ccpottery@BELLSOUTH.NET on wed 13 aug 03
This has been niggling at me for years - here goes ....
If breathing silica dust is so dangerous, then do people who live near the ocean or a
sandy beach have a higher rate of lung problems??
Sand is silica .... the wind has to carry even the finest particles all the time ... the
residents breathe in all sizes of particles 24 hours a day.
What is the difference between that and our limited exposure in the studio?
Chris Campbell - in North Carolina - hope somebody has an answer !
Dave Finkelnburg on wed 13 aug 03
Chris,
The key to understanding your important question is studio exposure is
not necessarily limited. I do not know of any studies that compare studio
silica dust exposure to background silica dust levels. Sorry.
There is dust in the air we breathe, anywhere on the planet.
Fortunately, raindrops and snowflakes form on dust particles, thus tend to
scrub the air with every storm. There is no such natural air cleaning in
the studio, and you know we can kick up dust just walking around in the
spilled trimmings and dried slop spills.
Here in the Intermountain West, where wind-blown volcanic ash has
altered the geography, forming mounds 200-feet high in places, I suspect
farming, roads, high winds give us more silica dust exposure than ever dust
off a beach does. And it's the fine silica, the less than one micron size
stuff (incredibly small) that is harmful. Beach sand has the fines pretty
much washed out of it. Still, if we could afford to analyze the air in our
studios, I suspect it could be much dustier than the outdoors.
I would not worry about the dust at the beach...or in the yard...things
you can't control anyway...but I would wet-mop the studio and do all the
other things that keep dust down, the things we can control.
Good potting!
Dave Finkelnburg
----- Original Message -----
From:
> If breathing silica dust is so dangerous, then do people who live near the
ocean or a
> sandy beach have a higher rate of lung problems??
>
> Sand is silica .... the wind has to carry even the finest particles all
the time ... the
> residents breathe in all sizes of particles 24 hours a day.
>
> What is the difference between that and our limited exposure in the
studio?
>
> Chris Campbell - in North Carolina - hope somebody has an answer !
Phil Smith on wed 13 aug 03
Here in the San Gabriel Valley we have some large rock quarries.
Homes were built all around them. The air around them is apparently filled
with fine dust. I believe lawsuits have been filed. Not sure if there were
any actual cases of illness or just a bunch of people pissed at their own
ignorance at having purchased a home with perpetual silica cloud overhead.
Phil...
psci_kw on wed 13 aug 03
Chris:
Not a silly question at all!
I am by no means an expert, but I might be
able to shed some light for you.
It's a matter of concentration of exposure.
Beach sand is usually damp, and pretty stable,
except in cases of higher wind speeds;
better than 42 knots IIRC.
(I can't bring myself to use the "H" word,
being the season here for them.)
In the studio, your size limit of air space
enclosed would tend to "concentrate" your exposure
being that the silica "dust" is just that...
dust, and dry at that.
Living near the beach does carry it's own risks:
higher exposure to UVA and B(and don't forget
that both are reflected off the surface of the water
as well as streaming directly from the sun),
allergic reactions to calcified (?) shell and coral dusts, higher
concentrations of iodine and heavy metals in local foods,
and for some an increased risk of Multiple Sclerosis. (The
medical community is presently looking carefully at that for causality,
it might just be confined to South Florida.)
Silicosis is not unknown among the general population, though confined more
directly to persons in occupations like construction (concrete dust),
landscaping (dust in general), and of course, farming and mining.
Hope that helps,
Wayne in Key West
-----
> If breathing silica dust is so dangerous, then do people who live near the
ocean or a
> sandy beach have a higher rate of lung problems??
>
> Sand is silica .... the wind has to carry even the finest particles all
the time ... the
> residents breathe in all sizes of particles 24 hours a day.
>
> What is the difference between that and our limited exposure in the
studio?
Ron Roy on thu 14 aug 03
Hey Chris,
Something to remember - we use crushed silica - jagged points on each
crystal - they produce scar tissue in the lungs. Beach and desert sand is
rounded so it is not as dangerous.
