Walnut shell grit blast media

Heather Galli <heather.galli [at] yale__edu> writes

>We are conducting some experiments in the construction of leaded
>bronze cast bowls employing the lost wax method.  We would like to
>clean the surface of the cast bowls without getting rid of any
>evidence imparted from the mold material. Upon investigation, we
>have found that walnut shell grit might do the trick. Could someone
>please recommend an appropriate grit size for walnut shell grit
>blast media?   Also, a reputable source for purchase would be
>greatly appreciated.

As an member of the local pistol club, I reload all my own
ammunition and regularly clean my spent re-usable brass cartridge
cases  with a case tumbler which uses crushed walnut shells.
I estimate the "grit" size to be approximately 70 (coarse-medium).

The dry walnut shell media is sold by a USA company called Frankfort
Arsenal, any good American gun shop should stock it.

Karl Gillies
Registrar
Southland Museum and Art Gallery
(courier address: Queens Park, Invercargill)
PO Box 1012 Invercargill
New Zealand
+64 3 2199069
Fax: +64 3 2183872


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                  Conservation DistList Instance 19:38
                 Distributed: Monday, February 20, 2006
                       Message Id: cdl-19-38-008
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