David Hewitt on sat 8 nov 03
Mike,
From a limited test that I did a couple of years ago with a single glaze
the answer was, yes. It appeared to look the same.
The recipe in question had sufficient silica in it to enable me to only
alter this when changing from spodumene to petalite to obtain the same
amount of lithium.
David
In message , Mike Martino writes
>Hello All,
>
>Glaze newbie question I have and was wondering if anyone can share their
>experiences. Has anyone ever tried to substitute petalite for spodumene
>(adjusting for the SiO/Al ratio) as the main source of lithium in a glaze?
>What were the results? In retrospect, was it all in all a bad idea? Tweaking
>aside, just want to make sure there aren't any unforeseen catastrophic
>occurences waiting around the bend before I begin.
>
>I'm in Japan, and the supplier here told me after looking in his catalog
>that although the mineral name for spodumene shows up in his list, there is
>no product associated with it. They do have something called "Lithiaflux" (a
>damnable direct translation from the Japanese word, sorry) which I think is
>petalite.
>
>
>Thank you,
>
>Mike Martino
>Taku, Japan
--
David Hewitt
David Hewitt Pottery
South Wales UK
Web:- http://www.dhpot.demon.co.uk
Tony Hansen on sat 8 nov 03
Check here:
http://digitalfire.ab.ca/cermat/ceramicmaterials/material.php?id=1287
and here:
http://digitalfire.ab.ca/cermat/ceramicmaterials/material.php?id=1114
The chemistry is quite different.
Spodumene has twice as much lithium and a lot more alumina.
-------8<--------
Mike,
>From a limited test that I did a couple of years ago with a single glaze
the answer was, yes. It appeared to look the same.
The recipe in question had sufficient silica in it to enable me to only
alter this when changing from spodumene to petalite to obtain the same
amount of lithium.
David
In message , Mike Martino writes
>Hello All,
>
>Glaze newbie question I have and was wondering if anyone can share their
>experiences. Has anyone ever tried to substitute petalite for spodumene
>(adjusting for the SiO/Al ratio) as the main source of lithium in a glaze?
>What were the results? In retrospect, was it all in all a bad idea? Tweaking
>aside, just want to make sure there aren\'t any unforeseen catastrophic
>occurences waiting around the bend before I begin.
>
>I\'m in Japan, and the supplier here told me after looking in his catalog
>that although the mineral name for spodumene shows up in his list, there is
>no product associated with it. They do have something called \"Lithiaflux\" (a
>damnable direct translation from the Japanese word, sorry) which I think is
>petalite.
>
>
>Thank you,
>
>Mike Martino
>Taku, Japan
--
David Hewitt
David Hewitt Pottery
South Wales UK
Web:- http://www.dhpot.demon.co.uk
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Calculation/Database Software for Ceramic Industry
iandol on sat 8 nov 03
Dear Mike Martino,
I started using Lithium based minerals about ten years ago. At that time =
I tried Lepidolite, Spodumene and Petalite. Unfortunately I could not =
get hold of Amblygonite.
After some testing I chose Petalite for the purpose I had in mind, =
adjustment of Coeff. of Exp. Lepidolite did not mix in well, being a =
flake micaceous material. Spodumene seemed to make the glazed froth =
which caused pinhole problems and glazes need more fettling. Petalite =
worked fine and improved the brightness of the clear glazes, almost =
imitating Lead glazes but on stoneware and porcelain
I like Petalite for adjusting Coeff of Exp. It has a high Silica to =
alumina ratio and adding more silicon dioxide helps alleviate the =
problem as does the lithium oxide. So, although expensive, being double =
fisted as it were, I get better value for my money.
Best regards,
Ivor Lewis. Redhill, South Australia
Mike Martino on sat 8 nov 03
Hello All,
Glaze newbie question I have and was wondering if anyone can share their
experiences. Has anyone ever tried to substitute petalite for spodumene
(adjusting for the SiO/Al ratio) as the main source of lithium in a glaze?
What were the results? In retrospect, was it all in all a bad idea? Tweaking
aside, just want to make sure there aren't any unforeseen catastrophic
occurences waiting around the bend before I begin.
