will edwards on wed 30 may 01
Hello,
I see some things regarding barium and other compounds that are gaining g=
round
again. The worst part I find in my research is how much of our toxic prob=
lems
are due to manufacturing and the by-products from it. We as an industrial=
ized
country among others have subjected ourselves to more toxins through othe=
r
factors much worse than many of the ones we face when we are formulating =
if we
use common horse sense along with our respirators and latex gloves. No I =
am
not covering the other aspects such as burn-off and emissions and all bec=
ause
that has been more than handled many times over.
I do advocate exchanging as often as possible the lessor of any two nasti=
es. I
don't particularly care for the term evil! (Everthing has its place or it=
wouldn't exist!)
There's one way and one way only to know what is what and that is to lab =
test
for the compound after it has been fired to whatever range of heat you ch=
oose
to work at, reduction or oxidation. The toxicity review below must be rea=
d
carefully and put into perspective but it is only one of many ways "WE" c=
an
learn to use and enjoy the materials at hand. Can barium be replaced? I t=
hink
we could see if the subbing out with its sister Strontium on a mole/mole =
level
can work by re-checking the alkylines and basic structure of the glaze on=
ce
more after doing the substituting. Calcium, strontium and barium are all =
part
of this group. If you sub things out just on a one to one level you move =
the
arrangement of other materials around and need to take that into accoutin=
g as
well. If you reduce the Strontium to match the weight on a molecular leve=
l you
certainly have changed the mix of the glaze. In the test glaze I played w=
ith I
seen where the change was mainly in the calcium area. That was/is my vers=
ion
while toying around with the numbers. The realtionship in other glazes ma=
y not
be the same and thus silica and other materials might need adjustments. (=
I
done another one to be sure and the Si:Al wasn't the issue but once more =
the
calcium was changed along with others) Look at the alkylines and the glaz=
e as
it stands with barium, use your software to make as close a match as poss=
ible
and re-adjust the remaining earth alkylines that are forced out of balanc=
e
when you subbed the original. Fire a test tile or two and see what it doe=
s? I
would hazard a guess and say make-up the balance with calcium since the
replacement is around .75 to 1.00 strontium to barium? Not looking that u=
p
right now! Its a little like trying to replace GB on a one to one basis. =
It
ain't going to always work!
http://www.epa.gov/IRIS/toxreviews/0010-tr.pdf
William Edwards
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