Painting topside

[Frank mellin]

My freeman 24 has lots of hairline cracks in the gelcoat.they are so fine that to dremel them would be almost impossible and trying to do so i would probably lose the will to live!
Can anyone suggest an undercoat that would cover these blemishes before I apply a quality topcoat.

 

[KevinV]

My freeman 24 has lots of hairline cracks in the gelcoat.they are so fine that to dremel them would be almost impossible and trying to do so i would probably lose the will to live!
Can anyone suggest an undercoat that would cover these blemishes before I apply a quality topcoat.

I've just had an interesting time with this - even using multiple coats of 2-pack primer they drew the first coat of (2-pack) topcoat in - through the primer! I'm guessing the primer was just too thick for capillary action.
I hated the colour of that first topcoat anyway so it didn't actually matter, but knowing what I know now I'd have applied some topcoat to the areas first, sanded it all away and only then primed, etc

 

[PCUK]

You cannot cover these fine cracks. You need to grind off all the gelcoat in the area back to the mat/resin layer and then fill and fair with epoxy filler before painting.