Re: Marine Paint Sugestions
Wow, Bond-o,
I'm painting my boat because I don't want to mess with gelcoat, but I haven't deluded myself into thinking just because I chose paint, it is better.
Well, I think I'll jump in with another 2 cents worth.
Gelcoat is the best known coating for fiberglass hulls (so far) as far as durability and looks.
The big thing with gelcoat is that it's harder than paint... this is its blessing and curse. If paint goes on smooth and self levels (like many of the more expensive brands do) then it can come out shiny smooth when it dries. If not, you can sand, wet sand, and buff it.
Gelcoat can also be sanded, wet sanded, and buffed, although it's more like sand, sand, sand, sand, sand, sand, wet sand, wet sand, buff. It's harder and tougher than paint, get it?
Imagine if it were possible to coat a fiberglass boat in molten titanium without damaging the hull... how long would it take to sand that coat smooth and shiny? It'd be much easier if you did it in a mold, right? How long do you think it would last?
Paint is less durable, but much, much easier to apply in a non molded situation. Many people know how to spray paint fairly well, most modern marine paints are chemically formulated to give good results in a home or small shop environment (as in, not the boat factory). Gelcoat is gelcoat.
Gelcoat can be sprayed on , but even someone knowing what they're doing can get it too thin or thick. Plus you really need a gelcoat gun, not a paint spray gun (you can get by with a modified paint spray gun) It won't self level, and when it hardens it's a pain in the rear to sand.
Plus it's poly resin based, and the adhesion properties of that resin apply. If the surface it goes on is improperly repaired, then it can pop off. Poly is not a very good glue, it doesn't stick hard unless it's chemically bonded.
Gelcoat is designed to be the finish coat for molded fiberglass parts. You can make it work in other situations just like you can carve a boat from a big block of wood instead of planks and frames... few people want to go to that much trouble if they really understand what's involved.
Rare is the person who, working at home, can re-gelcoat a boat and have it look anything close to shiny. Oops! Here is an exception in a lot of ways, and he spent days (literally) sanding his gelcoat and making it fair and smooth. I believe he also had the gelcoat applied professionally, although it's been a while since I re-read his thread.
For almost anyone doing boat work at home, paint will give a better looking result. Careful choice of paint plus quality prep work will give a long lasting finish, up to 10-12 years for a daily use boat and longer if used intermittently (these are the sort of numbers claimed by Awlgrip and Interlux). This is longer than most people will own a boat, so it's effectively "forever".
So... if you're choosing to re-gelcoat your boat for the same reasons you'd repaint your car, think again... several times. It's not like repainting, it's more like you're fixing dings in your doors by taking the body panels off, pounding out the dings, sanding, wet sanding, repainting.... it's the long way around.
Unless you're either very ambitious and have a couple free days a week to work on your boat rebuild, you probably want to use paint. Really.
Erik