Painting the lower plastic trim to match the body

Has anyone any experience of the proper technique of how the wheel arches and lower plastics, along with both bumpers are painted to match the body?
I used to paint a long time ago, so have a good deal of knowledge.
I had a car a few years ago with faded arches, and because i wasn't confident in how to do it to make a good job, I sent it to a (quite expensive) body shop to have them painted.
The body shop guy seemed a little stumped at the technique to use in getting them to match, and when it came back it was acceptable, but not durable, and the finish seemed to come off.
I have seen another thread here:
www.4x4community.co.za/forum/showthread....0-Jimny-matte-colour
But to no real solution.
I ask because I have a Jimny with one faded arch, and whilst confident, I really need to know the right way to do it.
I do remember 20 or so years ago, I had a matt lacquer, which could be the answer,
Or is it simply the texture of the mouldings will create the matt effect?
I'd prefer someone with experience confirm the way to do it rather than experiment.
Thanks.

 

 

As said above you can get a specific plastic primer, any good paint supplier should be able to help if you go talk to them. It's normally only required if your existing paint is failing to adhere or its an u painted surface. Prime with this first, then primer / top coat / lacquer.
However, if your existing paint is well adhered I don't see the need for it, simple key with sandpaper should be enough. 
Go have a talk to a local supplier, they will mix the paint and tell you what you need and how to apply. Our local one does,  very helpful.
Avoid Halfords / Generic Auto stores, products OK but you need advice from the paint mixer / supplier. 

I painted the plastic panel on the passenger door using a pot of spray paint and spray pencil (large nozzle). It took a couple of coats and then some cutting back to get it even. I also applied a laquer afterwards.

I just bought the paint using the paint code, if anything it is slightly lighter than existing paint which was a surprise given colours usually fade. Still if you spray the whole panel no one notices, especially as the finish looks different on plastic and metal.

I didn't bother with a primer, as it was still painted, just roughened the surface.

I took the panel off to do it in the shed, mostly as I have to spray on the car outside and the weather wasn't very good.

I have also had good results with aerosol cans, but the texture of the finish nearly always looks different. Go to someone who mixes then cans the paint if you go this route. Getting the right amount of paint down is harder with a can so expect to have a practice first, again taking the panel off and doing it inside helps.

I used aerosol primer, paint and laquer to re-fresh some alloy wheels recently, I was very pleased with the result, but the wheel paint is a semi matt finish which is always easier to spray.

Robin