---greg schmitz
P.S.  For any kind of info having to do with metals, machining,
structure, casting, plating, etc.  there is a multi-volume set called,
as I recall, THE METALS HANDBOOK.  Any good engineering library should
have a set.
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Wall and Jordon. PHOTOGRAPHIC FACTS AND FORMULAS. Boston: American 
Photographic Publishing, 1940. pg 332
To Blacken Aluminum - Clean perfectly free from grease by washing in soda 
solution, wash well, and immerse in:
Ferrous sulphate............	1 part
Arsenious acid .............	1 part
Hydrochloric acid ..........   12 parts
Water ......................   12 parts
When the color is deep enough, dry with fine sawdust, and then
lacquer.  This solution is intensely poisonous.
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> Does anyone know a chemical means for blackening aluminium. 
> 
> I have made some lensboards for my field cameras and need to blacken them. 
> 
> I know I can use paint, but it doesn't seem to last very long, and while 
> anodising is an alternative, the nearest facility is about 300 km away. 
> 
> Any ideas? or should I just get them anodised.
> 
> Peter McDonald.
> Canberra, Australia
> 
> 
> 
> 
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