I fixed the base of the rear window in my Charger w fiberglass when I was 18, I'm 55 now and the repair is still working great ! Clean and no rust is the key.

Take care,
Rick
68 Coronet R/T 440 & 68 Charger 528 Hemi,and 5 Challengers! 6 cyl, 318, 360, 383, 451