Bottom Job Questions

[SailingWebGuy]

I began scrapping the old anti fouling paint off the bottom today. I'm not going to do the bottom job til spring but couldn't help asking a few questions now.

Under the anti fouling paint is a layer of very hard gray colored paint. I assume it's a barrier coat because underneath this layer is the white gelcoat. The gray layer is extremely hard to remove.

I plan on doing a new barrier coat in the spring. Can a new barrier coat be applied over top of the old coat or does the old coat need to be removed?? I should also mention that there are spots where blisters between the barrier coat and the gelcoat popped up.

The keel has some issues I think. In some spots a very light scraping exposed lead. The gelcoat was extremely thin. Should the lead be sealed up before putting the barrier coat on?? If so, what method is recommended??

Thanks!

[sailingdog]

Yes, you can barrier coat over the old barrier coat. There is no need to scrape down to the gelcoat.

In the areas where the blisters are, you should sand the blisters away and then clean the hull there thoroughly, let it dry out over the winter and then re-barrier coat the area before bottom painting the boat. These are likely not osmotic blisters, but rather blisters formed over places the hull wasn't properly prepped.

The lead should be sealed using a barrier coat or epoxy.

[SailingWebGuy]

Hey Sailingdog!

Thanks! I have another question...haha. I bought the 3M Premium Filler and haven't used it yet. Can the filler be used over top of the barrier coat or will I have to apply it to fiberglass?

[sailingdog]

I wouldn't use the 3M premium filler. It is a vinylester resin, and as such has a fairly weak secondary (adhesive) bonding characteristic. I'd use thickened epoxy instead. Use cabosil or fumed silica as the filler.

[CharlieCobra]

Whatever filler ya use, apply it directly to the glass.