I am restoring a Datsun 240Z that has an excellent paint job but is covered with small dents from hail stones. Some of these dents are more than 1/8″ deep. I have two questions concerning the repair. 1. Do I have to sand down to the bare metal before filling or is their a filler that would work if I just scuffed up the dents. 2. Is there a filler you culd recommend for dents that could be a little deeper than an 1/8″. How about Rage extreme for both questions?