primer

[bobp]

.
I can't stand it !!

Doesn't ANYBODY <RTFM> anymore ???!!! (OR the Archives !!??)

AFAIK, "Real" Zinc Chromate has been ILLEGAL, and NOT for sale
in North America for OVER 20 years !! Do not use ANYTHING in 'spray cans' -
it is almost always some kind of lacquer -- and it WILL eventually break down
into tiny flakes ... which do terrible things to your lungs !! (Have seen this often !)

The ORIGINAL recommendation was to use PolyFiber EP-420/430
2 part Epoxy Primer - brushed on between joining parts, and joined WET -
to fill any gaps, preventing capillary action drawing in water, AND providing
a bit of adhesion to make the structure stronger. It was also recommended
that the tips of ALL rivets be dipped in this Epoxy before inserting & pulling WET !
This helped seal around the rivet, and was drawn up around the mandrel, to
seal the stem. Do not dip too much, or the Epoxy will come up the mandrel &
glue the jaws of your rivet gun !! :-( (Don't ask ... ;-) )

Way back in the '70's, when Dick Schreder was bulding the HP series
of metal gliders, he tried lots of different things, and the Polyfiber EP420/430
was the best. A couple of years later, both Boeing and De-Havilland engineers
tested it in chambers with humidity & vibration inputs, using strain guages -
again, PolyFiber EP-420/430 was shown to be THE best choice for corrosion
prevention and bonding !! You can order it from Aircraft Spruce - and others ...

WHY try to re-invent the wheel ???!!!

ALSO - DO NOT put ANY primer in the fuel tank area, inside, or
on joints -- it will interfere with the ProSeal bonding - and you WILL have leaks !!

**/End of RANT /** (Have I offended everybody yet ?? :-) )