Nikom Chimnok on sun 24 nov 96
I would like to thank everyone who responded to my inquiry about how to dry
pots quickly. More than one person suggested adding grog to the clay body to
make it dry out faster without any elaborate equipment. This is an
interesting suggestion, because it would also make it possible to fire faster.
So now my question is, how to make good grog? I understand that it is
traditional merely to grind up cracked pots and use that for grog; but what
if you want to add 20% grog and don't crack 20% of your pots? Then you need
to produce grog. That is our situation.
What is the best grog? Should it be nearly vitrified clay, or will bisqued
clay work as well? When you buy grog, what is it like? Really hard, or just
bisqued? I am sorry to sound so stupid, but there is no grog for sale in
Thailand--the only grog I've ever seen is what I've made myself. How finely
should it be ground? I remember a recipe from Ceramics Monthly for sculpture
clay, calling for a mix of fine, medium, and coarse grog. What meshes do
those words correspond to? Are there problems associated with using grog?
Thank you in advance. Clayart is wonderful. The internet only came to our
city last week; it's exciting.
**************************
Nikom Chimnok
koratpot@loxinfo.co.th
**************************
Karen Gringhuis on mon 25 nov 96
Grog mesh size - coarse = 4 - 16 mesh; medium = 20-36 mesh; fine =
40 - 60 mesh.
Jon Pettyjohn on tue 26 nov 96
Hi Nikom,
Here in the Philippines we cannot buy ready made grog either. I have
been grinding cracked bisque for a long time with good results. I get
your point about needing 20% but not wanting to grind 20% of your
bisque. One solution is to fire your wheel trimming scraps. It makes
things even simpler if you grind them first. I've been using a corn
grinder which is commonly available around here. The only alteration
I did was to change the motor from a 1 hp to 2 hp, although it's
possible to smash bisque pots and grind in this machine it's a lot
easier to grind dry clay and fire in bowls afterward. I sometimes
fire a load of grog very fast in a small electric kiln.
It's important to grade the grog carefully. I usually sieve out
everything finer than 80 mesh and keep everything that passes through
a 40M. This is for my throwing clay, for a coarse handbuilding clay
you might go as large as 30M. The thing about handmade grog is that
we never have enough as it's not easy to make so I try to keep the
percentages to a minimum. I think around 8% is fine for a smooth
throwing clay. If you need to reduce shrinkage more than this I would
suggest you add other non-plastic materials. Sometimes porcelain
sanitary ware manufacturers grind to fine powder all their fired
rejects, sometimes they sell this material cheaply, it's called
"pitchers." High fired grog is better than low, but is even more
difficult to make, I sometimes use a mixture of half/half high ^9
and low ^010 and it works well.
I'd be curious to hear about the studio potters in Thailand. We see
so much of the Chiangmai Celadons, are there many contemporary
potters?
Jon Pettyjohn Manila clayjon@ibm.net
> ----------------------------Original message----------------------------
> I would like to thank everyone who responded to my inquiry about how to dry
> pots quickly. More than one person suggested adding grog to the clay body to
> make it dry out faster without any elaborate equipment. This is an
> interesting suggestion, because it would also make it possible to fire faster.
> So now my question is, how to make good grog? I understand that it is
> traditional merely to grind up cracked pots and use that for grog; but what
> if you want to add 20% grog and don't crack 20% of your pots? Then you need
> to produce grog. That is our situation.
> What is the best grog? Should it be nearly vitrified clay, or will bisqued
> clay work as well? When you buy grog, what is it like? Really hard, or just
> bisqued? I am sorry to sound so stupid, but there is no grog for sale in
> Thailand--the only grog I've ever seen is what I've made myself. How finely
> should it be ground? I remember a recipe from Ceramics Monthly for sculpture
> clay, calling for a mix of fine, medium, and coarse grog. What meshes do
> those words correspond to? Are there problems associated with using grog?
> Thank you in advance. Clayart is wonderful. The internet only came to our
> city last week; it's exciting.
> **************************
> Nikom Chimnok
> koratpot@loxinfo.co.th
> **************************
>
>
Louis Katz on wed 27 nov 96
On Sun, 24 Nov 1996, Nikom Chimnok wrote:
> ----------------------------Original message----------------------------
> I would like to thank everyone who responded to my inquiry about how to dry
> pots quickly. More than one person suggested adding grog to the clay body to
> make it dry out faster without any elaborate equipment. This is an
> interesting suggestion, because it would also make it possible to fire faster.