Ours is also more of a problem because we live and work in it all the time
- we even take it home with us.
I'm not saysing we will all wind up with silicosis - that depends on how
long we work in it and how much there is in the air. Some of us will
thought.
RR
>This has been niggling at me for years - here goes ....
>
>If breathing silica dust is so dangerous, then do people who live near the
>ocean or a
>sandy beach have a higher rate of lung problems??
>
>Sand is silica .... the wind has to carry even the finest particles all
>the time ... the
>residents breathe in all sizes of particles 24 hours a day.
>
>What is the difference between that and our limited exposure in the studio?
>
>Chris Campbell - in North Carolina - hope somebody has an answer !
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Paul Herman on fri 15 aug 03
Howdy Vince, and all Dust Breathers,
I've been following the whole Toxic thread(s) with interest, and have
had to bite my keyboard to make sure I don't write something brash.
Tastes like plastic augmented with Silica dust.
Yes, that pesky Silica is everywhere. And a good thing it is too,
because it makes up most of the Earth's Crust, where we all live. It's
reassuring to have a thick slab of Granodiorite between me and the fires
of Hell. No doubt, I'll be there soon enough, eh? It is HOT down there
under the crust, more than cone 10! Silica is my friend, and I love the
Earth, but wet mop the studio once in a while.
When you get right down to it, breathing ANY kind of dust will hurt you,
if you do it to excess. Black lung, Brown lung, Miner's Con
(consumption), they are all from breathing excessive dust. The last one
is 'Silicosis'. Are there any Potters out there who have Silicosis?
A thing I've noticed, especially over the last couple of years, is that
fear and hysteria have been selling rather well, havent they? Certain
politicians and appointees have been observed peddling fear, and they
sold a lot to a bunch of fearful people. Remember the "Mad Boxer"? The
black boxes certainly sold well.
So now, when someone starts spewing that hysteria shit at me, the first
thing I ask myself is, "Self, what are they trying to sell you?" Is it a
ionizing air scrubber, a book, or a war?
Well, I AIN'T BUYING FROM THE DEMENTED ONES, and I hope you all don't
either.
Feeling ever so warm and fuzzy about my wet mop,
Paul Herman
Great Basin Pottery
423-725 Scott Road
Doyle, California 96109 US
potter@psln.com
>> Sand is silica .... the wind has to carry even the finest particles all
> the time ... the
>> residents breathe in all sizes of particles 24 hours a day.
>> What is the difference between that and our limited exposure in the
> studio?
>
> Chris -
> There is no difference. You should take every precaution to avoid breathing
> silica dust, but inevitably there is going to be a minute fraction of silica
> dust in the air in your studio, just like there is going to be a minute
> fraction of silica dust in the air when you are at the beach, when you drive
> down a gravel road behind another car, or when you hike through granite sand
> in the High Sierra behind another hiker. You will drive yourself crazy if
> you succumb to extreme toxic scare tactics. The lesson here is not to be
> overly paranoid about such things. Some people (even here on
> Clayart) like to perpetuate extreme toxic scare tactics, but they are
> demented and should be ignored.
>
> Another example - barium carbonate BELONGS in the glaze lab. It can be
> used safely in stable high-fire glazes on functional wares, and it can be
> used in ANY low or high-fire glazes for sculptural work. Strontium
> carbonate cannot do what barium does. It is not an acceptable substitute.
>
> There are lots of other examples. But as I said, the lesson here is to be
> sensible and safe, and never succumb to irrational paranoia about toxicity
> issues. There's nothing to be gained there.
> Best wishes -
> - Vince
Vince Pitelka on fri 15 aug 03
> Sand is silica .... the wind has to carry even the finest particles all
the time ... the
> residents breathe in all sizes of particles 24 hours a day.
> What is the difference between that and our limited exposure in the
studio?
