Wade Blocker on mon 12 mar 01
Dear Clayarters,
Unfortunately I do not have an E-mail address for all of you,and therefore
I cannot thank you individually for your prompt replies. Jim,Fabienne
thank you for the information and advice re the amount of strontium as a
substitute for barium in a glaze. Mia in ABQ
Wade Blocker on mon 12 mar 01
Dear Clayarters,
I am about to mix a glaze that contains a fair quantity of barium.
Cannot find the conversion from Barium to the use of strontium carbonate
instead. Would someone please let me know the anwer to this. Mia in ABQ
Jim V Brooks on mon 12 mar 01
I have replaced all the barium in my glazes with strontium carb. I use
strontium at 75% of the barium required.. SO, your recipes will no longer
total 100%. For example.. a 100 grm Barium would reduce to 75% or 75 grms
of Strontium.. Jim in Denton.
Fabienne Micheline Cassman on mon 12 mar 01
Hi,
You use 3/4 ( or 75%) the amount of barium carb. So, if the recipe calls
for 10 unites of bariums, you will need 7.5 units of strontium carb.
Fabienne
>Cannot find the conversion from Barium to the use of strontium carbonate
>instead. Would someone please let me know the anwer to this. Mia in ABQ
--
Milky Way Ceramics http://www.milkywayceramics.com/
Yes, I have learned from my mistakes...
I can reproduce them exactly.
Stephen Grimmer on tue 13 mar 01
Mary Beth,
Why the EPK? There is neither silica nor alumina in barium carbonate to
replace, nor does barium carb float a glaze. Can you elaborate? Substituting
0.75 stontium for 1 barium will get you a direct molecule for molecule
replacement. Why the range of 0.66 to 0.75?
Steve
> From: MaryBeth Bishop
> Subject: Re: strontium carb
>
> Dear Mia,
> The directions I use for Barium replacement are:
> Replace Barium with .66 to .75 Strontium Carb.
> Add EPK for the balance.
> Mary Beth Bishop in NC
MaryBeth Bishop on tue 13 mar 01
Dear Mia,
The directions I use for Barium replacement are:
Replace Barium with .66 to .75 Strontium Carb.
Add EPK for the balance.
For example if your recipe calls for 10 grams of Barium you can replace this
with
7 grams Strontium Carb. and 3 grams of EPK
This has worked for me but I have never used a recipe which had great
quantities of Barium in it originally.
Mary Beth Bishop in NC
The garden calls/ the studio calls and my mailbox is full of posts.
If this is the worst problem I have, I am one lucky woman.
MaryBeth Bishop on wed 14 mar 01
Steve,
I don't know. I was glad the question came up as I thought someone else
might know. This is just what I was told to do and I do it and it works. It
may have more to do with glaze consistency/adherence than anything else. I
have never seen this written anywhere. Always the substitution is a direct
2/3 to 3/4 Strontium for Barium. The EPK doesn't hurt anything apparently.
Does it help. I don't know. I plead stupid.
Mary Beth
Lili Krakowski on wed 14 mar 01
I sart with 1-1 and go up if necessary. TEST. TEST ON TILE on an old
shelf, or on a wafer of clay. I have never understood eutectics, really,
I sigh and call them miracles. And tehy do happen.
Lili Krakowski
MaryBeth Bishop on thu 15 mar 01
I suspect that whoever originally did the EPK addition which I learned was
doing it just to make the numbers come out right. It really doesn't effect
the glaze that I can see. I know this is enough to make glaze gurus crazy.
Sloppy thinking. I'm sorry.
Mary Beth
Jim V Brooks on thu 15 mar 01
Stephen, i suspect that she adds EPK to help keep the mix in suspension.
The clay could do this.
Tom Buck on fri 16 mar 01
Ms. Bishop:
You won't upset us so-called glaze gurus by adding another
ingredient or increasing one already on the list. It is reasonable for you
to jiggle any recipe to your heart's desire; in fact, one should always
adapt recipes to their claybody. In the case of the BaCO3 to SrCO3
conversion, IF you wanted to maintain the batch as cited, then do not add
or otherwise change the recipe even when you decrease the batch total
because SrCO3 produces less WEIGHT than BaCO3. In molecular terms the
glaze will have the same number of molecules. But if you increase one
other material (or add one), the the molar proportions are changed,
perhaps for the good, perhaps for the bad. Only a test will tell.
bye. peace. tom b.
Tom Buck ) tel: 905-389-2339
(westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street,
Hamilton ON L8T 3E1 Canada
Heather Botelle on sun 18 mar 01
Speaking of Strontium. =A0I just came from a workshop where the presenter=20
informed us that Strontium was just as bad as Barium and should be avoided i=
n=20
all food ware. =A0Is this true? =A0Does anyone out there have any=20
details/research?
Thanks,
Heather in CT where the birds are finally singing each morning
Edouard Bastarache on sun 18 mar 01
Strontium carbonate
The greatest danger to humans is from artificial isotopes 89Sr and 90
Sr produced in nuclear reactions ; fallout of 90 Sr mainly from atmospher=
ic
nuclear explosions (and power-plant reactor accidents) has caused great
concern.These isotopes are deposited in bones, acting as a source of
internal radiation.The 90 Sr has a half-life of 28 years and emits beta
particles that damage the blood forming cells in the bone marrow.
