Gelcoat on Expoy

[vintageray]

I'm in water over my head here I think. I've occasionally done repairs on fiber glass. Never messed with a gel coat. Made the repair area ready for paint by sanding, fairing, priming and then painted it. Why is it necessary to put on the gel coat. I see lots of boats here that are having major work done on blisters on their bottoms and the workers grind out the areas, repair with roving and cloth, then fair and paint. Same with repairs to areas topside. I will read up on it before doing some work that I need to do on my cabin top, but thought I'd ask since this thread is discussing it.

[cburger]

Quote:
A simple wash with clear water removes amine blush. No soap, no solvents. Then sand that washed surface with 80 grit paper, to provide the gelcoat with sufficient key so it won't run. Be sure to use non-air inhibited gelcoat that has a paraffin wax added.


Non air inhibeted gelcoat does not have wax added and is what is generally used for repair finishing. As the final step after spraying the gel on the repair the area is sprayed with PVA to seal the repair from air and aid the cure.

Professionals frown on the use of wax added geclcoat for exterior finish work. If you are really concerned about adhesion of poly based gel to epoxy repairs there are companies that make primers "Duratec" that is claimed to act as a tie coat.

[capngeo]

If then topcoat finish on your boat is already gelcoat, then a spot repair of the same, will blend in better. Some yachts have painted topcoats... On those paint is the obvious choice for repair.

[vintageray]

My cabin top appears to be fiber glass over plywood and painted. It's textured though and will be a bear to match the texturing. Not worried about matching the color as I be painting the whole thing. Thanks for clearing up the gel coat necessity question.