> So now my question is, how to make good grog? I understand that it is
> traditional merely to grind up cracked pots and use that for grog; but what
> if you want to add 20% grog and don't crack 20% of your pots? Then you need
> to produce grog. That is our situation.
Dear Nikom,
Your clay is very sandy already,do your pots develop a skin of hard clay
as they dry or does the wall dry all the way through? If the clay skins
then grog may help, so might some finer nonplastic material. It could be
that you already have too much sand in you clay and that the sandy grog
will just make matters worse.I am not sure if you have cheap access to any
clays other than Dankwean Clay.
Has anybody tried making grog like they do
in Mahasarakham with cannon balls made mostly of rice hulls yet?
Have you tried adding 10% talc to your clay ever?. If you fire all the way
to cone 8 it may cause some problems but at slightly lower temperatures it
could help you some in terms of cracking. It might slightly
reduce your firing temperature and it might be a material you can afford.
> **************************
> Nikom Chimnok
> koratpot@loxinfo.co.th
> **************************
>
***************************************************
*Louis Katz lkatz@falcon.tamucc.edu *
*Texas A&M University Corpus Christi *
*6300 Ocean Drive, Art Department *
*Corpus Christi, Tx 78412 *
*Phone (512) 994-5987 *
**************************************************
Nikom Chimnok on wed 27 nov 96
At 07:50 26/11/96 EST, you wrote:
>----------------------------Original message----------------------------
>Hi Nikom,
>
>Here in the Philippines we cannot buy ready made grog either. I have
>been grinding cracked bisque for a long time with good results. I get
>your point about needing 20% but not wanting to grind 20% of your
>bisque. One solution is to fire your wheel trimming scraps. It makes
>things even simpler if you grind them first. I've been using a corn
>grinder which is commonly available around here. The only alteration
>I did was to change the motor from a 1 hp to 2 hp, although it's
>possible to smash bisque pots and grind in this machine it's a lot
>easier to grind dry clay and fire in bowls afterward. I sometimes
>fire a load of grog very fast in a small electric kiln.
>--------------------------------------------------------------------------
Greetings John,
Nice to hear from a fellow 3rd-worlder. I just wanted to mention a
grog-making trick that might help you, since you could probably get hold of
rice husks.
To make a high-fired grog, start with one measure of dry clay. Mix it with
water till it's a thin slip. Add three measures of rice husks. On top of
newspaper, or banana leaves, or whatever, spread this mix out in the sun to
dry, in cakes or loaves perhaps an inch thick. When dry, fire it hot in a
gas or wood-burning kiln. Rice husks are smoky and stinky--you wouldn't want
to do it in an electric kiln in your apartment. But it takes little fuel,
since the rice husks are fuel themselves.
When cooked, the loaves are so soft you can crush them with your
hands. Run this mix through your hammer mill (I assume that's what your corn
grinder is). It's easy to grind because the pieces are so small--just the
clay coating on the rice husks.
This certainly adds some rice husk ash to the mix, but the ash is
almost pure silica, not a bad thing in itself, and my calculations say it's
less than 1% of the total.
The method above is the way I've made grog in experimental quantities, and
it works good--especially a slip which is 30% grog. The bosses are not yet
convinced they could make it by the ton for a reasonable price this way, but
whenever I want to make something special, this is the way I do it. I've
tried powdering clay, as you mention, and then firing it, but when I fire it
really hot, it all sticks together again.
My experience is as yours: high-fired grog is best. I've tried
grinding red building bricks, which are fired to 6-700 degrees C. here.
They're easy to grind, but I'm not impressed with the clay which results.
>
Studio potters are few and far between in Thailand--most pottery is
made in large workshops, with division of labor. Sukothai celadons have
always been made by large commercial concerns. Pots by the containerload,
that's the only way to make money here.
>
**************************
>> Nikom Chimnok
>> koratpot@loxinfo.co.th
>> **************************
>>
>>
>
>
Guenter Haltmayer on thu 28 nov 96
Dear Nikom Chimnok, I wondered when I read your first mail where you would be
located - so its Thailand! Jon Pettyjohn gave you good advice, I think, and I
might just add some hints (but as I am not producing grog myself I am not
a real expert for this question).