I'm in Japan, and the supplier here told me after looking in his catalog
that although the mineral name for spodumene shows up in his list, there is
no product associated with it. They do have something called "Lithiaflux" (a
damnable direct translation from the Japanese word, sorry) which I think is
petalite.
Thank you,
Mike Martino
Taku, Japan
Ron Roy on sun 9 nov 03
Hi Mike,
Just compared Ausi Spod with Petalite and it is does not have as much Li2O.
Ausi Spod has about 7.64 Li2O
Petalite has about 4.33%
Petalite has a lot more silica ans less alumina and less KNaO
Best to do the sub using calculation software - If you want me to do it
send me the recipe.
RR
>Glaze newbie question I have and was wondering if anyone can share their
>experiences. Has anyone ever tried to substitute petalite for spodumene
>(adjusting for the SiO/Al ratio) as the main source of lithium in a glaze?
>What were the results? In retrospect, was it all in all a bad idea? Tweaking
>aside, just want to make sure there aren't any unforeseen catastrophic
>occurences waiting around the bend before I begin.
>
>I'm in Japan, and the supplier here told me after looking in his catalog
>that although the mineral name for spodumene shows up in his list, there is
>no product associated with it. They do have something called "Lithiaflux" (a
>damnable direct translation from the Japanese word, sorry) which I think is
>petalite.
>Thank you,
>Mike Martino
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Bobbruch1@AOL.COM on sun 9 nov 03
<<<< I started using Lithium based
minerals about ten years ago. At that time I tried Lepidolite, Spodumene and
Petalite. Unfortunately I could not get hold of Amblygonite. After some testing
I chose Petalite for the purpose I had in mind, adjustment of Coeff. of Exp.
Lepidolite did not mix in well, being a flake micaceous material. Spodumene
seemed to make the glazed froth which caused pinhole problems and glazes need
more fettling. Petalite
worked fine and improved the brightness of the clear glazes, almost imitating
Lead glazes but on stoneware and porcelain. I like Petalite for adjusting
Coeff of Exp. It has a high Silica to alumina ratio and adding more silicon
dioxide helps alleviate the
problem as does the lithium oxide. So, although expensive, being double
fisted as it were, I get better value for my money.
I thought there was some difficulty in obtaining Petalite? Even if not, why
not use Lithium Carb? Is it a cost issue?
Bob Bruch
Dave Finkelnburg on sun 9 nov 03
Dear Bob,
To my knowledge there is no problem buying petalite, though it does cost
as much as a frit, about $1.25/pound in a 50-pound bag.
No, it isn't the cost of lithium carbonate, but the danger, that makes
it a problem.
Like many potters, at one time I bought lithium carbonate to test it as
a glaze ingredient. Knowing what I know today I must emphasize that, in my
biased opinion, lithium carbonate is NOT a raw material that should be in
any pottery studio. First, it is water soluble. Second, it can have
significant human health effects, either as the powder or when dissolved in
water.
Lithium carbonate of pharmaceutical purity is a prescribed medicine that
evens out mood swings for some individuals. The brain chemistry is complex,
but basically sodium isn't doing its job of conveying signals in the brain
for such folks and lithium, in a controlled level in the blood, steps in and
does the job.
An overdose of lithium can be toxic. So the powdered carbonate is
dangerous! So is the liquid phase of any glaze containing lithium. The
person most exposed to these hazards, of course, is the potter. Children
and pets who frequent the studio also are at risk.
Like sodium in soda ash, soluble lithium in a glaze solution is carried
by evaporating water. As the glaze dries the lithium accumulates where the
glaze dries last. This tends to concentrate the lithium in certain spots.
The potter does not necessarily have control over where those spots are.
Because lithium is such a low-expansion glaze ingredient, this can lead to
localized glaze shivering.
Your question is a good one. I think using petalite makes good sense.
Great potting!
Dave Finkelnburg in Idaho, USA
----- Original Message -----
From:
Sent: Sunday, November 09, 2003 8:14 AM
> I thought there was some difficulty in obtaining Petalite? Even if not,
why
> not use Lithium Carb? Is it a cost issue?
Mike Martino on mon 10 nov 03
Dave,
Thank you so much for your very informative answer to my question. Every
answer I received was positive, so I'm going to give it a whirl.
