Dave Finkelnburg on tue 10 oct 00
Reading Hal McWhinnie's excellent glaze recipes again reminded me that I
have a personal dislike for manganese dioxide in glazes, and no great
fondness for copper where it can be avoided. The MnO2 is a fume hazard to
the potter during firing of the kiln, the copper a leaching hazard to the
user if applied on food surfaces.
I strongly recommend that before settling on oxides to produce your
favorite black, you do some testing of cobalt and iron. Around 1% cobalt
carbonate, 9% iron will give a pretty black glaze. Add 1% chrome and it's
definitely black.
I'm not saying this is superior, just that it is a different way to get
to black, which may help avoid certain problems.
Good glazing!
Dave Finkelnburg
Cindy Strnad on tue 10 oct 00
Speaking of manganese, I have a question.
Our local water is pretty high in manganese. Is this dangerous? I drink RO
water--does the reverse osmosis process remove manganese--or does it matter?
As far as I can tell, there aren't any standards. At least not around here.
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
earthenv@gwtc.net
http://www.earthenvesselssd.com
pedresel on wed 11 oct 00
Reverse osmosis should remove the manganese if the unit works properly.
My personal opinion is that the main problem with manganese in drinking
water is aesthetic, not health related. I don't have a professional
opinion on this. Of course you could go ahead and test the water after
your treatment system.
-- Evan in W. Richland WA who gets a warm feeling inside from having the
winter's hay stacked and ready to feed to the horses. Besides the
outdoor cat, Lucy, likes to have a cozy spot up high to watch the world.
Cindy Strnad wrote:
>
> Speaking of manganese, I have a question.
>
> Our local water is pretty high in manganese. Is this dangerous? I drink RO
> water--does the reverse osmosis process remove manganese--or does it matter?
> As far as I can tell, there aren't any standards. At least not around here.
>
> Cindy Strnad
> Earthen Vessels Pottery
> RR 1, Box 51
> Custer, SD 57730
> USA
> earthenv@gwtc.net
> http://www.earthenvesselssd.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.
Edouard Bastarache on wed 11 oct 00
Ave Cindi,
The daily diet intake averages between 3 to 7 mg.
Manganese is an essential mineral for humans and animals. It is necessary
for
normal bone formation. It has been estimated that a normal 70-kg man has =
a
total of 12mg to 20 mg in his body.
The biological half-life of manganese is approximately 30 hours.
Quebec=92s standard for drinking water is 0.05 mg/liter expressed as tota=
l
manganese.
It is at this level not for medical reasons, but because it dirties fabri=
cs
and water pipes,
it also gives a bad taste to drinking water.
Reverse osmosis is a good aparatus to remove manganese from drinking wate=
r.
Later,
Edouard Bastarache
Dans / In "La Belle Province"
edouardb@sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/~edouardb/
-----Message d'origine-----
De : Cindy Strnad
=C0 : CLAYART@LSV.CERAMICS.ORG
Date : 10 octobre, 2000 22:08
Objet : Re: Black without manganese
>Speaking of manganese, I have a question.
>
>Our local water is pretty high in manganese. Is this dangerous? I drink =
RO
>water--does the reverse osmosis process remove manganese--or does it
matter?
>As far as I can tell, there aren't any standards. At least not around he=
re.
>
>Cindy Strnad
>Earthen Vessels Pottery
>RR 1, Box 51
>Custer, SD 57730
>USA
>earthenv@gwtc.net
>http://www.earthenvesselssd.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.
| |
|