First: the cheapest way to "open" a claybody is adding sand to the clay. But
this can be dangerous, of course, because sand is composed mainly of quartz and
if you add too much (max.20%) you might get problems with cooling cracks (due to
size change of crystals at 5730C and about 2300C) and your body may change in a
direction you don't like. The sand may also contain limestone or other minerals
like mica which may have other effects on the body... If you give it a try, test
some mixtures very carefully and search for a pure fine sand.
Secondly: a friend of mine used to produce his own grog (on a smale scale for a
studio of 2 persons), because he had so much rejects. He crushed the shards
first in a "stone crusher" to a particle size of 2-3 mm, then powdered it to
dust in a "hammer mill". The hammer mill is a machine used in agriculture, thus
the "corn mill" might be something similar or just the same machine.
The stone crusher is only needed if you have to cruh very hard shards, but this
can be done by manpower too. The higher fired grog the better, for sure, because
then shrinkage goes to zero. But the the hammer mill wears out very quickly, if
you feed it with vitrified clay, thus it is better to stay with lowfired grog.
There is a book, written by Henrik Norsker: "Clay materials - for the self
reliant potter" which is dedicated to potters in developing countries and gives
a lot of useful information about clay materials, preparation (but unfortunately
not so much on grog production) and so on.
It is written in English and published by the German development aid agency
GATE. Give nme a message, if you are interested and I search for he easiest way
for you to obtain a copy.
Yours Guenter
pedresel@3-CITIES.COM on wed 5 jul 00
The terra cotta I like for coiled flowerpots uses sand instead of grog.
Seems to keep the absorbancy down for frost resistance.
-- Evan in W. Richland WA where things are more or less back to normal
except we are having wonderfully not too hot weather and it actually
rained (in town anyway but not at home)
Cindy Strnad on wed 5 jul 00
Hi everybody,
I just got the shipment I ordered from the other side of the state (closest
place), and they forgot to send me the grog I ordered. The problem
is, I needed that grog, because I accidentally ordered un-grogged clay and
all my large pieces are developing unsightly cracks in the oddest places.
And the supply house owners are on summer vacation. And I need to make
some pieces which have been on order for a while. So what do I do? Can I use
silica sand? Something else? And if so, how much would you recommend?
Thanks,
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
earthenv@gwtc.net
Cindy Strnad on fri 7 jul 00
Thanks, Mia.
Yes, I'm sure they'll do that. It's just that they're on their summer
vacation, and I want it now! Tom Buck has been telling me how
to make my own, though, and I'm going to do that. I have an order I just
have to get out, and so I get to try something new.
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
earthenv@gwtc.net
Wade Blocker on fri 7 jul 00
Dear Cindy,
If you ordered grog and the supplier forgot to send it with your
order,just let them know, and they will send it to you separately, no
additional cost to you. I have yet to encounter a ceramic supply place that
fails to do that. Mia in ABQ
Snail Scott on sun 5 nov 00
The NARCO Ione grog is a quality product, but...
I LIKE firebrick grog! I like the color, I like the varied
particle size... and I like the price! Muddox Buff rules!
So there! ;P -Snail
At 12:59 PM 11/5/00 -0800, you wrote:
>Jonathan said:
>>The best substitute is a product called Mulcoa available from CE
>>Minerals in Georgia. (http://www.ceminerals.com/) It comes in many many
>>sizes and in 3 (I think) levels of alumina percentage. This is a
>>controlled, known formula calcine that will greatly surpass any "grog" type
>>material available in potters supply places.
>
>Hi:
>
>North American Refractories supplies Ione grain calcined kaolin in several
>meshes that is also a good grog source. I've used it in two different
>bodies with excellent results. You won't have to mortgage your kiln shed
>to buy it either.
>
>regards, Craig Martell in Oregon
>
>___________________________________________________________________________
___
>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.
>
Bill Patterson on sun 5 nov 00
I believe that the Ione grog products are a calcined product which is
sufficently controlled. It's true that brick factories use rejects in their
batches as a source for grog. These are usually rejected because of a color
difference. Such differences are insignificant and almost any potter
wouldn't even see the difference unless they were shown. I am not aware of
a packaged grog that is made from rejects.
----- Original Message -----
From: Craig Martell
To:
Sent: Sunday, November 05, 2000 1:59 PM
Subject: Re: Grog
> Jonathan said:
> >The best substitute is a product called Mulcoa available from CE
> >Minerals in Georgia. (http://www.ceminerals.com/) It comes in many many
> >sizes and in 3 (I think) levels of alumina percentage. This is a
> >controlled, known formula calcine that will greatly surpass any "grog"
type
> >material available in potters supply places.
