I can formulate glazes. I was hesitant to use Magnesium because I cannot
even image the volume I would need for the equivalent. Dolomite does not
work in the glazes that iis used because the calcium to magnesium ratio
doesn't work. One of the glazes is Randy's Red (ours is Toby's but very
similar).

Toby's Red ^6
32 gerstly
30 flint
20 kona f4
14 talc
5 epk
15.15 RIO

roughly goes to
32 gerstly
30 flint
20 kona f4
8 magnesium carb
15.15 RIO

When this gets upped to 10000grams that is 800 grams of Magnesium Carb....
That strikes me as a huge volume but I may be remembering wrong.

If you think this is worth the try, I will mix up a batch. Thanks, Donna


If you think I can use magnesium to replace the talc, I will work with that.
"Bob Eld" wrote in message
et...

"DKat" wrote in message
...
The writing on the wall is that the University is not going to allow us
to
use Talc either in our glazes or our clays (how in the world you are
supposed to find that out given the mix we have that has come and gone
and
the recycling done...).

Our best glazes use Talc. What in the world can you do to substitute it
especially given that I have used it to keep glazes from crazing and it
is
the only thing that worked.

Donna


Talc adds magnesium to glazes and is used as a flux in some low fire clay
bodies to lower the maturing temperature and extend the firing range. It
is
primarily used in white hobby and school type modeling clays. I'm not sure
what would substitute for it in a clay body, perhaps a frit or other
prepared fluxing agent. Or, perhaps dolomite and silica could serve this
purpose in a body.

Talc is magnesium silicate and provides both magnesium oxide and silica to
a
glaze. Magnesium can be gotten fom dolomite which is a calcium, magnesium
carbonate or from chemical magnesium carbonate.

If substituting dolomite for talc, up the amount of silica in a recipe
and
decrease the amout calcium carbonate, whiting, until the same equivalents
are in the recipe as before.

If substituting magnesium carbonate up the silica, but don't do anything
to
the calcium.

If you know how to formulate glazes, this should be trivial. If you don't
I
would be more than happy to propose an adjuted recipe for you to try.

Just post here or e-mail a favorite talc, glaze recipe and I'll take a
stab
at modifying it for you to try. It should act in every way the same as the
original recipe because all of the elements will be the same, only from
different sources.

My e-mail address is montassocatyahoodotcom Please fix the at and dot.