KP21 or any other brand of epoxy is used to prevent rust.Thats why you put it on bare metal first!It's pretty expensive though.Another good thing is that it sticks to just about anything.I always sand KP21,PPG's brand (DP) may say not to ,I never used it.When I need reg. primer,it's always a 2k,I like "painter's pride" brand,It's cheaper but works great.don't ever use laquer primer for anything!,it sucks!(adhesion problems) I once mixed the wrong shit in my paint and it never dried,I was able to wipe the whole thing down with laquer thinner and never went thru the primer,try that with laquer primer.You can use the kp for the Durango or use an adhesion promoter then a 2k,either way,make sure you clean it good with a wax and grease remover first,then scuff pad or sand it to ruff it up a bit.(unless you get it preprimed)New plastic parts have a mold release on em(unless it's preprimed) so,clean it real good or nothing will stick.If your talking about the bumper cover,it's plastic,not fiberglass but the same applies for fiberglass.
For those that don't know,On bare metal,you can use an etch primer,then a 2k over that.Epoxy just does both jobs better! also,you can use one brand of primer and another paint and another clear but,don't swap activators or reducers until you know what will work and never experiment on a customers job (unless it's a freebee)
Jim /ubbthreads/images/graemlins/haha.gif