Chris -
There is no difference. You should take every precaution to avoid breathing
silica dust, but inevitably there is going to be a minute fraction of silica
dust in the air in your studio, just like there is going to be a minute
fraction of silica dust in the air when you are at the beach, when you drive
down a gravel road behind another car, or when you hike through granite sand
in the High Sierra behind another hiker. You will drive yourself crazy if
you succumb to extreme toxic scare tactics. The lesson here is not to be
overly paranoid about such things. Some people (even here on
Clayart) like to perpetuate extreme toxic scare tactics, but they are
demented and should be ignored.
Another example - barium carbonate BELONGS in the glaze lab. It can be
used safely in stable high-fire glazes on functional wares, and it can be
used in ANY low or high-fire glazes for sculptural work. Strontium
carbonate cannot do what barium does. It is not an acceptable substitute.
There are lots of other examples. But as I said, the lesson here is to be
sensible and safe, and never succumb to irrational paranoia about toxicity
issues. There's nothing to be gained there.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Office - wpitelka@tntech.edu
615/597-6801 x111, FAX 615/597-6803
http://iweb.tntech.edu/wpitelka/
Norman van der Sluys on sun 17 aug 03
While I agree with much of what you have to say about barium carbonate, I must
comment. Yes, I have seen barium carbonate listed as an ingredient in rat poison,
it has always been listed as an inert ingredient! Also, I don't recall having seen
that small skull and crossbones on any of the barium carbonate I have bought.
Could this be a difference between U.S. and Canadian Law?
Perhaps barium carbonate should be licensed for posession only by those who have
demonstrated knowledge of it's potential for harm, but there are many who think
that the same should apply to firearms. Few of my neighbors would agree with that!
I have used a glaze base with a high amount of barium for two glazes, one a copper
blue-green color and the other a nice matt black. I use the matt black sparingly on
the outside of vessels for the way it reacts with a particular matt white glaze -
nice flashes of purple, etc. On testing, I discovered that strontium produced an
effect that was well within the range of effects I get with the barium. I
switched.
The strontium base with copper was putrid, so now I have two completely different
glazes. I will not give up the barium for that glaze, but will continue to use it
sensibly. I am confident that the use of normal safety precautions such as the use
of a proper mask and good ventilation, good cleanup practices, etc. will minimize
what small risk there might be for me.
Ron Roy wrote:
> Barium Carbonate - like any other toxic material - should only belong to
> those who understand how and when to use it - another point of view.
>
> There is a scull and cross bones on the original bag when you buy it - and
> on the smaller amounts packaged by suppliers - it's the law.
>
> Barium Carb. is an effective rat poison - so don't let your pussy cats
> drink from the glaze bucket - or your children.
>
Norman van der Sluys
Benona Pottery
by the shore of Lake Michigan
iandol on sun 17 aug 03
Dear Paul Herman,=20
You say <me and the fires of Hell. >>=20
Though it may seem a long way of as a destination in terms of Time it's =
a lot closer than we think in terms of space. Could be as close to your =
tootsies at 20 miles. Isn't the temperature increase by something like a =
degree Celsius per hundred feet?
Best regards,
Ivor Lewis. Redhill, South Australia
Ron Roy on sun 17 aug 03
Barium Carbonate - like any other toxic material - should only belong to
those who understand how and when to use it - another point of view.
There is a scull and cross bones on the original bag when you buy it - and
on the smaller amounts packaged by suppliers - it's the law.
Barium Carb. is an effective rat poison - so don't let your pussy cats
drink from the glaze bucket - or your children.
When it's used as a secondary flux in smaller amounts in high fired white
glazes Strontium Carb. is a viable substitute - with the advantage that you
need less and it will help cure crazing.
The particular colour response from Copper and Cobalt in a high Barium
glaze is unique. Just keep in mind - those glazes are not stable and if
used as a liner glaze - will leach barium ions into acidic food - as will
any unstable glaze with Barium in it. Your customers will be annoyed if
your ware changes colour in use - if they find out it is leaching a poison
into their food - they will be furious - no matter what the degree or
danger.
As a side note - while Barium mattes are better with copper and cobalt -
Strontium mattes are better with rutile and iron
If you want to use Barium Carb. as a flux in functional glazes you need to
understand the material and how to make a stable glaze or at least find
some that are stable - by having them lab tested - then there is no
problem.
