Look into using bismuth for shielding. PeptoBismal is Bismuth subnitrate 
so you can eat the stuff. It is dense (9.87gm/cc, vs 11.35 for lead) and 
very easy to cast as it has a quite low melting point. Easy to machine 
too. It is used in shotgun shells in places where lead has become 
unacceptable and in fact that is an easy cheep way to get an evaluation 
sample (just don't set the damn thing off) (or for just a little bit 
email me and I'll mail you some)
-- 

Looking forward,
Al Shinn


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