Originally Posted by miket52989
I used primer instead of ruffing up my vent bezels with sand paper. I feel using primer is a personal preference but when it can do nothing but help, why not?
Primer IS NOT a shortcut to properly prepping your substrate. If you are plainting any plastic parts off your jeep you should clean with a wax/grease remover, scuff, primer, paint and then clear.
You dont need to scuff with anything more aggressive than 600 grit and I typically wet sand. Plastic is smooth and needs to be scuffed to allow for maxium adhesion.
You should also be aware of plastic parts that are HDPE - this type of plastic should be flame treated prior to painting.
ABS plastic you can get away with lightly scuffing and painting directly to it.
Primer does a few things:
Allows better adhesion for paint
Fills in slight defects in the substrate
Reduces the number of coats needed of the base coat(color).