The pinholes appear mainly where fibreglass cloth was applied, and where filler like microsperes is applied, they would be air bubbles, but they are very very tiny and show up best to fill with the undercoat on, and probably show up even better in the top coat <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" />

Discussed on another boatbuilding forum is to apply the resin when the temperture is dropping, not rising, but apart from that I don't really know how to avoid them.

Hopefully work it out one day, maybe during the next project...

Regards