The driver’s side fender is a used original that I bought at Hershey last year. It had no serious rust or damage, but it did have some dents, and it was painted in primer.
I started by stripping off most of the primer, and found some filler underneath it. So I sanded off most of the filler and soda-blasted off the remainder of the primer and filler. It turned out that the upper surface had gotten rather beaten up once upon a time, and it had been somewhat roughly beaten back into shape. The top appeared smooth due to the filler, but the underside was pretty bumpy.
I decided to buy an air-powered planishing hammer from Harbor Freight, and I used it (along with a shrinking disk on my grinder) to get the upper surface smooth again. I was quite pleased with how well this tool worked. I also used it to get rid of some deformation along the outer edge and around the headlight bar mounting area.
The two mounting holes on the front inner surface of the fender are supposed to have a raised dimple around them, to make a nice fit to the oval-headed mounting screws. These commonly get damaged on old fenders, and the ones on this fender were smashed flat. Fortunately vendors sell special dished washers that can be used to restore the mounting holes. I got some of these, and brazed them into place over each hole.
Finally, I sandblasted the entire fender with extra-fine Black Beauty compound to remove all traces of paint and rust. After sandblasting, I noticed one small crack just inside the front edge, parallel to it. Repairing this was a fairly easy welding job. (Interestingly, both of the car’s original fenders had cracks in the exact same location.)
Now both fenders are ready for painting, but it is already mid-fall, and the weather is getting colder…