(JJ Sinclair) wrote in message ...
Oh My, Ruben
It sounds like we have finally found someone who actually knows what they are
talking about. Your post brings up several questions:

for example when you wash your glider, then dry it and finally wax
it (because it is all clean now, right?), your drying was never really
able to extract the water from the pores.

Should we be waxing gelcoat? How about urethane finishes?

I think for this group, no.

I have seen little blisters that form when a sailplans is left in a very wet
environment, like a metal trailer. When these blisters are popped, a little bit
of water is evident under each blister. I have seen this in urethane and also
in gelcoat (Prestec) What is your take on this?

I have seen this. I don't have the one for all answer here, but I do
know that PPG is very quick to caution sanding the primer/filler too
thin, as it can cause lifting to occur. I think that once water finds
this void it will begin to collect with the water's own surface
tension drawing in more. And water can absolutely migrate from the
inside out.
I do think it is a part of the story with factory new finishes as much
as it is for refinishes, repairs, etc. The water really does not care
and all the work is done by humans who have been known to error.

I saw another question asking about UV. And folks, all of this is for
your reading pleasure (or perhaps not), so don't lose sleep.
So, does not waxing increase UV damage compared to a structure waxed
with a UV inhibitive wax? More complex question and looking at the
weekend owner/flier only, I would say yes, but not at a level you
would notice. Why? Because it is cumulative and mechanical damage
would more than likely occur first on a gross level before the effects
of UV were keeping you down. What about the white chalky stuff? Sure,
oxidized, damaged, UV affected topcoat. Buff it off and go fly. How
much UV exposure does your glider see in the box? How much, if left
rigged over night, in the dark? I might be going out on a limb here,
but I say very little. What would the group here say this flier flies
in a calendar year? 50 hours, more? If I chose 50 hours added 25
percent (for time not spent flying, rigging, staged on the line and so
forth) to represent the time of total exposure to the UV for the year.
That is 62.5 half hours for that year, right? At the end of ten years
we would have 625 hours. Not quite a month's worth of continuous UV
exposure. What about 20 years for this owner. 1250 hours. Just shy of
two months of continuous exposure. If your topcoat of choice can't
handle that, Oh boy. What about in your region's winter months when UV
intensity is generally at its lowest level. Hmmm.

Reuben
Interface Sciences Corporation
President / Director of R&D
www.interfacesciences.com
A&P / IA
California teaching credential in 'Plastic and Composite
Manufacturing'





JJ Sinclair