Oddly, this stuff is comparatively cheap here, at about 80 cents a pound in
a 50 pound bag.
Thanks again,
Mike Martino
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of Dave Finkelnburg
Sent: Monday, November 10, 2003 2:40 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Petalite vs Spodumene?
Dear Bob,
To my knowledge there is no problem buying petalite, though it does cost
as much as a frit, about $1.25/pound in a 50-pound bag.
No, it isn't the cost of lithium carbonate, but the danger, that makes
it a problem.
Like many potters, at one time I bought lithium carbonate to test it as
a glaze ingredient. Knowing what I know today I must emphasize that, in my
biased opinion, lithium carbonate is NOT a raw material that should be in
any pottery studio. First, it is water soluble. Second, it can have
significant human health effects, either as the powder or when dissolved in
water.
Lithium carbonate of pharmaceutical purity is a prescribed medicine that
evens out mood swings for some individuals. The brain chemistry is complex,
but basically sodium isn't doing its job of conveying signals in the brain
for such folks and lithium, in a controlled level in the blood, steps in and
does the job.
An overdose of lithium can be toxic. So the powdered carbonate is
dangerous! So is the liquid phase of any glaze containing lithium. The
person most exposed to these hazards, of course, is the potter. Children
and pets who frequent the studio also are at risk.
Like sodium in soda ash, soluble lithium in a glaze solution is carried
by evaporating water. As the glaze dries the lithium accumulates where the
glaze dries last. This tends to concentrate the lithium in certain spots.
The potter does not necessarily have control over where those spots are.
Because lithium is such a low-expansion glaze ingredient, this can lead to
localized glaze shivering.
Your question is a good one. I think using petalite makes good sense.
Great potting!
Dave Finkelnburg in Idaho, USA
----- Original Message -----
From:
Sent: Sunday, November 09, 2003 8:14 AM
> I thought there was some difficulty in obtaining Petalite? Even if not,
why
> not use Lithium Carb? Is it a cost issue?
____________________________________________________________________________
__
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
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Ron Roy on mon 10 nov 03
Hi Bob,
There are some solubility issues with Lithium Carb - and the soluble part
migrates through the body as the glaze dries giving strange fit problems
sometimes. Best to keep it at 2% or less.
I have seen both crazing and shivering on ware with higher amounts of
Lithium Carb.
It can also defloc glazes because of the solubility.
Proceed with cauction and test any lithium Carb bearing glazes well for fit
problems.
RR
><<<< I started using Lithium based
>minerals about ten years ago. At that time I tried Lepidolite, Spodumene and
>Petalite. Unfortunately I could not get hold of Amblygonite. After some testing
>I chose Petalite for the purpose I had in mind, adjustment of Coeff. of Exp.
>Lepidolite did not mix in well, being a flake micaceous material. Spodumene
>seemed to make the glazed froth which caused pinhole problems and glazes need
>more fettling. Petalite
>worked fine and improved the brightness of the clear glazes, almost imitating
>Lead glazes but on stoneware and porcelain. I like Petalite for adjusting
>Coeff of Exp. It has a high Silica to alumina ratio and adding more silicon
>dioxide helps alleviate the
>problem as does the lithium oxide. So, although expensive, being double
>fisted as it were, I get better value for my money.
>
>I thought there was some difficulty in obtaining Petalite? Even if not, why
>not use Lithium Carb? Is it a cost issue?
>
>Bob Bruch
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
iandol on mon 10 nov 03
Dear Bob Bruch,
I have no problem obtaining Petalite. Buy it by the 25 kg bag and save a =
bundle. My supplier is The Pug Mill in South Australia =
pugmill@pugmil.com.au . I think this mineral is mined by Sons of Gwalia =
in West Australia. Great stuff, works wonders.
As I said, it combines two things which mitigate crazing.
Yes, it is lower in Li2O than some other minerals but it is higher in =
Silicon Dioxide so I get a better glass. And it is much less expensive =
than Lithium Carbonate which has some problems with solubility in water, =
if I read the values right, of more than 1 gram per litre.=20
Petalite: ball park figures are SiO2 77.00%, Al2O3 17.5%, Li2O 4.30%, =
KNaO 0.50%.
