[VAC] Corrosion/construction

["Richard McFarland" <estatewagons@xxxxxxxxxxxxxxxx>]

Arlen - thanks for the NASA website address - very interesting.

For years I owned a twin diesel sportfishing boat built in the '30's.
During my ownership I performed a major renovation of the hull of the
boat...($$$)... and it hopefully will live on for many more decades.  I
learned a great deal about (and was continually fascinated by) the many
levels of corrosion - in particular - the habits of individual materials and
the change of those habits in relation to the pairing of similar vs.
dissimilar materials.

I have one question to toss out - and hopefully it won't be taken as a "term
paper" length one...but simply one that seeks a variety of  input.

I've not yet had a chance to open up an Airstream (or similar construction)
trailer - so I am curious what is to be found on and around the mating
surfaces - where the aluminum shell meets the floor/frame area?  Over the
years - has there been an attempt to coat/protect or otherwise minimalize
the potential for corrosion at this joint?

We read so much about soft/rotten floors - particularly around the
perimeter - most often due to the water leaks of one type or another.  I
have to assume that once the wood gets wet and starts to rot - it also helps
to act as a transfer of the corrosion process between (as a result of)
dissimilar metals.  In my search for an Airstream - I've seen a few that had
perforated/corroded  exterior aluminum adjacent to the floor joint. At the
time  - I assumed that the aluminum was worn due to road use/winter use
etc...but I now see where it was probably a secondary result of interior
damage.  I recently looked at an Argosy in my hometown - it had a history of
use in Baja California - and I noted that the front lower area was rusted
through - being that it's an Argosy - I assumed that it must have been due
to the trailer's extensive use in an area near salt water and salt air.  I
now wonder though if it was more likely a result of dissimilar metals in
conjunction with an area (joint) that is known for getting wet (due to
leaks).  Is the superstructure/framework of an Argosy all steel - or is
there a mixture of steel and aluminum in there?

Just curious!
Thanks for a great website.

RL McFarland
'36 Mystery
'41 Kozy
'51 Custom Tent
'77 Mercury Colony Park/'01 Tundra