This nearly killed me! Took 3 days of sanding and spraying primer. The only limit being how strong my hands are. I used 3 different types of sandpaper, and normal red-ish primer. The reason I went for red (green would work better) was so that I can see all the bumps and imperfections in the light. You can't do that with white or black.

But I got it to be perfect. So it was time well spent. Time to put him into production.