend to our house guest who wished to enhance
the vitrification of a native refractory stoneware clay he has
collected from Kangaroo Island.
I used it as an additive to clay which was being salt glazed.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
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