>
> Hi:
>
> North American Refractories supplies Ione grain calcined kaolin in several
> meshes that is also a good grog source. I've used it in two different
> bodies with excellent results. You won't have to mortgage your kiln shed
> to buy it either.
>
> regards, Craig Martell in Oregon
>
>
____________________________________________________________________________
__
> 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.
>
Tom Wirt/Betsy Price on sun 5 nov 00
Another "virgin" grog is the Ione Grain series from North American
Refractories. Excellent stuff. Also, Christy Minerals grog is
virgin. Re: the recycling of firebrick, even worse is when a few
years ago, Maryland refractories bought brick from an old copper
smelter. The green specks that fired out ruined literally a hundred
pots for us, and most other potters in this area got some of it.
Complaints to the clay company brought no help....and they still use
Maryland Refractories grog.
The moral is...get to know your materials well....if you are making a
living at this game.
Tom Wirt
From: Jonathan Kaplan
Subject: Re: Grog
> Let's not forget that most of the "grog" that we use as
potters is
> nothing more then ground up firebrick culs, read "seconds." Now sure
they
> may be seconds for dimensional reasons, but they are also seconds
for other
> reasons having to do with the quality of the bricks themselves and
the
> materials that go into their making. Now I don't know about you, but
I work
> too hard to have this waste material in my clay bodies to wreck
havoc on my
> ware.
>
> The best substitute is a product called Mulcoa available from
CE
> Minerals in Georgia. (http://www.ceminerals.com/)
Jonathan Kaplan on sun 5 nov 00
Let's not forget that most of the "grog" that we use as potters is
nothing more then ground up firebrick culs, read "seconds." Now sure they
may be seconds for dimensional reasons, but they are also seconds for other
reasons having to do with the quality of the bricks themselves and the
materials that go into their making. Now I don't know about you, but I work
too hard to have this waste material in my clay bodies to wreck havoc on my
ware.
The best substitute is a product called Mulcoa available from CE
Minerals in Georgia. (http://www.ceminerals.com/) It comes in many many
sizes and in 3 (I think) levels of alumina percentage. This is a
controlled, known formula calcine that will greatly surpass any "grog" type
material available in potters supply places. And yes it costs more, but the
results far outweigh the expense.
Jonathan
Jonathan Kaplan
Ceramic Design GroupLTD/Production Services
PO Box 775112
Steamboat Springs, CO 80477
(970) 879-9139 voice and fax
http://www.sni.net/ceramicdesign
UPS: 1280 13th St. Unit13
Steamboat Springs, CO 80487
Craig Martell on sun 5 nov 00
Jonathan said:
>The best substitute is a product called Mulcoa available from CE
>Minerals in Georgia. (http://www.ceminerals.com/) It comes in many many
>sizes and in 3 (I think) levels of alumina percentage. This is a
>controlled, known formula calcine that will greatly surpass any "grog" type
>material available in potters supply places.
Hi:
North American Refractories supplies Ione grain calcined kaolin in several
meshes that is also a good grog source. I've used it in two different
bodies with excellent results. You won't have to mortgage your kiln shed
to buy it either.
regards, Craig Martell in Oregon
Ceramic Design Group on sat 26 jan 02
With some of the discussion lately regarding grog, lets not forget that the
"grog" that most of us are familiar with is made from ground hard firebrick
culls(seconds).This product is ground to various mesh sizes.
Basically, I have avoided these products for years. Why would I want ground
up rejected firebricks in my clay bodies? And yes I know that many bricks
are rejected for not being dimensionally accurate, but I don't want any
impurities in my clays that I can control.
So what is the solution? You want some degree of "tooth" (what is that
anyway...cuspids, bicuspids, quite incisive?)
There are 2 products on the market that I would recommend because I have
used them for years. They will add slightly to the cost of a clay body, but
they are very clean and always of a consistent formula.
These are "known formula refractory calcines." A refractory formula is made
and fired to a high temperature and then ground to various consistent mesh
sizes. They add strength to the claybody and give the tooth that some like.
Most of these products go to the refractory industry.
