Air abrasion using baking soda

In Conservation DistList Instance: 18:51 Tuesday, April 26, 2005
Gordon A. Lewis <gal [at] art-conservation__org> writes

>I recently saw a demonstration of baking soda as an abrasive to
>remove many different accretions; it seemed interesting. The
>demonstrators told me it is in use in dentistry and other arenas.
>According to their literature, baking soda has a MOHS of 2.5 and can
>be used in dry or wet applications. Has anyone used it; have any
>experience; knowledge?

I regularly use baking soda for airbrading palaeontological material
as it is considerably less abrasive than alumina or carborundum
powder.  It effectively (if slowly) removes pyritic accretions and
if used at the correct pressure is useful for cleaning away surplus
or adhering matrices from fossil specimens without 'overcleaning' or
abrading the specimens themselves.  There are various grades of
powder available.

    **** Moderator's comments: My apologies for the delay in posting
    a response, caused by a clerical error on my part.

Simon Moore, MIScT, FLS, AMUKIC,ACR,
Conservator of Natural Sciences.
Hampshire County Council
Recreation and Heritage Department,
Museums and Archives Service,
+44 1962 826737


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                  Conservation DistList Instance 19:3
                  Distributed: Thursday, June 23, 2005
                        Message Id: cdl-19-3-003
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