Hi all,

I have some plastic wheel arch liners that I have brought from the dealer. They always arrive scratched.
The issue is the smooth part of the liner is visible in the engine bay so can’t be all scratched up.
I’m attaching some pictures.
What would be the best method of sorting this out please? Process and products?
Any guidance sincerely appreciated!
Thank you

Send them back and ask for a set of undamaged ones.

Reality is that plastic is very, very soft and scratches if you even look at it with the wrong expression. Painting it might be possible but the plastic flexes so much the paint probably won't last. Sanding the scratches out won't work - you'll just get a sanded patch and buffing or polishing is next to impossible since it's so soft and flexible.

You could put some silicone detailer on it to hide the scratches a bit, but it won't last. The other possibility is to use a heat gun on the scratches and try to melt them in. Need to be super careful - maybe try/practice on and old one first to see how much heat the plastic will take. Or, learn to live with it.

NFT5 wrote:Send them back and ask for a set of undamaged ones.

Reality is that plastic is very, very soft and scratches if you even look at it with the wrong expression. Painting it might be possible but the plastic flexes so much the paint probably won't last. Sanding the scratches out won't work - you'll just get a sanded patch and buffing or polishing is next to impossible since it's so soft and flexible.

You could put some silicone detailer on it to hide the scratches a bit, but it won't last. The other possibility is to use a heat gun on the scratches and try to melt them in. Need to be super careful - maybe try/practice on and old one first to see how much heat the plastic will take. Or, learn to live with it.

Been back and forth with the dealer for over a year. These are the best they could get.
I was thinking of using Upol Plastx. Just giving a light coat over the scratches. Would this work?
Would I need an adhesion promoter first at all?

Do you know what type of plastic it is? ABS, Polypropylene, ?

Generally, a quality adhesion promoter followed by Epoxy Primer prior to painting helps in flexibility and durability.

'68 Coronet R/T wrote:Do you know what type of plastic it is? ABS, Polypropylene, ?

Generally, a quality adhesion promoter followed by Epoxy Primer prior to painting helps in flexibility and durability.

I have no idea what kind of plastic it is. Its very flexible if that helps...
So I definitely do need to use an adhesion promoter and primer, then the paint?

Would I need to spray the whole liner or can I just spray the affected parts?
Many thanks

Reality check.

These are wheel arch liners, a.k.a. splash guards. Super soft and flexible plastic that will take the pounding of stones thrown up by the tyres and prevent most of the water splashed up under the guards from going further. Zero structural value and often have to be bent almost in half to fit. Some of the European car manufacturers use a thicker, harder plastic, but it's essentially the same.

The plastic has an oily feel to it when new - so probably full of mould oil and likely it is recycled, or mostly recycled, plastic and of rubbish quality, despite actually being suitable for the job.

IMHO adhesion promoter and epoxy, then paint will be an abject failure, even if you can get it to stick. The pounding from stones and other road debris will destroy the paint in no time.

Of course, if the car is a trailer queen, then go ahead and paint them, but if the car is being entered in competitions then the fact that they're painted, i.e. not original, will see loss of points.

As I said before, judicious use of heat, preferably using a heat gun, may very well work to soften the scratches, making them less visible. Practice first on an old one to understand how much heat that plastic will take before it turns, instantly, into a black puddle.

Hi Chris thanks for that reply.
I should have clarified that the top part of the liner is visible in the engine bay. Hence the reason it needs to be spot on.
If I can get the top part looking decent that would be great.
It’s understood the bottom part of the liner will be getting by stones etc so that won’t be touched by any paint that I use.
I’m only bothered about the top part and the best way of getting rid of the scratches you can see in the pictures…

I understand the application.

If you have an old one then try heat on that. The trick is enough heat to kind of melt the top surface, without making a gaping hole. Searing it. Will depend on the heat gun you use and temperature setting, but I'd try as hot as it will go to get the result in a single pass so there's no heat soak through the plastic.

If you weren't worried about keeping a glossy finish on the surface then you could also use an oxy torch with a big soft flame, but the risk is high if you get it wrong.

I too would try heat first depends on the depth of the scratch