I clamped the S-602-1 backplate in my vise and began shaping the inside cut-out with a rotary file-spent about an hour with the die grinder to get the biggest chuck of aluminum removed. Next I used a drum sander on an electric drill—just barely removed the blue line I had traced earlier. Followed up with a scotchbrite wheel in the die grinder. Then more sanding with fine emery cloth. Looks good. I used a scotchbrite pad on both the doubler and backplate. Ready for primer-but it’s been raining all day—so will wait for a sunny day.
