Fixing what you should have fixed before paint
So 'my friend' has a bonnet that is fitted and painted and looks almost alright.
Unfortunately the 'almost' bit is really irritating.
There are a few high and low ridges that show if you look at the right angle. If this was still in prep then I would fill and sand but now it is painted.
Does all the paint and undercoat need to come off right back to the glass before starting the filling and sanding or will filler bond onto the paint/undercoat?
I know that either way it will need repainting, I just need to know how deep to sand, I mean my mate does, I would never be so silly