I am going to remove the paint on the dash the previous ownerdid not spray on a primer on the dash which is why the paint chipped. My question is when applying body filler to bare metal such as a dash panel to cover small holes and even surfaces out, what grade of sandpaper should be used on the metal to prep so it adheres to the metal ?

 

180 is the finest you can use, and I wouldnt go much rougher than 80. You dont want deep gouges. Rough out the shape of the filler with 80, and finnish it with 220-400 grit. You want the smallest sanding marks possible, then prime it and sand with 400 and up.

 

its probably an type enamel paint on the dash and enamels are prone to chipping although they are scratch resistant