hi jimmo, could you give me an advice? i'm painting my motorcycle plastics, i made all necesary steps on prep, removed all paint to the plastic, took me about 2 months remove it cause is the first time i paint something, applied the adhesion promotor and 3 coats of black primer with a 1.4 nozzle and the finish primer was very very smooth, do i have to sand the primer any way? or just paint on it?