On Mon, 08 Apr 2013 18:29:54 -0500, Richard
wrote:

On 4/8/2013 4:06 PM, Ed Huntress wrote:

Snipped - just to show it's technically possible...

Something is strange there. I'd have to dig out my ASM book to check,
but 7075 has low corrosion resistance overall and is not recommended
at all for marine environments (or salty sweat, one would assume).
6061 is somewhere in the middle.


I wondered about that too.

What's the story here?

Ok, from ASM's "Metals Handbook," 9th Edition:

7075 is more corrosion-resistant thant 2024 but worse than any other
wrought alloy.

The zinc is no help, but it's the copper that's the big problem, as it
is with 2024. However, the copper improves resistance to
stress-corrosion cracking.

So in terms of general corrosion, 7075 kind of stinks. 6061 is good
even in marine environments -- although some 5xxxx and 1100 are
better.

--
Ed Huntress