I had my mast unstepped this last weekend. Due to the age of the vessel and the aluminum to aluminum contact betwee the mast step and the mast, the step (What was left of it) came along for the ride.
Now I have to build a new mast step and repair the cabin roof. I've cut back to clean wood plywood on the roof and have installed a fiberglass plate with studs for the new mast step. I'm pretty confident in my ability to build a new fiberglass step and get it located where I need it to be. While I could leave the ugliness underneath the new mast plate for the next owner, I would not do that. I am going to properly grind back and glass the seam between the old deck and the new fiberglass plate, so will need to repair the gelcoat or paint.
I really don't want to paint. The whole boat needs to be painted and I just don't have the time or funds to do so.
Here's what I know:
Gelcoat on epoxy is an iffy proposition. It might stick and it might just pop off with a hard stare.
Polyester on epoxy produces a less tenacious secondary bond than is desired.
Gelcoat on polyester/vinylester resin is the right way to go for getting the best chance of adhesion.
I fair with 3M premium marine filler. It's vinylester based.
So, would the procedure with the best chance of success be to finish the rough in with epoxy, fair with 3M and gelcoat that? Should I overlay the final fairing with a coat of straight vinylester resin and go from there?
Thanks for any advice (other than paint it