On Tue, 9 Aug 2016 06:37:42 -0400, "Jim Wilkins"
wrote:

wrote in message
.. .
...
All of the aluminum on my plane is 6061T6 - rivetted.
All flight surfaces and flight structures.

Aluminum boat trailers are routinely welded.

What's the difference?
--jsw

The boat trailer is probably not made from 6061 aluminum :-)
--
cheers,

John B.