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Got a gel coat question....

RIBS

New member
I have a 71 Bonita fiberglass boat, with some chips and gouges in the gelcoat, a few getting as deep as the fiberglass..what’s the best way to repair? A tinted gelcoat kit? Some sort of paint? Fiberglass resin? Most are diameter of a dime or smaller....a few above, a few below waterline.
 
Gelcoat basically is colored resin, I would go that route if you're looking to color match and get it back to a smooth finish like what is there. You could paint over plain resin depending on what the boat looks like, it wouldn't cosmetically look as nice. I have filled large voids with epoxy first that had deep cracks but without being to liberal with it because epoxy is tough to sand if you make a mess. Also you need a bit of a void to be there for gelcoat so when you sand you retain the color. I assume the ones below the water line are gouges in the bottom which is painted with anti-fouling? I would fill those with small dabs of epoxy, sanded smooth with 80 grit or so and cover with a bit of barrier coat then touch up with bottom paint. You could skip the barrier coat to save $ if you're re-doing the bottom at some point in the next 2-3 years, depends more if you trailer the boat or if it sits in the water for the year..
 
Thanks for the tips...this is a 50 year old trailered boat, so any repair won’t be under water for more than 8 hours at a time...the fiberglass and gelcoat are shiny and In great shape, garage kept...I will try a colored gelcoat kit, I am handy with epoxies and sanding and have done some auto body....so I should be reasonably successful! Most of the damage is trailer impact , or other things like that...a few chips where transom transitions to bottom of boat, one big one where boat jumped off front winch roller and an exposed bolt chewed it up...a few rock scrapes on keel from beaching over the years...I don’t plan on ever redoing it, it’s all original and looks like it could go another 50 years...all the chips are untreated so far, so I want to get them filled in and waterproof...if I can color match, even better!
 
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Thanks for the tips...this is a 50 year old trailered boat, so any repair won’t be under water for more than 8 hours at a time...the fiberglass and gelcoat are shiny and In great shape, garage kept...I will try a colored gelcoat kit, I am handy with epoxies and sanding and have done some auto body....so I should be reasonably successful! Most of the damage is trailer impact , or other things like that...a few chips where transom transitions to bottom of boat, one big one where boat jumped off front winch roller and an exposed bolt chewed it up...a few rock scrapes on keel from beaching over the years...I don’t plan on ever redoing it, it’s all original and looks like it could go another 50 years...all the chips are untreated so far, so I want to get them filled in and waterproof...if I can color match, even better!

The most common problem is the gelcoat not curing properly. Theres a good amount of how-to's out there on gelcoat and difference between wax/no wax gelcoat etc. The goal is to build up to a convex area that overlaps your damaged area so you have material to fair into the surrounding areas. I'd make a batch and go around hitting all the spots. A wax-free gelcoat would require the last coat applied to have wax added in order to fully cure. One with wax added already you would not be able to let set-up and add another layer like a wax-free. You'd have to get as much material that the viscosity allows you to put in the void and let it cure before adding more, probably more suitable for surface gouges, but still works. Either way- when the outer coat is curing, I like to coat with PVA mold-release to help entice curing and cut off oxygen. Has to be washed off before any subsequent coats are added. As far as sanding, you can usually get away with wet sanding 400-600-800 then buffing with compound to get back to normal. I'm sure you'll figure it out-Good Luck!
 
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