[meteorite-list] water glass

From: Zelimir Gabelica <Z.Gabelica_at_meteoritecentral.com>
Date: Thu Apr 22 10:27:50 2004
Message-ID: <1.5.4.32.20031118172708.008a33fc_at_pop.univ-mulhouse.fr>

John, Tom, List,

In Europe, "Water Glass" is some kind of old trade denomination of a
commercial solution of sodium silicate, a clear liquid defined by its molar
(or weight) Na2O/SiO2/H2O ratio that is variable, depending on how much of
silica (acidic behavior) was neutralized by how much NaOH (base)=20
(in other words or for non chemists, sodium silicate, a salt, results from a
(partial) neutralization of SiO2 by NaOH in water).
=20
Such a solution (commercially sold for very cheap) exhibits a relatively
strong basic character (pH close to 12 or so) especially of we deal with an
excess of NaOH versus silica. It can therefore well behave similarly to NaOH
or any other basic compound (such as Na carbonates), in etching irons, if
used in an appropriate way, such as the one described by Steve Schoner in
many early posts.

It is to be noted that the Water Glass layer that is deposited onto the
surface of the meteorite, if not removed by thorough rinsing, would dry onto
this surface and eventually polymerize with time (into complex Na
polysilicates) and, who knows, protect to some extent the so-etched specimen=
 ?

Hope this helps but I'll be glad to learn more as well. Steve ?

Best wishes,

Zelimir
--------
At 08:30 18/11/03 -0700, you wrote:
>Are you perhaps referring to "water glass" - a product that was used to=20
>coat eggs to extend preservation?
>
>John
>
>At 03:23 PM 11/17/03 -0700, Tom aka James Knudson wrote:
>>Hello everyone, Has anyone ever tried (or even heard of ) Liquid Glass on=
=20
>>a meteorite slice?
>>Thanks, Tom
******************************************************
Prof. Zelimir Gabelica
Groupe S=E9curit=E9 et Ecologie Chimiques (GSEC) - ENSCMu
3, rue A. Werner
F-68093 MULHOUSE Cedex, FRANCE
Tel: +33 (0)3 89 33 68 94
FAX: +33 (0)3 89 33 68 15
e-Mail: Z.Gabelica_at_uha.fr
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Received on Tue 18 Nov 2003 12:27:08 PM PST