For bare metal i use 428 EX BARRIER PRIME by ppg .it IS A 2 pak ZINC PHOSPHATE EPOXY PRIMER FOR "WET ON WET". it flows on nice and the finish is semi gloss, and it comes in dark grey, white. The hardener is ex-9090 I haven’t had any trouble with this product, then ya ready for bog, polyester spray filler, primer, base coat, clear coat.