I like the idea of using a primer as a base coat. A primer is a bit softer than top-side paint, right?, and goes on thicker, so it's a bit easier to smooth out the canoe surface and cover some imperfections. But the primer is gray or white. I'm thinking that having a softer layer between the filled canvas & top-side paint might allow a scratch to penetrate deeper than it might if the primer hadn't used. Thoughts? Also, has anyone tried mixing some top-side paint with the primer so that hiding it's whitish color would be easier when painting?