Goose bumps on hull

Peter · Post by **Peter** » Sat Dec 18, 2004 12:41 am

I'm in the process of re-building my San Juan 24. It's sitting in a fully enclosed Stimson Marine-type plastic covered enclosure, with ventilation at both ends.

I sanded several layers old paint off the hull, right back to the gel coat, and used Du Pont 1141SC 2K Urethane Primer-Filler to resurface the topsides.

Two coats and a lot of careful wet sanding later I had a beautiful fair and smooth hull surface. This was back in early September, in the warm dry weather. Since then I've been working on other parts of the boat waiting for that warm dry weather to reappear so I can give the topsides a nice coat of bright red Imron.

Today, as I was walking around the boat, I ran my hand over the hull near the bow and discovered several areas where the hull surface is covered with minute 'goose bumps'. Horrors!! Does this mean I have to paint it white now?

Does anyone have any ideas about what may be happening here?

Thanks!

Post by **Tim** » Sat Dec 18, 2004 9:01 am

Can you tell me more about that product you used? I'm not familiar with it.

Offhand, I would say you have a moisture problem--somehow, moisture got behind the surfacing product. One possible source is moisture from within the hull itself; another would be the ambient conditions at the time of application.

That sounds really frustrating, though, and I'm not sure what to suggest. I suppose in a way it's better to identify the condition now, rather than later after you've slaved away on your shiny paint job.

If the condition is widespread, I don't see many options other than removing the surfacer and trying again. No fun...

If you have more info, let me know. It might help.

Peter · Post by **Peter** » Sun Dec 19, 2004 12:05 am

After a little exploratory sanding I suspect water in the fibreglass itself. The primer/surfacer was put on under ideal conditons (too expensive to do otherwise) and is a recommended substrate for Du Pont Imron topcoats.

I'm wondereing if, after sanding off 3 layers of old paint and some of the gel coat too, that some trapped moisture was then able to work it's way to the skin of the hull.

Anyway, I'm over the shock :) and have decided to just let it be until the spring, then re-sand the trouble spots, re-prime them, and shoot the paint on right away to seal it up again ... that is providing the goose bumps don't turn into huge warts.

I'm hoping a few months sitting in a well-ventilated shed will help. Meanwhile there's enough other things to do, and above all else, I have to remember this is all about going sailing!