why do you have to sand primed surfaces before painting?

Question

I get why you have to sand a surface before priming – it removes imperfections and creates a smoother surface. But why do you then have to sand again before painting? Surely by doing that you’re just sanding away all your primer?

In: 1

Answer 1

Ideally you are sanding the primer with a very fine sandpaper, so that you aren’t removing the primer. It’s to help set up the surface with exactly the texture you need for the paint to stick and look good.