Hope that helps.
Ivor Lewis. Redhill, South Australia
Tony Hansen on mon 10 nov 03
If petalite only has 4% Li2O and it takes 10 times as much
to get the same amound of Li2O in the glaze. To replace
3% Lithium Carbonate takes about 30 petalite. This introduces
a lot of alumina which means you have to cut the kaolin or
ball clay drastically. If the glaze is already short of clay
you can end up with a glaze that will not suspend. In a glaze
having 25% kaolin I found the kaolin had to be cut to 11%, that
is not enough. One positive is that the quartz also needs to be
cut drastically.
-------8<--------
Dear David Hewitt,
I understand you have no fear of using lithium carbonate as a source for
lithium in your glaze. Why do you prefer the carbonate rather than
petalite?
-------
You can update your personal and affiliation info on our website:
http://digitalfire.com/services/register.php?password=solsopas
===============
Tony Hansen, http://digitalfire.com
Personal Contact Page: http://digitalfire.com/services/contact.php?pwd=solsopas
Calculation/Database Software for Ceramic Industry
Tony Hansen on mon 10 nov 03
Are you sure about this?
Shivering that I have seen is on edges of pieces
and all edges were affected. How could lithia on
the surface of a glaze could make the
entire thickness shiver.
Also, just how soluble is lithium carbonate, I
think I will try to find out. I have had lithium
glazes that have crystallized in the past but then
when I ball milled them again they did not recrystallize,
at least not that I remember.
Does anyone know of a high lithium frit?
The highest one I know of is Fusion F-493, it is
11% Li2O.
------8<--------
Like sodium in soda ash, soluble lithium in a glaze solution is carried
by evaporating water. As the glaze dries the lithium accumulates where the
glaze dries last. This tends to concentrate the lithium in certain spots.
The potter does not necessarily have control over where those spots are.
Because lithium is such a low-expansion glaze ingredient, this can lead to
localized glaze shivering.
-------
===============
Tony Hansen, http://digitalfire.com
Personal Contact Page: http://digitalfire.com/services/contact.php?pwd=solsopas
Calculation/Database Software for Ceramic Industry
David Hewitt on mon 10 nov 03
In message , Dave Finkelnburg writes
> Like many potters, at one time I bought lithium carbonate to test it as
>a glaze ingredient. Knowing what I know today I must emphasize that, in my
>biased opinion, lithium carbonate is NOT a raw material that should be in
>any pottery studio. First, it is water soluble. Second, it can have
>significant human health effects, either as the powder or when dissolved in
>water.
Please excuse me if I use this particular item to express another point
of view as I feel that too often postings to Clayart are over cautious.
In my opinion there is no problem in having Lithium carbonate in my
studio. If you know of the hazards and the proper precautions to take,
then it is OK. We are handling all sorts of other materials with various
potential hazards. Not least being the dust from the clay and other
materials that is an inevitable consequence of our work. If one drives a
car one is at much greater risk, but does one stop driving because of
this?
As to the other particular aspects mentioned, the water solubility is
small and in the quantities used in any recipe, this is not in my
experience a problem. Also I do not consider that there is any risk
whatsoever to the final user of the item if the glaze is well
formulated. The amount of Lithium is going to be very small to start
with, I use one glaze regularly with 12 parts Lithium carbonate in 1000.
David
--
David Hewitt
David Hewitt Pottery
South Wales UK
Web:- http://www.dhpot.demon.co.uk
Dave Finkelnburg on mon 10 nov 03
Dear David Hewitt,
I understand you have no fear of using lithium carbonate as a source for
lithium in your glaze. Why do you prefer the carbonate rather than
petalite?
The carbonate is certainly more poisonous than the other alkali fluxes
sodium and potassium. According to my edition of the CRC Handbook of
Chemistry and Physics, the carbonate is also soluble in a glaze up to about
1.5% (more than you use in the glaze you cite below). This solubility can
lead to localized concentration of lithium in the glaze as it follows the
evaporating water from the glaze slurry. This can cause localized glaze
shivering. Both these are serious potential problems.
