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I am looking for the proper prep and paint for plastic bumpers both previously painted TPO and also for a new urethane bumper lip that has never been painted. Both are on front bumper of the car.I will be finish painting in gloss black. Will the Rustoleum or Brightside paints hold up without spiderwebbing or cracking? Do I use an adhesion promoter for prep? Primer over that? I would like to use a simple to touch up finish paint without clear coat for easy maintennance for parts that will surely get stone chips. Any advice will be appreciated.



The front bumper on my Mustang was 'factory fresh', unpainted and in its original black flexible plastic. I used both Brightside and Tremclad on it... plus I also used a spray bomb on it.

The first and most important thing you have to do with a 'fresh' plastic molded part is to seriously wipe it down with mineral spirits. What happens is that these molded plastic things, use a 'release compound' in the mold, so that the item ( a front bumper for example ) will easily release from the mold when it is ready to be released from the mold.

This 'release agent' is normally not too visible to the eye or to the touch. But it lurks in the pores of the formed plastic. Since it is designed to enable and assist in the release of the plastic from the form mold, you can be assured that it will work to also repel paint or primers in an equally effective manner. So seriously wipe it down a couple of times with mineral spirit to wipe and wash away that 'release chemical' off the plastic part.

On my car... I went to a primer instead of going straight to painting on to the plastic. I seriously believe I could have gone straight to painting on the the plastic front bumper without any problem.

However, I used a primer on the entire car to start the entire paint job off from one uniform color starting point. You may recall that my car began as a car of 'many colors'. ( white hood, black plastic front bumper, red body panels ). So I brought them all to a uniform dark gray primer color...

Now.. as to questions of spidering or cracking on flexible body parts : The Tremclad/Rustoleum or Brightside fair no better or worse then a regular paint job. But the roller paint job does have some advantages over a 'real' paint job.

The Tremclad/Rustoleum or Brightside paint job tend to have a little more flex or forgiveness to them. Whereas the sprayed on 'real' paint job tends to be just a bit harder.

When a TR or B paint job on a flexible bumper is flexed, the paint tends to flex with it. The 'real' paint job tends to have less flex to it and it will crack sooner when flexed.

Now... I will tell a quick story that reinforces how a TR or B paint job is better. When I initially finished painting my car and polishing it into a shiny little jewel, I STUPIDLY backed the car out of the garage and caught the rear bumper on the barbeque. It placed a 5 inch SCRAPE along my beautifully finished rear bumper. I cursed, I swore and I cried.

Now the first thing to note is that it 'scratched' off the paint where the barbeque had scraped against it. It was a clean scraping right down to the plastic. But it did not affect the paint beyond the actual point of where the barbeque scraped along it. As you know, if the same thing had happened to a 'real' paint job, the odds are that the extent of the damage to the paint would have extended beyond the point of contact of the scrape. So that was a good thing.

Ok... so here is the good news. I simply drove the car back into the garage... sanded down the area of the scrape to make it all level ( feathering the edges of the scrape and the paint ). Then over the next couple of days I simply re-rolled that area where the scrape had occured. Once it was up to par I did the wetsanding, polishing and waxing and the scrape was totally gone and invisible. No one would be able to find that 5 inch scar unless I pointed directly at it. So the beauty of this is that the 'roller paint' job puts the task of 'touch ups' completely within your control. No need to live with a scrape or tie up the car at the body shop while they do a pro-paint job to repair that scratch ( which could cost you $500 to have done ).

Now... on the topic of the front bumper... the Treclad/Rustoleum are pretty resistant against road chips etc. But i would have to say that Brightside is probably better at withstanding road chips. The reason : Tremclad/Rustoleum are just enamels, whereas Brightside is a polyurathane.. ( think plastic ).

Now... one other fast thought about front bumpers. What you might want to consider is to paint a clear 'gravel gaurd' coating over the lower sections of your front bumper. This is something that will work for some people and not for others. It will really depend on the style of your specific front bumper. On some front bumpers you will be able to apply the clear gravel guard coating over all the areas below the bumper line... on other styles you may only be able to apply the gravel guard coating on the lower four or five inches of the front bumper. It will depend on your specific front bumper style. But the advantage of putting the clear gravel guard coating on there is that it is designed to withstand the impact of rocks and porupines etc. And so it will help to protect the paint job beneath it.

Dunno... those are a few fast thoughts on the topic.

Marq

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