Trojan Boat Forum

I have 3 of these patches. Do I have to prime these areas before i paint on the bottom paint?

did you fill a through hull?

the answer is yes on the primer, follow the instructions for the bottom paint

im going to on mine, Just to be safe. I would rather my new paints be put over good material rather than just striaght fiberglass. IMO couple good coats of primer then scuff it down before I begin the bottom paint process, Looks like a patched through hull from the dark circle I can see. I have one I would like to fill in but I think im going to stay away from that project.

Read the can

from pettit bottom piant

"Bare Fiberglass: All bare fiberglass, regardless of age, should be thoroughly cleaned with 92 Bio-Blue Hull Surface Prep or de-waxed several times with
Pettit D-95 Dewaxer or 120 Brushing Thinner. Sand thoroughly with 80 grit sandpaper to a dull, frosty finish and rewash the sanded surface with 120
Brushing Thinner to remove sanding residue. Then apply two coats of Horizons, following application instructions. Careful observation of the above
instructions will help ensure long term adhesion of this and subsequent years’ antifouling paint."

dif brands may difer

agreed, BUT the can will advise you to spend more $ on their product when you really dont have to. Reading the can for procedure is a must. Using the products they say for procedure I cant agree with. What ever is equal and helps the budget.

From what I can see in the pic, that looks like bare fiberglass. IMO, it should be barrier coated prior to applying bottom paint. Simply coating with bottom paint does nothing to prevent water ingress into the fiberglass.

yes i took out 3 old thru hulls. a friend of mine who has owned and worked on all types of large commerial fishing vessels gave me all the materials needed to patch the holes and a crash coarse on how to do it. but never instructed me on what to do after. i have sanded the areas hard with 60 grit. its pretty scuffed up now. i will get some some primmer for it. i thought that was the way to go. just wanted some feed back. leaving the 3 old thru hulls was not some thing i wanted to do. you just never know how old they are or what can happen to them. now i have 3 less holes in the bottom of my boat.

maybe use barrier coated befor applying bottom paint , but no primer ( many botom paint ) read the can .

barrier coat. thats what i meant. i call that some kind of primmer/ sealer.

Barrier coat is typically a two part epoxy type coating such as Interlux Interprotect.

+1 on the two part epoxy barrier coat. Then paint two or three coats bottom paint of your choice.