Hi! Guys.
All this talk about solvents .... gives me the willys for MKI builders and
polystyrene filled parts. I'm no specialist ..... but make sure the
polystyrene isn't susceptible to them , otherwise any solvent passing
through the glass cloth will disolve it underneath. Just for information
,Hans, on top of the Polifibre I used Pro-Desoto (Formerly Cortaulds) CA
40,0000 and activator and their
Gloss coat carries the UV Protection. (Sensibly priced too compared to the
Europa Pack. I had heard that Europa were being approached by Pro Desoto to
supply an alternative.?
regards
Bob Harrison G-PTAG Europa 337/Jabiru 3300 Trike.
-----Original Message-----
From: owner-europa@post.aviators.net
Subject: RE: Finishing/painting
Speaking from an SP perspective, I would suggest any postcure be done after
applying the Hibuild. Hibuild is not like an ordinary paint primer as it is
really a fairing compound and is intended to act as a sort of very thin
filler that can be sanded back until the desired profile is achieved on your
component. This is why it comes in different colours: by alternating the
colours between coats,when you sand it back to get your profileyou can
more easily see the high and low spots. It isa solvent based epoxy product
but the solvent is to allow it to be easily coated/sprayed onto the job.
Once the solvent has evaporated, the resin and hardener cure in a similar
way to a solvent-free epoxy product like the 106 you are using for the
thicker areas of fairing.
By postcuring the Hibuild and the 106 together you will increase the Glass
Transition Temperature (Tg) of both systems to some degree (although this is
not highly important for a non-structural filler),but you will also take
out most of the shrinkage that might otherwise occur later. This shrinkage
is what can give fabric print patterns in your paint finish after the a/c's
been standing in the hot sun, particularly if the filler is only thinly
applied and the resin content of your laminates is low (as ideally should be
the case). By sanding after both 106 and Hibuild have been postcured you
will have the opportunity to sand away any 'print-through' that may have
occurred in the postcure process. Your final painting will then be onto a
surface that is unlikely to shrink and print much more.
On the paint front, when high-performance composite yachts are painted, as
far as I know no separate silver layer is used. Modern 2-part PU paints
(such as the Awlgrip range from US paints), are extremely good at both
filtering out UV from the layers underneath the paint, and being UV-stable
themselves and not fading or discolouring. They're not cheap but they do
work well!
Hope this all helps.
David
-----Original Message-----
Subject: Finishing/painting
Hi all.
I have filled and sanded my Stabilizers prior to priming/painting. I'm doing
this prior to fitting the top- to enhance the balancing procedure. The
manual states that a second bake must be done after filling -
beforepriming, and my question is: Is this really necessary?? My stuff is
the British SP 106, withExpencell that came with the kit - and for priming
I'm going to use Hibuild from SP.
My next problem is UV protection. Do I have to apply silver before paint, or
can I just spray on a layer of clear Polyurethane UV protection as final top
coat?
I'm approaching this first painting of mine with a certain awe, and should
be very glad if any of you "masters" out there could shed any light on this.
(I'll have a Pro doing the actual spraying though!).
Hans, #334
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