You are absolutely right, there is no need to be alarmist nor to fear
if, as you say, "...you know of the hazards and the proper precautions to
take...." Wouldn't you agree that using petalite as a source of lithium
rather than the carbonate is a proper precaution?
Good potting!
Dave Finkelnburg
----- Original Message -----
From: "David Hewitt"
Sent: Monday, November 10, 2003 1:14 PM
> In my opinion there is no problem in having Lithium carbonate in my
> studio. If you know of the hazards and the proper precautions to take,
> then it is OK.
>
> As to the other particular aspects mentioned, the water solubility is
> small and in the quantities used in any recipe, this is not in my
> experience a problem. Also I do not consider that there is any risk
> whatsoever to the final user of the item if the glaze is well
> formulated. The amount of Lithium is going to be very small to start
> with, I use one glaze regularly with 12 parts Lithium carbonate in 1000.
Edouard Bastarache Inc. on mon 10 nov 03
Tony,
Lithium carbonate is considered to be only slightly soluble in water.
It has a higher vapor pressure than the other alkaline carbonates.
(Ceramic Industry, 1983)
One gram dissolves in 78 ml cold, 140 ml boiling water; dissolved
by diluted acids. Practically insoluble in alcohol.
(The Merck Index, 2001)
Lithium is also present in a mineral named triphylite(LiFePO4),
besides spodumene, petalite, lepidolite and amblygonite.
Hope this helps.
Later,
"Ils sont fous ces quebecois"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
http://sorel-tracy.qc.ca/~edouardb/
http://perso.wanadoo.fr/smart2000/index.htm
http://www.digitalfire.com/education/toxicity/
Edouard Bastarache Inc. on mon 10 nov 03
Hello David & all,
for a comprehensive text on the toxicity of
lithium go to :
http://perso.wanadoo.fr/smart2000/index.htm
or
http://www.digitalfire.com/education/toxicity/
The information is available in french and english.
Later,
"Ils sont fous ces quebecois"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
http://sorel-tracy.qc.ca/~edouardb/
http://perso.wanadoo.fr/smart2000/index.htm
http://www.digitalfire.com/education/toxicity/
David Hewitt on tue 11 nov 03
Dave,
In message , Dave Finkelnburg writes
>Dear David Hewitt,
> I understand you have no fear of using lithium carbonate as a source for
>lithium in your glaze. Why do you prefer the carbonate rather than
>petalite?
I was not saying that I preferred lithium carbonate to either petalite
or spodumene, but that I saw no real problem in using lithium carbonate.
I was, as I indicated, using this particular thread to express the view
that threads on Clayart are at times too alarmist. When you said with
emphasis that:-
'Knowing what I know today I must emphasize that, in my
biased opinion, lithium carbonate is NOT a raw material that should be
in any pottery studio.'
I thought that it warranted some comment. I see no problem in avoiding
ingesting or inhaling this or other materials and so do not think that
Lithium carbonate warrants the exclusion that you advocate.
On other practical grounds it is not always possible to substitute
petalite or spodumene and maintain the some molecular analysis because
of their alumina and silica contents, but my real reason for commenting
is that expressed in the paragraphs above.
David
--
David Hewitt
David Hewitt Pottery
South Wales UK
Web:- http://www.dhpot.demon.co.uk
Snail Scott on tue 11 nov 03
>Dave F. wrote:
>>As the glaze dries the lithium accumulates where the
>>glaze dries last. This tends to concentrate the lithium in certain spots.
>>...this can lead to
>>localized glaze shivering.
At 10:39 AM 11/10/03 -0500, Tony H. wrote:
>Are you sure about this?
>Shivering that I have seen is on edges of pieces
>and all edges were affected. How could lithia on
>the surface of a glaze could make the
>entire thickness shiver....
This makes some sense to me, since when I see
scumming and other evidence of soluble materials
leaching to the surface during drying, it seems
to concentrate on the pointy edges of whatever
form is involved, not evenly across the surface.
Though shivering naturally evidences itself
most readily on such edges anyway, for reasons of
geometry and stress, it doesn't seem inconsistent
to suppose that a slight migration of dissolved
lithium to the same areas might exacerbate a
previously borderline problem.
-Snail
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