Painting plastic bumper trims

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Kalimsnor
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Tue Oct 06, 2020 4:04 pm

Hi,

I want to re-paint my plastic bumper trims. Below is an album with photos of its current state, not the prettiest sight. Any advice, tips or products I should use? My plan was to sand it down, cover everything non-plastic, put on a primer and then a bumper spray.

Kalimsnor
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Thu Oct 08, 2020 2:19 pm

Heating them up with a heating gun worked wonders!
HenryM3
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Thu Oct 08, 2020 9:57 pm

I have a car with horrid black/grey bits, I’ve put loads of different makes of trim restorer on and they’re all shit, fortnight later they need doing, tried heat, no long term results. Someone must know/recommend a paint or process that will last
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flybynite
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Fri Oct 09, 2020 7:37 am

HenryM3 wrote:
Thu Oct 08, 2020 9:57 pm
I have a car with horrid black/grey bits, I’ve put loads of different makes of trim restorer on and they’re all shit, fortnight later they need doing, tried heat, no long term results. Someone must know/recommend a paint or process that will last
Those across the pond go on about 'SEM trim black' but they go on about a lot of things :D It does seem made for the job but it is expensive to get here for what it is.

I have not heard about an equivalent available over here being as good. But you probably would't anyway. Most easy fixes don't last a year.

I would say you would be looking at using at doing a proper 2K paint job, all from the same paint system starting with their adhesion promoter.

That would last but you would have a distinct thickness of paint that would show if chipped.
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Tzantushka
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Fri Oct 09, 2020 8:50 am

If your budget can afford it - new parts are the way to go.
You can sell your old parts to help fund the purchase.
The Americans love Euro bumpers.

If you don't want to paint, a good ceramic coating will give you 1-2 years (depending on climate)
For plastic parts I have found CarPro DLux to be really good.
Don't need to remove the parts for good results.
- clean thoroughly with all purpose cleaner
- badly oxidised trim will benefit with run down with a 'magic eraser'
- wipe down with a 50/50 mix of distilled water & isopropyl alcohol (IPA)
- apply the ceramic coating as per instructions

Painting is a better long-term option, but requires more effort and removal of the part for best results.
SEM trim black is favoured for a few reasons - the satin black matches the plastic sheen well, good flexibility for plastic parts, great adhesion & durability on rigid plastic parts.
Other option is Duplicolor trim black + adhesion promoter, I found that a bit glossier.
I found SEM trim black easier to apply and followed this process:
- remove parts
- clean down with all purpose cleaner
- lightly scuff with a paint scotch brite pad
- degrease with a wax and grease remover (multiple times if you've been using a silicone based trim protectorant)
- wipe down with a tack rag
- adhesion promoter (if needed)
- 2 to 3 coats

There are other options such as trim dye (back to black trim restorer) but these can often end up streaky if not applied correctly.
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Lemon98
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Fri Oct 09, 2020 9:34 am

I removed them from the car (take the entire bumper off it's just two botls and then push out the clips from the inside) and sanded them down and then used ordinary satin black and it came out great!!

Mine is a facelift so not sure if the plastic parts are attached differently to the chromies.
1990 4-door 320i SE
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flybynite
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Fri Oct 09, 2020 1:01 pm

Lemon98 wrote:
Fri Oct 09, 2020 9:34 am
Mine is a facelift so not sure if the plastic parts are attached differently to the chromies.
They are attached differently but they are also a different plastic. You may get away with the FL in normal paint for a year or two but it won't work on a PFL it is too flexible.

As above replacing is best, (they were NLA but looks like they are available again)
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Brianmoooore
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Fri Oct 09, 2020 1:55 pm

Lemon98 wrote:
Fri Oct 09, 2020 9:34 am
Mine is a facelift so not sure if the plastic parts are attached differently to the chromies.
Take the bumpers off of the car, bring them indoors and crank the central heating up to max. for an hour or two before attempting to remove the trims by pushing back the fixing clips inside.
As I've said before, bringing the trims back to life professionally does not involve paint.
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Lemon98
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Fri Oct 09, 2020 2:35 pm

flybynite wrote:
Fri Oct 09, 2020 1:01 pm
Lemon98 wrote:
Fri Oct 09, 2020 9:34 am
Mine is a facelift so not sure if the plastic parts are attached differently to the chromies.
They are attached differently but they are also a different plastic. You may get away with the FL in normal paint for a year or two but it won't work on a PFL it is too flexible.

As above replacing is best, (they were NLA but looks like they are available again)
I also started off removing the trim with the bumpers attached and subsequently broke quite a few clips lol

Whatever the factory coating is on mine had worn off in a couple of corners so was white and I wanted to get it all looking black. Am happy with my DIY finish and if it doesn't last then I'll do it with proper replacement parts when I can afford.

I'll take some pictures of it soon, they look good imo.
1990 4-door 320i SE
Kalimsnor
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Fri Oct 09, 2020 2:44 pm

So can anyone tell me from first-hand experience how it went for them when they tried using a heat gun to restore the faded plastic? I tried it last week and it worked wonders, and I'm curious how long it will last.
HenryM3
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Fri Oct 09, 2020 5:34 pm

I’m atm trying to sort out the trim on my X5. Fortunately the M3 has very little black plastic plus it is always garaged when not in use. I heat gunned the X and it was great but 2 weeks later had deteriorated. Sure, if I done it now it would probably last the winter but I want something more permanent. The e46 with loads of black plastic I use a rag dampened with wd40 run that round the plastic, takes about 2 mins and lasts a fortnight, usually do it at same time as a wash and haven’t really come across anything better. Probably means you could never paint it but with the e46 at least you could replace it if feeling flush. The X has to much and to integrated into bodywork to replace.
I’ll be looking forward to the pics of the paint job on Lemon98s car when posted. Hint hint Lemon98.
DanThe
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Sat Oct 10, 2020 9:44 am

Painted trim never looks right, the reason they fade is the oil comes out of the plastic and the surface layer drys out, mainly from UV rays, which is why WD40/spray oils etc work well, a heatgun brings the oils further down up to the surface but you have to be careful its easily killed. Ive done well by soaking trim with oil and then using a heatgun in the past.
The best fix ive had on faded plastic trim is by using Gtechniq C4 Trim Restorer
Kalimsnor
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Wed Oct 21, 2020 12:08 pm

2 weeks in and the result from the heat gun is still perfect!
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