Dave and others
Polyfiber's website doesn't say a word about Smoothprime - it seems that
it isn't sold any more (?). I am looking for an alternative, that can be
rolled on and has a record of succes (UV-filtering and well bondig to
its base and the final paint), but have no idea where to find it. This
is strange - composite aircrafts are flying since decades, but this
primer-UV-blocker-thing seems to be either a miracle or a first class
secret. I am sure there are some experts out there and still hope they
will share their knowledge.
Alfred
Alfred Buess
Laenggasse 81, CH-3052 Zollikofen, Switzerland
E-Mail: ykibuess@bluewin.ch
Europa XS #097, Monowheel, Foam shortwing, Rotax 912S, Airmaster 332 CS
Bonding the windows into the door frames
-----Ursprngliche Nachricht-----
Von: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] Im Auftrag von
n3eu@comcast.net
Gesendet: Samstag, 10. April 2004 16:04
An: europa-list@matronics.com
Betreff: Re: Europa-List: Repainting the mini U2
rlborger wrote:
>
> The UV protection is a component of the paint that blocks
> UV light preventing it from reaching the composite surface. According
> to Bob Setzer and my EAA Tech Advisor, Sonny Logan, this is extremely
> > important. UV will degrade the epoxy over time resulting in
> significant loss of strength of the composite structure.
The min. qualifications for EAA Tech Counselor is having built one
airplane, or commonly an A&P who need know nothing about fiberglass.
Arguably a viewpoint of people who should know is from System III Resins
(market: FG boat owners and builders) is their "The Epoxy Book." The
say there are even clear coatings you can buy to use as the sole coating
over FG which have requisite chemical UV blocking. Else, you can depend
upon the opacity of the primer and topcoat. When latter begins to break
down, maybe even 10-15 years, they say you best remove and recoat.
Their water-based 2-part epoxy primer (not as chalky and more opaque
than Smooth Prime per my sampling ) does not claim to be a special UV
blocker, and they freely discuss other primers for your boat if you
want. Skipping past the part about problems below the water line, they
say you can otherwise use about any primer, with the only possible
problem of chemical reaction with unreacted amines in the resin.
Doubtfully any factor on Europa's sandwich components, and we're careful
on mix ratios for the other stuff.
Can't insist above is definitive either, but at least there's not one
instance of even UV-suspected structural failure in the U.S. accident
database, including gliders back to year one of the data, 1962, just
failures for reasons like builder error in layup or AAL Flight 587.
Reg,
Fred F.
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