JJ

I'd always assumed that a lot of the moisture damage occurs the other
way around. When the trailer is warming up in the morning and the
glider is cold, when moisture will condense on the cooler glider
surface. I imagine this lasts quite a while until the glider warms up.
One of the concerns I've had with solar powered fans is that they can
pump cold moist morning air into the trailer that may condense on the
glider surface, then have to pump it out later that day. My little
project to build a humidity controlled vent fan for the trailer got
sidetracked. Maybe one day I'll get back to it.


Darryl


On Dec 23, 8:21 am, JJ Sinclair wrote:
Moisture in the trailer has reared its ugly head once again. The
trailer doesn't have to leak in order to get it in there, it can (and
does) come from condensation. Think about what goes on in there after
you put the bird away at 5:00 PM on a humid aftrenood? Sun goes down
and the outside gets cold, but the inside is still warm and moisture
forms on the inside of the trailer. By 9:00 PM the inside air has
cooled down, but the ship is still warmer than the inside of the
trailer and moisture forms on the ship. Only way to stop this process
is to put the trailer inside a building (that's where my ship is for
the winter) or open it up and let everything air out at least once a
month. Blisters can form on Urethane in about 3 months if the above is
ignored.

What to do? Re-finish it and use Acrylic Urethane next time which
resists moisture much better, but isn't immune to the moisture bug.
The good news is the re-finish of a blistered bird wouldn't be nearly
as much as re-finishing a getcoat'd machine..................probably
about half as much. I have heard quotes as high as 25K. I have been
working with a real craftsman who is getting into the re-finish
business here in the Western US. He is quoting 15K + materials (PPG
Acrylic Urethane is up to $400/gal and it takes 3 gal to do a 15 meter
bird). Send me a note and I'll put you onto this guy. Personally, I
think anyone is nuts to get involved with the nasty business of re-
finishing sailplanes which involves 300 hours of grinding, filling,
sanding, priming, contouring, more priming, more sanding, then finally
painting the nasty stuff (if you can smell it your killing brain
cells)................and your not done yet, next comes wet sanding
with 600 and 800, then buffing.......oh, I forgot the trim and
numbers and yes, Charlie, we'll be sure and put a big black number on
the underside of the right wing, then wet-sand and buff them out for
you.
My, My, how I have carried on, Cheers,
JJ