One product is called Mulcoa and is available from CE Minerals and works
very well in stoneware clay bodies. It is available in many many sizes. I
have not seen it available from any pottery suppliers. Request samples and
order direct, and then urge your clay manufacturers to use it. There will be
an increased cost.
The second product is Molochite, use in white bodies. It is an import from
the UK and is available from many ceramic suppliers.
Both these products are SUPERIOR to what is marketed as "grog" to clay
workers.
Jonathan
Jonathan Kaplan, president
Ceramic Design Group
PO Box 775112
Steamboat Springs CO 80477
voice and fax 970 879-9139
info@ceramicdesigngroup.net
Plant Location:
1280 13th Street Unit 13
Steamboat Springs CO 80487
(please use this address for all deliveries via UPS, comman carrier, Fed Ex,
etc.)
"Custom design and manufacturing for the ceramic arts, giftware and pottery
industries. Molds, models, and tooling for slip casting, jiggering and
hydraulic pressing. Consultation on clay and glaze formulation, production
systems,firing, and kilns.
iandol on sun 27 jan 02
Dear Jonathan,
I have always been concerned about the use of grog. In the glass =
industries there is a lot of recycling, scrap going back into to kiln as =
a way of helping to reduce fuel costs and I am certain this is done in =
the heavy clay industries for the same reasons.
My main concern, as I pointed out to Melinda in a recent posting, is =
that what has been reclaimed as grog may have been glazed. This then =
introduces an additional body flux into the clay so neither the =
manufacturer nor the user have any control.
Molochite solves this problem as does the product you suggest. Firebrick =
is rather a portmanteau term since nothing is said about the ratio of =
silica to alumina or if there is an excess of free silica in the =
composition, nor the mineral composition.
Thank you for your comments on this topic.
Best regards,
Ivor.
Snail Scott on mon 28 jan 02
At 05:54 PM 1/27/02 +1030, you wrote:
>I have always been concerned about the use of grog. In the glass
industries there is a lot of recycling, scrap going back into to kiln as a
way of helping to reduce fuel costs and I am certain this is done in the
heavy clay industries for the same reasons.
Most commercial grogs (I'm thinking Ione, Calamo and
similar products) are closely controlled in manufacturing,
and are used by industries with far tighter quality
controls than studio pottery.
On the other hand, I LIKE the ground-up firebrick grog.
It does the job of making my clay stand up well, dry
evenly, and shrink less, and I prefer the look of it.
The irregularity has never been a hindrance to my work.
-Snail
Philip Poburka on tue 29 jan 02
Uhhh...because the 'little-tiny' rock is 'little-tiny'...?
----- Original Message -----
From: "Bill Hanke"
To:
Sent: Tuesday, January 29, 2002 11:09 AM
Subject: grog
> If you wrap clay around a big rock it will dry, shrink, crack and fall
off.
> Why doesn't it do this with a little tiny rock, ie. grog?
> Aloha,
> Bill Hanke
> Maui
>
>
____________________________________________________________________________
__
> 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.
Bill Hanke on tue 29 jan 02
If you wrap clay around a big rock it will dry, shrink, crack and fall off.
Why doesn't it do this with a little tiny rock, ie. grog?
Aloha,
Bill Hanke
Maui
Jon Pacini on thu 31 jan 02
greetings all----Bill wrote----
> If you wrap clay around a big rock it will dry, shrink, crack and fall
off.
> Why doesn't it do this with a little tiny rock, ie. grog?
> Aloha,
> Bill Hanke
> Maui
Actually if the grog gets much bigger than split pea size the clay will
usually crack as it shrinks during drying and definitely during bisque
firing. Sometimes even causing pop offs if the bisque is "soft". a very
similar effect to that of lime pop offs.
Jon Pacini
Clay Manager
Laguna Clay Co
Paul Herman on thu 31 jan 02
John,
Laguna's catalog lists grogs as BUFF, IONE, and RED BRICK. Can you give
us a description of these materials? Also, what about kyanite and
mullite? Are they usable as "grog"?
Thanks,
Paul in Doyle, California
----------
>From: Jon Pacini
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: grog
>Date: Thu, Jan 31, 2002, 10:11 AM
>
> Jon Pacini
> Clay Manager
> Laguna Clay Co
gshaffer on fri 1 feb 02
When clay with grog is viewed under an electron microscope even the grog
we potters usually use has starlike patterns of cracks radiating out
from each piece of grog after firing. Some think this eventually leads
to cracking and failure of ovenware do to a connecting of the dot
theory.
