Re: [Paddlewise] aluminum and salt water (was:blown out footpeg)

Didn't know wether anyone was interested, but:

> >gabriel l romeu
>   You ask
> 
> >Outside of an
> >electrolytic reaction with a disimilar metal, what other corrosive
> >properties is aluminum subjected to in sea water?
> 
>   I'm no "authority" on corrosion, but I assisted another engineer a couple of
> years ago with a sea water corrosion test for the Navy.
>   One reaction (other than the obvious dissimilkar metal contact 'erosion') was
> the corrosion on the aluminum due to its 'impurities'. The aluminum will grow
> spots where the appropriat elements within the alloy will make their own little
> dissimilar metal -- electrolytic action.
>   We were evaluating aluminum and stainless steel junctions. 
> 
>   Jerry

This seems very logical to me.  The 6061 I use is an alloy of aluminum,
magnesium, silicone and a bit of copper I believe.  Probably wise to
lacquer coat my pegs.

> 
> Aluminum alloys have an oxide on their surfaces.This is a rusting effect that
> provents
> the al. from rusting further. Salt in sea water
> attacks and strips this oxide off,allowing further oxidation.
> Painting,anodizing even chemical coating will help slow it down. Al.allot 5083
> is
> a marine alloy designed for its use in sea water.If you can make them out of
> this alloy.
> Hope this helps.
> Frank

Thanks to the good people of the metalworking newsgroup.

-- 
gabriel l romeu
http://members.aol.com/romeug     studio furniture
http://members.aol.com/romeugp    paintings, photos, prints, etc.
http://members.xoom.com/gabrielR  a daily photo journal

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