Mailing List lml@lancaironline.net Message #7692
From: J. N. Cameron <toucan@The-I.net>
Subject: Water-based paint system
Date: Thu, 23 Nov 2000 10:56:59 -0600
To: Lancair List <lancair.list@olsusa.com>
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    The prospect of having no toxic solvents and water cleanup seemed too
attractive to pass up, so I've been painting my ES as I go along the the UV
Smooth Prime and Top Gloss system.  For those who are wondering, here are my
impressions so far:

    UV Smooth Prime:  Yes, it's easy to apply, and easy to sand.  You can
recoat after a couple of hours.  And yes, cleanup is easy.  That's about the
extent of what I have good to say about it.  I've been rolling three coats,
then sanding with a guide coat to make sure I get all the pits and orange
peel sanded down, then spraying three more coats and repeating the sanding,
again with a guide coat.  In a lot of areas that has not been enough, so
I've got 8 or even 9 coats of primer on some areas.  The stuff is not very
tough, so it's easy to sand right through.  On my first ES, I used DuPont
Corlar, a two-part epoxy primer.  By doing the spraying quickly, wearing a
respirator with two fresh charcoal canisters, then opening the windows and
leaving the hangar till the solvents cleared, I was pretty satisfied that my
liver was safe.  The Corlar was a bit more work to sand, but it was tough
and came out with a beautiful finish, smooth, no pits, no weave, and ready
to paint after just a few days' cure.
    The unsettling thing about the UV Smooth Prime is that it seems to keep
curing and keep shrinking for weeks and weeks.  You can put guide coat on an
area, sand it mirror smooth, then come back in three or four weeks, spray a
little more guide coat and sand lightly, and presto!, you see the weave
again.

    Top Gloss (water-based):  This just is just a b___ to spray.  The manual
supplied with it says an HVLP sprayer is OK, but my results with mine were
horrible.  I either got dry spray or sags.  When I called the factory and
spoke with their rather grumpy tech, he told me I had to use a conventional
spray rig.  OK, so I tried that, too, and the results are only a little
better.  The margin between not enough paint and too much is so thin that
I've found it almost impossible to get a decent top coat, and that's been
with horizontal surfaces.  I can't wait till I try the vertical surfaces on
the fuselage!  In the end I opted for trying to get a slightly dry coat,
figuring I'd take it down with the wet sanding and buffing later.
    Well, I've now finished my HStab.  It was primed, then sat for a couple
of months, then was top coated and cured for another month or month and a
half before I touched it with sandpaper.  Again, as recommended in their
manual, I started with 600 grit, wet-sanding, but found out it makes
scratches that are too deep to get out without a lot of work with the 1000
and up.  So, on the rest of it I started with 1000, then worked through
1500, 2000, a buffing compound, and then a swirl remover/ finishing glaze.
The gloss is nice, but I'm apalled to see the cloth weave coming back
through in some areas.  The film build also seems very thin, and I went
through a couple areas down to the primer, so it'll need more touch-up, and,
probably, weeks more of curing.  The Top Gloss, like the Smooth Prime, has
not seemed to stop curing (and shrinking), even after sitting for weeks and
weeks in 70+ temperatures.
    By the way, I tried to repair a small area after only about a week cure,
and found that the edges would not sand, but kept peeling off as a film.
After sitting for another few weeks, I did manage to sand it and feather in
some more top coat, but the experience didn't inspire confidence.

    I'm now seriously contemplating sanding it all off and switching to
PPG's DCC or CLV.  I've probably spent $1600 or so on the primer and paint
(the primer doesn't seem to go very far), which I may just write off as a
bad learning experience.  I think I can top coat over the UV Smooth Prime,
but if, after several more weeks, I find the weave has re-appeared in the
surface, I'm inclined to think it will keep shrinking into the weave for
some indefinite period, so maybe I'll have to sand it all right off!
Arrrggghhhh.  There goes a couple of hundred hours.

    My advice re the water-based paint:  Forget it.

Jim Cameron, ES #2 in progress (at times)


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