RR
>Another example - barium carbonate BELONGS in the glaze lab. It can be
>used safely in stable high-fire glazes on functional wares, and it can be
>used in ANY low or high-fire glazes for sculptural work. Strontium
>carbonate cannot do what barium does. It is not an acceptable substitute.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Ron Roy on sun 17 aug 03
It will always be the case - when ignorance is addressed - there will
always be those who say the sky is falling.
Not a good reason to remain in ignorance - never will be.
Some changes are for the better - does not have to be a stressful thing -
some changes should be welcome and reassuring.
RR
>A thing I've noticed, especially over the last couple of years, is that
>fear and hysteria have been selling rather well, havent they? Certain
>politicians and appointees have been observed peddling fear, and they
>sold a lot to a bunch of fearful people. Remember the "Mad Boxer"? The
>black boxes certainly sold well.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
steve harrison on sun 17 aug 03
>
Good call Paul
Steve Harrison
>
> A thing I've noticed, especially over the last couple of years, is that
> fear and hysteria have been selling rather well, havent they?
> Well, I AIN'T BUYING FROM THE DEMENTED ONES, and I hope you all don't
> either.
>
> Feeling ever so warm and fuzzy about my wet mop,
>
Ababi on mon 18 aug 03
Yes
See in my site my S4b glaze
Strontium and cryolite: Lovely turquoise and lovely yellows:
No leaching. Not food surface. All my testes to add silica produced ugly
glazes. In this case it is either (or) nor!
The only damage of not using barium are the barium purple but I manage
somehow with my other 10000 or (1000000) glazes.
Ababi Sharon
Glaze addict
Kibbutz Shoval Israel
ababisha@shoval.org.il
http://members4.clubphoto.com/ababi306910
http://www.matrix2000.co.nz/Matrix%20Demo/Ababi.htm
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Ron Roy
Sent: Sunday, August 17, 2003 7:16 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Silica Dust - silly question for the experts
Barium Carbonate - like any other toxic material - should only belong to
those who understand how and when to use it - another point of view.
There is a scull and cross bones on the original bag when you buy it -
and
on the smaller amounts packaged by suppliers - it's the law.
Barium Carb. is an effective rat poison - so don't let your pussy cats
drink from the glaze bucket - or your children.
When it's used as a secondary flux in smaller amounts in high fired
white
glazes Strontium Carb. is a viable substitute - with the advantage that
you
need less and it will help cure crazing.
The particular colour response from Copper and Cobalt in a high Barium
glaze is unique. Just keep in mind - those glazes are not stable and if
used as a liner glaze - will leach barium ions into acidic food - as
will
any unstable glaze with Barium in it. Your customers will be annoyed if
your ware changes colour in use - if they find out it is leaching a
poison
into their food - they will be furious - no matter what the degree or
danger.
As a side note - while Barium mattes are better with copper and cobalt -
Strontium mattes are better with rutile and iron
If you want to use Barium Carb. as a flux in functional glazes you need
to
understand the material and how to make a stable glaze or at least find
some that are stable - by having them lab tested - then there is no
problem.
RR
>Another example - barium carbonate BELONGS in the glaze lab. It can
be
>used safely in stable high-fire glazes on functional wares, and it can
be
>used in ANY low or high-fire glazes for sculptural work. Strontium
>carbonate cannot do what barium does. It is not an acceptable
substitute.
Ron Roy on tue 19 aug 03
Hi Norman,
I wish all potters were as careful as you are with Barium Carbonate.
I did a google search on "barium carbonate toxicity" - it is kinda long but
here is one of the results.
Toxicity Profiles
Toxicity Summary for BARIUM
NOTE: Although the toxicity values presented in these toxicity profiles
were correct at the time they were produced, these values are subject to
change. Users should always refer to the Toxicity Value Database for the
currect toxicity values.
Prepared by A. A. Francis, M.S., D.A.B.T., and Carol S. Forsyth, Ph.D.,
Chemical Hazard Evaluation Group in the Biomedical and Environmental
Information Analysis Section, Health Sciences Research Division, *.
