Re: [VACList] Re: VACList - Laying aluminum panel over damaged panel

["T Meeker" <tmeeker@xxxxxxxxxxxxxxx>]

Scott,

OK -- just for arguments sake
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The corrosion issue is 'solved' by applying a sealer between the sheets of
aluminum where they would be fastened at least.  There is sealer on the
Airstreams under the skin and between the stringers and ribs, just like
aircraft is made.

Or, if there is no wet sealer used like is needed for dissimilar metals
there is at least an epoxy primer applied to *both* contact surfaces which
would suffice for a dry area.  But the outside skin is not a dry area.  It
is this layer of either sealant or primer that keeps the metal from actually
touching one another.

Airstreams would usually leak at seams or rivets if they leak at all from
what I know.  Or, if the exterior skin is punctured that would of course
also be a source of a leak.

The fiberglass insulation between the inner and outer skins is applied just
like it is in the construction of a house -- helps keep out heat and cold.
The fiberglass insulation is just another moisture barrier -- these panels
inside and out are not sealed pressure chambers.  If they were they'd be
totally sealed and an inert gas that wouldn't hold heat -- like nitrogen for
instance -- would be there to take the place of ambient air.

If the fiberglass insulation get wet it's useless.  Wet insulation will not
stop the temps from rising or falling and that's yet another reason to stop
moisture in the first place with very good, solid, leak-proof construction.
When Airstream built these trailers they were designed to stay dry.  Yes,
they might leak eventually at a few loose rivets due to torsion of the whole
trailer body but they weren't built with leaks down the road in mind.  In
fact, the strength of the Airstream seeks to inhibit leaks from the very
beginning with their excellent construction.

Covering damaged panels with a solid sheet is still not a great idea in my
book.  Yes, it may be cost effective for whoever is paying the bill but it's
still not the better way to go as far as the correct repair is concerned.

Let me ask you to think about this -- what is being done with all those open
holes left in the skin underneath the covering panel?  Are they all plugged?
How do you know??  Are they plugged *and* sealed?  How would you ever know??

What if you do get a leak from a new blind rivet -- where do you go from
there?  How the heck would you ever find out *which* rivet is leaking??
After all, there are hundreds of old drilled holes that might not get filled
again or sealed for that matter aren't there?  And by sealed I mean a plug
sealing the hole like the original fastener did at best or sealing it with
sealer at least.  But how would you ever know??

I hate to chase leaks -- and trying to chase down a leaking rivet
'somewhere' on that side with the new skin panel laid over the old would be
a nightmare.  You'd never find it -- you'd have to re-seal in one way or
another *all* the new fasteners at least.  Or would you?  Perhaps it would
just be a leak on that side but how would you know if it was from the double
skin repair or elsewhere?  How would you ever know??  Can you imagine having
to seal an entire half of your Airstream because there is a leak 'somewhere'
but you don't know exactly where??

At least if you had to remove the inner skin for whatever reason our you
could take a peek between the inner and outer skin you might be able to find
the source of a leak.  But it you have a sandwich on one side of the ribs
and stringers finding the exact place to stop that leak would be impossible.
Just impossible!

The people who do the repair would gladly take the unit back to chase down a
leak I'm sure.  But who could afford that type of hourly charge??  Surely a
job like that would cost way more than just removing the old damaged skin
and replacing it with a new piece.  That is the only correct way to do this
type of repair, honestly it is.

Tom