Mechanical paint removal question

[dirttorpedo]

I'm stripping down a frame using a combination of sanding and a brass wheel on a drill. Things are going fairly well, but I'm wondering if its good practice to sand the frame down with increasingly fine wet dry paper to remove any scratches before priming and painting?

 

[mdvineng]

Use a filler primer on the bare metal, then sand down before next coat until all is smooth enough.

 

[Tootyred]

600 is as about as far as you need or want to go. Other wise you loose the key for the paint.