George Lendich wrote:

 Andrew and All,
 I've found that single pack epoxy primer to be excllent in all applications.

 I made a motorbike stand and used epoxy primer. I spilled brake fluid
 over the stand top and forgot to clean it up - well it sure took off the
 surface paint, but didn't even look like hurting the primer. I swear by the
 stuff, everything get a coat of this stuff before painting now.

 Although I've never used it on aircraft aluminium, I'm wondering how
 it goes on that - anyone have info or experience on that !!?

 > George (down under)

James Russell wrote:

Hi George:

        The way I usually do it:

        1) Clean w/ MEK, acetone, etc. to degrease.
        2) Etch w/ "phosphoric acid": Alumiprep or equivalent 2-3 mins.
        3) Rinse clean w/ water
        4) Alodine w/ Alodine 33 or equivalent until a pleasing light gold to
            light brown color appears.
        5) Rinse clean w/ water.
        6) Air dry and don't touch the surface.
        7) Prime and topcoat as usual.

        Tips:
        You can get the Alumiprep and Alodine 33 at any airport or
        paint supply house. Wear gloves and don't dump this stuff down
        the drain as the alodine has a heavy metal ( chromium? ) in it.

<Rant>
Bare aluminum corrodes really, really fast - even the Alclad type.
Etch, alodine,
and prime everything - shoot your rivets wet w/ primer - seal all
faying surfaces,
  seams, etc. w/ polysulfide sealer.  Yes, it's messy and a pain - but
you'll sleep
better knowing that the metal worms will attack someone else's pride 'n joy.
Plus, someone looking in an access hole will be very impressed that
you cared...
</Rant>

Just my $ .02...

Regards,
James

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