At 21:03 30 October 2013, wrote:
On Wednesday, October 30, 2013 3:45:26 PM UTC-5, Craig Funston wrote:
On Wednesday, October 30, 2013 10:59:24 AM UTC-7, dogger wrote:
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Searching the archives I found a long 2003 RAS thread about Gelcoat.
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was
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a good discussion involving several top people.
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What I got out of it was, there is not much a owner can do about
Gelcoa=
t
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life. Some real experts advise not to wax as it may keep any water
vapo=
r [
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? ] trapped in the Gelcoat and that could cause problems. They say
you
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want it to be able to breathe to some extent.
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Other experts swear waxing is good for the surface and waxing will
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discourage yellowing and fading.
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Why sailboats look good after many years seem to come from the fact
tha=
t
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when they come out of the mold they are not worked on further, the
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Gelcoat surface is left intact, while gliders come out of the molds
and
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there is a lot of work to be done to them, aggressive sanding to the
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Gelcoat seems to open minute cracks that can propagate, it seems,
says
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the
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experts.
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Me? I'm going to continue to wax. Makes me feel good. I like the
smell=
..
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Makes me feel like I'm trying to make a effort to keep the refinish
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n
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away for as long as possible.
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Boats survive better in harsher conditions because they use better
gelcoa=
t than the German sailplanes do. This has mostly to do with
certification
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requirements for anything "new". Tends to reduce innovation in that
area.
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It's such a pity to pay top dollar for new glider with a finish that we
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l know won't last more than 15 years.
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Craig

I suggest the difference to boats is due to the structural differences
betw=
een the two. Boats use polyester based resins as the matrix between the
gl=
ass fibers, all glider structure is based on an epoxy resins. Gel-coat
is
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a polyester resin that seems to like the same as a base over which it is
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plied. Bonding between epoxy and polyester polymers is more difficult
beca=
use of the chemical and physical(expansion coefficient?) differences.


The initial problem is resin shrinkage ,which leaves the mat proud ,so you

either sand the gell down or fill the hollows with wax
I heard the top European pilots were having there asg29's back to the works

after 2 seasons to maintain the Finnish
I used to hard wax but my current ship were had painted new .