DRB Seattle on tue 5 aug 08
Karin
In books I've seen calcining recommended.=A0 For a friend who did Crystal g=
lazes this was "normal" and anything else "crazy".
Zinc Ox. is Hygropscopic (Maybe Ivor can give a better spelling and definit=
ion) but I think it means "Zinc sucks"(moisture out of the air- even the de=
sert has Humidity)
--- On Mon, 8/4/08, Karin Givon wrote:
From: Karin Givon
Subject: Re: that dratted zinc
To: CLAYART@LSV.CERAMICS.ORG
Date: Monday, August 4, 2008, 8:37 PM
I'm making up some glazes and testing some others, and ran into a
problem that has beleagured me for many years--my zinc! It is nice
and soft and (almost) fluffy when I buy it--at least not in those
little ( and some big) lumps that it forms within a couple of months
of living in my studio. When I lived in Mendorific I thought it was
the damp. Now I live in dry, dry (O SO DRY!) Nevada City and it once
again lumped. Hard to dissolve. Hard to strain. What am I doing
wrong, and what can I do about it? Any wisdom out there? (I live too
far from a ceramic supply place to drop in and buy a half pound
whenever I need it.)
Thanks,
Karin
=0A=0A=0A
Ivor and Olive Lewis on wed 6 aug 08
Dear DRB Seattle,
One Pee to many. .
...Hygroscopic. ....Having a tendency to adsorb water.
Classic example is Magnesium Chloride which will dissolve the adsorbed
water and is the impurity that causes Table Salt caking. The other
classic example is Cobalt chloride which gives a colour change from
pink to blue.
I have no information about Zinc oxide being Hygroscopic. It is
insoluble in Water. But many materials are known to "Cake" if left to
stand for long periods.
Thanks for asking.
Ivor Lewis.
Redhill,
South Australia.
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