Advice needed: Resurfacing/Sanding of black textured/semi-textured plastic trim (exterior)

[sportscarhiatus]

I have black exterior plastic front bumper trim that needs some love and attention. I know what you're thinking, use Black WOW or GTechniq C4 or O.C 2.0... I know that will restore faded/worn trim... but what I'm asking about is if the trim is actually chipped/scratched/pitted from years of rock chip abuse, I would like to restore the surface to a smooth (or textured) finish BEFORE applying C4 or O.C 2.0.

So how would I go about doing that?

I was thinking of wet/dry sanding the surface to even everything out... and then spray painting it with some black flexible trim paint... like maybe Wurth or something like that?

So I guess, 2 questions really...

1) Do you recommend sanding the surface down to level then painting with black trim paint as the right approach before applying the C4 or O.C. 2.0? If not, what other ideas do you have?

2) If you recommend the above as the right approach, what sanding process (wet or dry or what coarseness?) and actual trim paint do you recommend???

Thank you in advance for your input.

 

[C. Charles Hahn]

Personally I would go a slightly different route than sanding and painting; on interior panels I've used a heat gun and grey scotch-brite pad to restore distorted hard trim panels with fairly good success.

By heating the material, depending on how the dye is impregnated into it you can re-flow the plastic making it easy to re-shape and to redistribute the color on the surface, and by hitting it with the scotchbrite while it is still "soft" with a little practice you can mimic the original texture in your finished result.

Here's a video demonstration (skip to about 12 minutes into the episode) to give you an idea what this looks like:

Powerblock | Tips For Restoring Cars, Trucks | Full Episodes | Spike | Trucks | Season 2 | Free Full Episodes | Spike

I haven't used this procedure on exterior trim but I would imagine it should work much the same as it has for me on interior panels and molded floor mats/liners.

 

[MaximumMD]

Well I think it depends on how bad the chips are. If there real bad and your sanding like 1/8" to 3/8" off the trim. Then yea of course you would sand first. Anyway you do it, I would do all the sanding first then put on your protective product of choice. Same thing if you were waxing a car. You polish first then wax. Not try to polish the wax smooth. So yes Sand, paint, protect. IMO