I used 3M Pyrahna putty to fill the pinholes. It's a 2 part putty that is easy to use and sands easily.
works very well for eliminating pin holes - and you can mix it so it kicks very quickly, which helps reduce cycle time on your preparation work (you can sand within 10 minutes). I only use this on shallow scratches or to eliminate pin holes in west system low density filler repairs. I use gel coat for repairs and have had no problems using this stuff. The guy whose shop Trey and I borrow uses Pirahna putty for final fairing and sprays Awlgrip - he has not had problems with this stuff.
You can buy additional 3M cream hardner at Home Depot if you use everything supplied with the product (I go heavy on the hardner to reduce cycle time 'cause I'm always short of time).
Chris.
