The second thing is that sanded areas and cut edges of MDF are unpaintable. You have to seal them with something (spot putty or Bondo or the like) to get a paintable surface.

I really like Krylon - you have to work at it to screw it up. Rustoleum is a better finish, but you have to be much more careful and it takes forever to dry between coats (not my long suit).

Hope that helps.

Maybe I didn't sand well enough? I don't know, but I don't think that's the problem. It's like painting a roll of toilet paper, end on.

Bill

My latest painted project, the white speaks were sprayed by a friend with what he called "catalysed Acrylic" from Sherwin-Williams. I wasn't there when the work was done but did notice the primer coat was beige. He said "that was what was in the gun". I'll ask him if it was a sealer or just the paint thinned.
Other times I have brushed, rolled and sponged MDF never had the soak up problems but I was putting on very thick coats and then sponging a texture.
Let you know what the painter says as soon as I see him.

Those white speakers look great. I didn't any seal coat and just sprayed a few light coats of color. Primer would no doubt help!