Curt
As I understand, many primers are UV sensitive and that is why you
want to top coat them. When you see a paint job that is popping the paint
down to the primer, that usually means not enough top coat was applied and
the primer is reacting to the UV light.
I don't have any spec sheet to tell me if Self-etching or Epoxy
primers are UV sensitive or how long they will hold up if not top coated.
All I can say is that I have a number of parts coated in just these primers
and they show no signs of deterioration, but those parts are not exposed to
direct sunlight either.
All paints have a cure time and a time allowed for top coat or
re-coat so the layers will bond correctly. When you exceed that time limit
you just need to scuff the surface and apply the next coat. I prefer to
allow enough time to get the whole project painted in one time period, it
just seems easier with todays paints.
Ron Fraser
-----Original Message-----
From: owner-tigers@Autox.Team.Net [mailto:owner-tigers@Autox.Team.Net] On
Behalf Of Curt
Sent: Friday, February 04, 2005 6:07 PM
To: Tiger List
Subject: Re: Expansion tank
There are plenty of rattle can self-etching primers out there. Having about
completed building an aluminum airplane I hae done a lot of priming. I
typically did the big parts e.g. wing skins, with a spray gun, and the
smaller parts or touch up with a rattle can. Any good automobile paint store
or aircraft supply place e.g. Aircraft Spruce, will have the primers.
In the aviation world at least, and from all the technical data I have read
in my project, you do not want to just do primer. They are not made for
leaving exposed. It may be more of an issue on airplanes and aluminum, but
they state you should cover the primer with a compatible top coat in fairly
short order, or you will have to redo it (or live with the corrosion issues
later). Primers in and of themselves do not offer corrosion resistance.
Having said that, many of us primed the insides of assemblies and never
painted over it. But I also acid etched it first and alodined it as well
(unless I was using just the rattle can self etching primer in which case
that was all I did).
Sold the plane- too much work : ) Back to tigers
Curt Hoffman
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