I spent an hour sanding off the previous application of Superfil. Does this sound familiar? Anyway, this time I went all the way down to 220 grit paper – previously I'd been staying at 80 grit.
Now that the shape is basically how I want it, it's time to start preparing the surface by making it smooth and filling pinholes. For this job I'm using DuPont 210S, a single-part surface primer.
You're supposed to spray this stuff on, but it was too windy outside to spray effectively, and I didn't feel like getting out my spray gun and trying to mess with painting inside the garage. So, I just brushed the surface primer onto the skirt with a cheap foam brush. I'd never do that for a finish coat, of course, but for a filler coat it actually worked pretty well.
I put one one heavy coat, sanded with 400 grit, then applied two additional lighter coats without sanding in between. No rhyme or reason, I'm just winging it based on what seems reasonable as I go.
I kept the skirt up off the table with little balls of aluminum foil, to prevent the surface primer from getting all blobbed up along the bottom edge.
This is a picture of the third coat dying. The brush marks should sand right out.
It's starting to get smooth and look pretty good… is that the light at the end of the tunnel I see up ahead?