Bottom Paint Issues Along Scumline

May 19, 2016
127
Catalina 30 Riverside, NJ
Hello,

Prior to this season, I worked on the bottom of my Catalina 30. I had the bottom soda blasted, I made some minor epoxy repairs, I sanded and fared it as well, I then applied two coats of epoxy barrier (Pettit Protect Epoxy Primer 4700), and two coats of bottom paint (Pettit Hydrocoat Antifouling Bottom Paint). After the season I had the boat hauled and pressure washed and placed on stands. While cleaning the scum line I noticed the bottom paint looks like it failed along the scum line. I am not exactly sure why or what I should do to fix it.

I suspect that the barrier coat may have dried too much before applying the bottom paint. I applied the bottom paint within the time limit of applying the epoxy barrier for the given temperature, but the epoxy was not tacky to the touch, which is what I read was best for other bottom paint applications. i.e. Tacky to the touch, but no paint on your finger. Maybe it dried out on me by the time I got to that side of the boat or the scum line. I gave the scum line four coats of bottom paint.

What can I do to fix it? Do I have to sand the scum line and reapply epoxy barrier, then apply additional bottom paint? Or could I just spot prep it?

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May 17, 2004
5,028
Beneteau Oceanis 37 Havre de Grace
That’s a remarkably sharp line, more so than I’d expect if the problem was just the epoxy curing too much. Assuming you painted the whole height of the hull at once, not painting that line separately at a different time, right?

I wonder if what you’re seeing is just the effect of UV on the part of the paint exposed above the water?
 
May 19, 2016
127
Catalina 30 Riverside, NJ
That’s a remarkably sharp line, more so than I’d expect if the problem was just the epoxy curing too much. Assuming you painted the whole height of the hull at once, not painting that line separately at a different time, right?

I wonder if what you’re seeing is just the effect of UV on the part of the paint exposed above the water?
Well, it was a few months ago... but "I think" I applied the second coat of epoxy then removed the tape and went home. I came back a 4 - 6 hours later, applied new tape about 1/16th above the epoxy line, then began applying bottom paint. I even think I started at the boot top, with the intention I would apply multiple coats along that line. I never applied the second color, because one red gallon was able to cover twice and cover the boot top then some.