I agree with the notion that sanding the frame after primer-surfacer would take more gumption than I have, I was trying to describe the effect. If it were my project, I would shoot a good brand non-sanding epoxy primer and a top coat of satin frame paint.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy