Polishing Painted Plastic/Vinyl vs Metal?

[Swimmer]

Somewhere I recall a video talking about the differences in machine polishing plastic/vinyl car parts vs metal parts - i.e., car bumpers vs hood, roof, and side panels. Any differences or treat them the same? Or do you do plastic/vinyl by hand only?

[HeavyMetal]

All I can tell you is what I did. I did the painted plastic bumbers of my car, a friend's and my nephew's the same as the metal body panels. No reall diff in feel. My nephew's car is a Saturn Ion with the plastic body panels. Those polished out extremely easy - WG TSR and an orange pad was all that was needed. We did do the front clip with white/FG but saw no significant improvement. That may be the plastic, but more likely is the paint. I did the vinyl door pillar trim on my RAV4 with spent WG FG (waited until the polish broke down on a metal panel and then shifted to the vinyl). That worked perfect.

[richy]

You can buy a PTG for metal fairly reasonably. The same can't be said for working with plastic. So, having said that, you're working in the dark doing heavy correction. The HUGE danger with plastic is that it does not dissapate heat as quickly as metal does and therefore can get very hot, very quickly. It is paramount to frequently check the surface. Keep a spray bottle with cold water next to you. The other thing is use your rotary at as low rpm as you can and use more pressure to correct than speed. Wool is another very valuable tool for chasing deep imperfections in plastic. I can link you a thread if you want with more info based on a car I did with bad marks in the plastic.

[oldmodman]

My Mustang has a plastic hood, trunk and front & rear bumpers.
And I finish them exactly as I do the metal sides and roof.
I used Menzerna products in three stages and got a perfect (actually near perfect) finish.

[SeaJay's]

As Richy said since plastics don't dissipate heat as well you just have to be careful that the surface isn't getting too hot. Once the plastic gets hot the paint can come right off. I had this happen on my first real correction. Wasn't a big deal since the bumper on this car was a mess anyway. However, it made me proceed with more caution when I did my next car. Lower RPMS and more pressure is def the way to go. I actually prefer to use my DA on plastic bumpers if I think there is a risk that I may cause damage with the rotary. Just ensures there is less risk of causing damage.

[Swimmer]

Thanks. Now if the weather cooperates, I'll be doing some polishing!

[HeavyMetal]

As Richy said since plastics don't dissipate heat as well you just have to be careful that the surface isn't getting too hot. Once the plastic gets hot the paint can come right off. I had this happen on my first real correction. Wasn't a big deal since the bumper on this car was a mess anyway. However, it made me proceed with more caution when I did my next car. Lower RPMS and more pressure is def the way to go. I actually prefer to use my DA on plastic bumpers if I think there is a risk that I may cause damage with the rotary. Just ensures there is less risk of causing damage.

You know, it's posts like this that make me real happy I went with a DA.

[richy]

You know, it's posts like this that make me real happy I went with a DA.

Actually, no. You would need to use a lot of pressure with the DA and they don't respond well to that. What you need is a rotary with a truckload of torque that you can use at low, low rpm. HERE is a link where I explain/show what works on badly scratched plastic.

[HeavyMetal]

Actually, no. You would need to use a lot of pressure with the DA and they don't respond well to that. What you need is a rotary with a truckload of torque that you can use at low, low rpm. HERE is a link where I explain/show what works on badly scratched plastic.

You are talking about HEAVILY SCRATCHED plastic and the OP and I were talking about just polishing painted plastic bumpers and such VERSUS metal panels during a typical detail. There was no mention of heavy scratches by either the OP or I.