Prepared for OAK RIDGE RESERVATION ENVIRONMENTAL RESTORATION PROGRAM
*Managed by Martin Marietta Energy Systems, Inc., for the U.S. Department
of Energy under Contract No. DE-AC05-84OR21400
The soluble salts of barium, an alkaline earth metal, are toxic in
mammalian systems. They are absorbed rapidly from the gastrointestinal
tract and are deposited in the muscles, lungs, and bone. Barium is excreted
primarily in the feces.
At low doses, barium acts as a muscle stimulant and at higher doses affects
the nervous system eventually leading to paralysis. Acute and subchronic
oral doses of barium cause vomiting and diarrhea, followed by decreased
heart rate and elevated blood pressure. Higher doses result in cardiac
irregularities, weakness, tremors, anxiety, and dyspnea. A drop in serum
potassium may account for some of the symptoms. Death can occur from
cardiac and respiratory failure. Acute doses around 0.8 grams can be fatal
to humans.
Subchronic and chronic oral or inhalation exposure primarily affects the
cardiovascular system resulting in elevated blood pressure. A
lowest-observed-adverse-effect level (LOAEL) of 0.51 mg barium/kg/day based
on increased blood pressure was observed in chronic oral rat studies (Perry
et al. 1983), whereas human studies identified a no-observed-adverse-effect
level (NOAEL) of 0.21 mg barium/kg/day (Wones et al. 1990, Brenniman and
Levy 1984). The human data were used by the EPA to calculate a chronic and
subchronic oral reference dose (RfD) of 0.07 mg/kg/day (EPA 1995a,b). In
the Wones et al. study, human volunteers were given barium up to 10 mg/L in
drinking water for 10 weeks. No clinically significant effects were
observed. An epidemiological study was conducted by Brenniman and Levy in
which human populations ingesting 2 to 10 mg/L of barium in drinking water
were compared to a population ingesting 0 to 0.2 mg/L. No significant
individual differences were seen; however, a significantly higher mortality
rate from all combined cardiovascular diseases was observed with the higher
barium level in the 65+ age group. The average barium concentration was 7.3
mg/L, which corresponds to a dose of 0.20 mg/kg/day. Confidence in the oral
RfD is rated medium by the EPA.
Subchronic and chronic inhalation exposure of human populations to
barium-containing dust can result in a benign pneumoconiosis called
"baritosis." This condition is often accompanied by an elevated blood
pressure but does not result in a change in pulmonary function. Exposure to
an air concentration of 5.2 mg barium carbonate/m3 for 4 hours/day for 6
months has been reported to result in elevated blood pressure and decreased
body weight gain in rats (Tarasenko et al. 1977). Reproduction and
developmental effects were also observed. Increased fetal mortality was
seen after untreated females were mated with males exposed to 5.2 mg/m3 of
barium carbonate. Similar results were obtained with female rats treated
with 13.4 mg barium carbonate/m3. The NOAEL for developmental effects was
1.15 mg/m3 (equivalent to 0.8 mg barium/m3). An inhalation reference
concentration (RfC) of 0.005 mg/m3 for subchronic and 0.0005 mg/m3 for
chronic exposure was calculated by the EPA based on the NOAEL for
developmental effects (EPA 1995a). These effects have not been
substantiated in humans or other animal systems.
Barium has not been evaluated by the EPA for evidence of human carcinogenic
potential (EPA 1995b).
Retrieve Toxicity Profiles Formal Version
Last Updated 10/07/97
------------------------------------------------------------------------
RAIS Home | Search the RAIS | PRGs | Regulatory Limits | Tox Profiles | Tox
Values | Chemical Factors
Toxicity Metadata | HH Risk Models | Eco Benchmarks | Glossary | Background
For information or technical assistance, please contact Fred Dolislager.
>While I agree with much of what you have to say about barium carbonate, I must
>comment. Yes, I have seen barium carbonate listed as an ingredient in rat
>poison,
>it has always been listed as an inert ingredient! Also, I don't recall
>having seen
>that small skull and crossbones on any of the barium carbonate I have bought.
