Hull finish

[BillBrush]

So from what I gather, most people who build their own boats use marine paint as a finish over several coats of epoxy/fiberglass.  Most production boats use a gel-coat to finish a straight fiberglass hull.

So are gel-coats just a real pain to apply for a home-builder?  Too costly?  Not appropriate for a plywood boat?  Can you take an old tired gel-coated plastic boat and paint it?  Could you take a painted boat, sand off the paint and gel coat it?  Is there any difference between a gel coat and marine paint (from what I have read the answer is yes.)

I'm looking at various and sundry used boats and I'm curious how bad of a job it is to pretty one up.

Thanks!

Bill

[Andrew_Butchart]

On my boats I have what I call a 30 foot finish - it looks good from 30 feet way.  Saves me a lot of time with the sandpaper and paintbrush.  I also chose colours that would help conceal the bad carpentry and resin and paint drips and sags. -  ;D

[PAR]

Gel coat's main advantage is to help the manufacture's product "release" from the mold they made the hull in.

Gel coat can be applied in your driveway, but it's not easy to get a good finish. Environmental concerns, equipment needs and application skill will drive you nuts.

In short, gel coat is for factories setup for these types of coatings.

Yes, you can paint over it. Yes, you can apply it over properly prepped plywood.

The difference between paint and gel coat is gel coat is pigmented polyester resin, much like the resin used to make the production boat hull. Paint comes in a variety of chemical configurations, some are similar physically on a molecular level, but generally are thinner and have much better adhesion qualities.

As a rule, except for touching up a chip or other small surface blemish, you can forget about gel coat.

[BillBrush]

Gel coat's main advantage is to help the manufacture's product "release" from the mold they made the hull in.

Ok, now this makes sense to me.  If my brain hasn't left the beam entirely I can see how this would work for them.  They spray in the mold release, which, from something I read earlier today also hardens gel coat.  Then they spray the gel coat resin, in one of a variety of colors, then spray the fiberglass resin and lay in the glass.  Add the rest of the innards and presto, you have a boat.

I could see how this would be superior to painting based on manufacturing technique as it would speed up production greatly, and the finish would be ready-to-sell from the get go.

If I'm going to restore a boat, then I can just prep and paint as I would any other surface and it should work.  That's good to know.  I've been offered a Sunfish that's in need of some TLC so I'm contemplating fixing it up and selling it.