On Sun, 23 Dec 2007 22:58:15 +0000, Peter Thomas wrote:

although i prefer gelcoat for repairability, in strong uv conditions
automative paints last longer, it is quite possible that nothing much
will happen to the LS3 for 10 to 15 years

I owned a glider for over 10 years which the previous owner had sprayed
polyurathane over the gelcoat. Repairs of small scratches and dings are
not a problem.

- Firstly clean off all the wax with acetone.

- Then sand out the damaged area.

- Brush with polyurathane primer (this is a thick coat which builds up
like gelcoat). You may need a number of coats. If you use quick drying
"hardener" in the polyurathane, the paint on the wing drys faster than
the paint in the cup gets hard. If you put the wing in the sun you can
paint a number of coats with it, waiting for each coat to set before
applying the next, before the mix goes off in the cup. You need to build
up enough material to facilitate the re-finish.

- Wait for the paint to harden fully. (8 to 24 hours).

- Sand (wet) to restore the profile. You should end up with a perfectly
finished job, except the repair will be yellow and the wing is white.

- Now spray the yellow with a coat or two of aerosol "appliance white"
spray paint. That goes on very thin and drys very quickly.

- Then can carefully wet sand the aerosol with 2000 grit (just a few
strokes or you will go right through the very thin layer), buff and
polish and the repair becomes invisible. (If the job is not 100% you may
get a brown "water mark" around the sprayed area - normally due to wax on
the wing, but even this is very easy to ignore and virtually
unnoticeable).

Currently I have a share in an LS3a that has gell coat which requires a
re-finish. I would never consider re-finishing a glider with gell coat
instead of PU, and I would not buy a new one without PU. If the factory
price for PU was not reasonable I would get it sprayed after market,
before the gell coat starts cracking up and needs heavy sanding.

If the refinish job on the original poster's LS3a was done properly, I
would gladly swap his blistering PU for our cracking gell coat. (But not
the rest of the glider, we have a totally sorted out instrument panel,
new chute, decent Komet trailer and lots of little things that make it a
very nice glider....).

Ian