>Could this be a difference between U.S. and Canadian Law?
>I have used a glaze base with a high amount of barium for two glazes, one
>a copper
>blue-green color and the other a nice matt black. I use the matt black
>sparingly on
>the outside of vessels for the way it reacts with a particular matt white
>glaze -
>nice flashes of purple, etc. On testing, I discovered that strontium
>produced an
>effect that was well within the range of effects I get with the barium. I
>switched.
>
>The strontium base with copper was putrid, so now I have two completely
>different
>glazes. I will not give up the barium for that glaze, but will continue
>to use it
>sensibly. I am confident that the use of normal safety precautions such
>as the use
>of a proper mask and good ventilation, good cleanup practices, etc. will
>minimize
>what small risk there might be for me.
Norman van der Sluys
Benona Pottery
by the shore of Lake Michigan
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Butch Welch on tue 19 aug 03
Question about Ferro Frit 3247, which contains 53 % barium, would you
consider that safe to use in a glaze for functional ware since it is in a
frit?
Regards, Butch Welch
Bwelch1@charter.net
Ababi on wed 20 aug 03
Safe to you unsafe for the users
Ababi
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Butch Welch
Sent: Tuesday, August 19, 2003 11:30 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Silica Dust - silly question for the experts
Question about Ferro Frit 3247, which contains 53 % barium,
.
Ron Roy on wed 20 aug 03
All depends on how well the glaze is formulated to be stable - you would
need to have it tested for barium release and then decide for your self if
it is a potential problem.
Not many potters I know even know how to formulate a stable glaze for starters.
I would recommend not using that frit for liner glazes - there are plenty
of frits with no toxicity concerns.
RR
>Question about Ferro Frit 3247, which contains 53 % barium, would you
>consider that safe to use in a glaze for functional ware since it is in a
>frit?
>
>Regards, Butch Welch
>Bwelch1@charter.net
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
John Hesselberth on wed 20 aug 03
Hi Butch,
A frit is safer for the potter to handle, but it has no effect on the
stability of the final glaze. That depends on the final glaze
composition, the temperature to which it was fired and the colorants
you added. There is no way to know if the final glaze will leach
barium without having it laboratory tested.
Regards,
John
On Tuesday, August 19, 2003, at 05:30 PM, Butch Welch wrote:
> Question about Ferro Frit 3247, which contains 53 % barium, would you
> consider that safe to use in a glaze for functional ware since it is
> in a
> frit?
http://www.frogpondpottery.com
http://www.masteringglazes.com
Louis Katz on wed 20 aug 03
Hi John,
I've read somewhere (Borax handbook?) that proper fritting does has a
positive effect (less soluble) on leaching given the same glaze
composition, probably from more intimate mixing. I'll try to find it.
But I agree with your conclusion.
Louis
On Wednesday, August 20, 2003, at 04:55 AM, John Hesselberth wrote:
> Hi Butch,
>
> A frit is safer for the potter to handle, but it has no effect on the
> stability of the final glaze. That depends on the final glaze
> composition, the temperature to which it was fired and the colorants
> you added. There is no way to know if the final glaze will leach
> barium without having it laboratory tested.
>
> Regards,
>
> John
> On Tuesday, August 19, 2003, at 05:30 PM, Butch Welch wrote:
>
>> Question about Ferro Frit 3247, which contains 53 % barium, would you
>> consider that safe to use in a glaze for functional ware since it is
>> in a
>> frit?
> http://www.frogpondpottery.com
> http://www.masteringglazes.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.
>
Snail Scott on wed 20 aug 03
At 04:30 PM 8/19/03 -0500, you wrote:
>Question about Ferro Frit 3247, which contains 53 % barium, would you
>consider that safe to use in a glaze for functional ware since it is in a
>frit?
Being fritted makes it safer for the maker,
not the end user. It doesn't change the
fired glaze much at all, compared with the
same formula unfritted. Better mixed, maybe,
but a long soak would probably do that, too.
-Snail
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