Obviously, as can be seen, this is not the case of strontium carbonate
Edouard Bastarache M.D.(Occupational & Environmental Medicine)
Author of =AB Substitutions for raw ceramic materials =BB
edouardb@sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/~edouardb/
Tracy
Quebec
Canada
Reference :
Occupational Medicine, Carl Zenz, last edition.
Ron Roy on sun 18 mar 01
Rubbish, but I am not surprised.
Perhaps you would find it in your hart to send me their name and I will
endeavor to inform them. Perhaps this might be a way to get rid of some of
the misinformation so rampant.
What is so bad about the phrase " I have heard but don't know for sure"
that so many cannot use it?
Thanks for posting this Heather - you do us all a service.
RR
>Speaking of Strontium. I just came from a workshop where the presenter
>informed us that Strontium was just as bad as Barium and should be avoided in
>all food ware. Is this true? Does anyone out there have any
>details/research?
>
>Thanks,
>Heather in CT where the birds are finally singing each morning
Ron Roy
RR# 4
15084 Little Lake Rd..
Brighton,
Ontario, Canada
KOK 1H0
Residence 613-475-9544
Studio 613-475-3715
Fax 613-475-3513
John Hesselberth on sun 18 mar 01
Hi Heather,
I would like to know your presenters source. Strontium is more like calciu=
m
on the toxicity scale. Next time you hear a statement like that ask the
source. My source is Sax "Dangerous Properties of Industrial Materials",
Sixth edition where on page 2471 it says "The strontium ion has a LOW order
of toxicity. It is chemically and biologically similar to calcium...."
Regards, John
"The life so short, the craft so long to learn." Chaucer's translation of
Hippocrates, 5th cent. B.C.
>=20
> Speaking of Strontium. =A0I just came from a workshop where the presenter
> informed us that Strontium was just as bad as Barium and should be avoide=
d in
> all food ware. =A0Is this true? =A0Does anyone out there have any
> details/research?
Ceramic Design Group on sun 18 mar 01
on 3/18/01 12:06 PM, John Hesselberth at john@FROGPONDPOTTERY.COM wrote:
> Hi Heather,
>
> I would like to know your presenters source. Strontium is more like calciu=
> m
> on the toxicity scale. Next time you hear a statement like that ask the
> source. My source is Sax "Dangerous Properties of Industrial Materials",
> Sixth edition where on page 2471 it says "The strontium ion has a LOW order
> of toxicity. It is chemically and biologically similar to calcium...."
Ron Roy wrote:
>perhaps you would find it in your hart to send me their name and I will
>endeavor to inform them. Perhaps this might be a way to get rid of some of
>the misinformation so rampant.
>What is so bad about the phrase " I have heard but don't know for sure"
>that so many cannot use it?
>Thanks for posting this Heather - you do us all a service.
Fusion Frit F-38 is a strontium frit that we use between cone 4-6 and should
solve some of these issues.
Jonathan
--
Jonathan Kaplan
CERAMIC DESIGN GROUP
PO Box 775112
Steamboat Springs, CO 80577
(970) 879-9139
Janet Kaiser on sun 18 mar 01
I presume the person who advised against using
Strontium in glazes, either mistook it for or confused
it with Strontium-90, the radioactive isotope found in
nuclear fall-out and natural sources, which
concentrates in bones and teeth when ingested. It is
one of those unfortunate mistakes which lead to
mis-information and panic. It is unhelpful and an
indication that the tutor needs to do some serious
learning before repeating such a basic mistake.
BTW Strontium is known as Strontian in Scotland. I
never knew why.
We had high levels of Strontium-90 in this area, even
before they built two nuclear power stations within a
fifty mile radius. It was officially considered a part
of the natural background radiation from the granite
bedrock, but some have their doubts.
Janet Kaiser
The Chapel of Art . Capel Celfyddyd
HOME OF THE INTERNATIONAL POTTERS' PATH
Criccieth LL52 0EA, GB-Wales Tel: (01766) 523570
E-mail: postbox@the-coa.org.uk
WEBSITE: http://www.the-coa.org.uk
Tom Buck on mon 19 mar 01
Good yarn, Snail, thanks.
There are many people who still fear there is Sr-90 in their milk,
supposedly from fallout of a-bomb tests over 40 years ago. But with its
short "half-life" most bomb-made Sr-90 has since changed to some other
non-radioactive atomic form.
the strontium carbonate supplied to us potters comes from a
mineral deposit somewhere in the world. The deposit is usually "celestite"
or strontium sulfate which is later changed to the carbonate by chemical
processing. Since such an orebody has been sitting there for eons, and any
Sr-90 has long gone. and potters can put aside another worry.
bye peace. tom b.
Tom Buck ) tel: 905-389-2339
(westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street,
Hamilton ON L8T 3E1 Canada
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