Gary
Lili Krakowski on mon 28 may 07
Grog has its uses, and one can of course make one's own, although what I
always like about commercial grog is that its color is different from that
of my clay body.
However. Silica sand, which is available from people who sell brick and
cement and flue liners and so on to builders works very well instead of
grog. In fact Paul Soldner uses sand instead of grog, and explained why at
a workshop of his in Charleston. He said --and showed--that when you make a
coil out of grogged clay, and bend it into a loop, tiny spaces appear
around the bits of grog. When you make a coil out of clay with sand, there
are no little holes.
Also, of course...grog absorbs water, so if you need to wedge it in it will
dry your clay, while sand does not absorb water.
Also: you can, and I have, used crushed soft fire brick as grog...
As to chicken grit. You know how plucky chicken are? Plucky, plucky
plucky, and always have yolks to tell, and something to crow about? Well
the reason is that they eat chicken grit. (Eggtully, birds, for some
reason, need to eat something indigestible to help their tiny tummies digest
all the other yummies they eat. If they cannot roam around the yard and
pick up "grit" from the earth, they have to be fed the stuff.
Lili Krakowski
Be of good courage
Ron Roy on mon 28 may 07
Silica sand can have it's own problems. As does any quartz - it goes
through the quartz inversion during heating and cooling at 573C. If you are
having a bisque dunting problem - it is usually the free quartz in the clay
that is contributing to the problem.
On the other hand - Tuckers mixes several clay bodies with fine silica sand
and I don't know of any problems.
Didn't I hear that most chicken grit now has some CaO in it - not what you
want in a body if you don't want lime pops. Test it first - bisque fire and
soak.
I do make my own grog out of trimming scraps - the body is the same so
after the firing it is all the same.
RR
>Grog has its uses, and one can of course make one's own, although what I
>always like about commercial grog is that its color is different from that
>of my clay body.
>
>However. Silica sand, which is available from people who sell brick and
>cement and flue liners and so on to builders works very well instead of
>grog. In fact Paul Soldner uses sand instead of grog, and explained why at
>a workshop of his in Charleston. He said --and showed--that when you make a
>coil out of grogged clay, and bend it into a loop, tiny spaces appear
>around the bits of grog. When you make a coil out of clay with sand, there
>are no little holes.
>
>Also, of course...grog absorbs water, so if you need to wedge it in it will
>dry your clay, while sand does not absorb water.
>
>Also: you can, and I have, used crushed soft fire brick as grog...
>
>As to chicken grit. You know how plucky chicken are? Plucky, plucky
>plucky, and always have yolks to tell, and something to crow about? Well
>the reason is that they eat chicken grit. (Eggtully, birds, for some
>reason, need to eat something indigestible to help their tiny tummies digest
>all the other yummies they eat. If they cannot roam around the yard and
>pick up "grit" from the earth, they have to be fed the stuff.
>
>
>
>
>Lili Krakowski
>Be of good courage
>
>______________________________________________________________________________
>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.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Ivor and Olive Lewis on tue 29 may 07
If Chooks and other fowls did not eat Grit they would lay shell-less =
eggs. they need a constant supply of shell grit which is why some birds =
really gorge themselves on snails. A good source of calcium.
Without teeth, they also have a bit of a problem masticating their food. =
So they collect stones and other hard stuff in their gizzards. The =
muscular contractions of this organ assist grit and stone to liquefy =
their food.
Information is never useless is it.
Best regards,
Ivor
Gary Navarre on wed 30 may 07
Hi Folks,
I suppose sand would work as a grog in lagging (done that) or a body, it's
got to if Soldner uses it, and I tried the A.R.T. Stoneware with silica sand
and found it caused scratches while trimming and left little "melt out
spots" in the glaze at real high temp. or white spots when cooler.
The last time I bought a clay sample from Roven Ceramics near Detroit
(Taylor, Mi.) and wanted some fine grog they sold me kyanite/mullite for the
substitute.
http://en.wikipedia.org/wiki/Kyanite
http://en.wikipedia.org/wiki/Mullite
I didn't know of any problem getting grog but I have been away for a while.
My Iron Mountain brick supplier never heard of it and I saved a little
palette sweepings cause it was there. Don't know how what Rovin sold me will
work but what the heck, it's only money and I get all I need from Wal*Mart.
Stay in there ah?
G in da U.P.
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