# Advice on spraying plastics



## TTsi (Jun 7, 2009)

Hi,
Im after a bit of advice fro you guys,
Ive recently brought a Vivaro with the black plastics which i wish to colour code in Glacier White.

In the past when i have done this i have cleaned the plastics then used a plastic adhesion promoter then high build primer then the colour coat, which looked great for around a year before it started to peel off in places.

Can anyone advise the correct process in which i need to prep and paint to make sure that the paint will not flake off in the future?

Also can anyone advise me on a good plastic cleaner and adhesion promoter?

I will be using Cellulose based paints with a gun and compressor.

Thanks in advance.


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## VenomUK (Oct 13, 2011)

I'm interested in help with this too please.


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## Rayner (Aug 16, 2012)

No idea on what to use but you want somthing flexible as primer and top coat as plastic is a lot more flexible than metal.

don't know if cellulose would be up to the job?


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## Hasan1 (Jul 1, 2011)

You need to key the area first then use plastic car primer. To key it use a very fine wet and dry


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## mk2gav (Nov 10, 2012)

When I helped out a body work pal I was told to wipe tge surface clean with thinners, I did this about 3 times to ensure it was all clean, then I applied a product which I can't remember on which helped the paint adhere, iy was then primered, flatted then prepped for painting, I will pop to the bodyshop today for you and find out what the product was called, or im sure a paint suppliers would happily help out?


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## Andyb0127 (Jan 16, 2011)

Leave it with me at work at the moment. I'll do a write up tonight for those interested. :thumb:


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## TTsi (Jun 7, 2009)

Thanks Andy.
That would be a great help:wave:


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## Andyb0127 (Jan 16, 2011)

With plastics it depends what sort of texture the moulding or trim has to it. Because you need to bare in mind that, if you just plastic prime, high build prime, and flat and paint it. What will happen it will look great when first painted, then as the paint cures it will slowly sink into the texture on the plastic. Leaving the finish looking more satin/Matt. To cure this problem you will need to sand the plastic.

Preparing plastics for spraying.

As long the texture is very fine, this Wont take much to make smooth. Clean the trims first using a solvent panel wipe, this will clean any grease dirt or contamination of the plastic, no real need for a plastic cleaner solvent degreaser will be fine. 
Once it's all clean you'll need some water with fairy liquid as this is a detergent as well, which will also help clean it and act as a lubricant when wet flatting the plastic. To make the plastic smooth you will need to flat it with some P400 until the texture has gone. This may take a while then for a finer finish you'll to go over it again with some P600 this should of now made the plastic trims very smooth. They will is need drying of properly and solvent degreasing again to make sure it's very clean prior to priming.

Plastic primer should always be used on plastic, as it an adhesion promoter for the high build primer. It does comedy aerosol can form. What you will see is a 1K plastic primer no need for any type of mixing as its ready to use. This is a fairly good make of plastic primer in the link below.
https://www.google.co.uk/url?sa=t&s..._YCQDg&usg=AFQjCNFITUoDJwZ03Wr8btdoN-mfD-PKSQ

Now your ready for priming, make sure the trim is clean and dry. Applying plastic primer, shake the can as per instructions. No need to put this in heavy just a couple of light coats will do, leave for ten mins to dry. Now you can apply your primer of your choice, upol aerosol primer aren't bad can be found in Halfords.

Primer just apply a nice even coat no need to whack it on heavy. Leave if for around 15-20 mins, then apply another coat, three to four coats should be fine they only need to be nice and even and left between coats to dry as this is how the primer will get build between coats. Leave this over night to dry properly.

Now you will see to guide coat the trims. Guide coat is just a very light misty coat of black paint over the primer, reason for guide coat is that when you flat it the guide coat will be removed its used to high light any imperfections in the primer.

You will need flat the primer with some P800 wet flatting paper, same again using water with some fairy liquid in it. Slowly flat the primer until all the guide coat has been removed your primer should now be nice flat and smooth. Take your time doing this as every part of the prep work has to be right, it's all in the prep how the paint turns out. Make sure again the primer is cleaned and dried properly and again solvent degrease them, if all has gone well they should be ready for spraying.

Dependent on the colour your spraying, in honesty I'd get aerosol cans from a paint supplier as they can match it properly and the aerosol can will be better quality than those ones in Halfords.

Applying colour before anything make sure there absolutely clean, wipe over with a tack rag, a tack rag is a sticky cloth used to remove any dust or dirt prior to spraying. Just gently wipe it over with the tack rag, no need to apply any pressure to it just gently wipe it over. Read instructions on aerosol can shake for correct Ammount of time as this will make sure the paints mixed properly.
First coat will just need to be a very light coat known as a gripper coat, leave for ten mins. Then apply nice even coats leaving for 15-20 mins between coats depending on spraying temperature, apply coats until covered, if its a metallic once covered, the last coat should be a drop coat which will help the metallic sit even. It's paramount that you leave it to dry between coats, and you DON'T need to flat it between coats.

Applying clear laquer just needs to be applied in nice even coats take your time with this, as above leave for 15-20 mins between coats. Hopefully your plastic trims should now look how you want them. 
Remember at all times that every stage of the preparation is what will make the paint job. Don't rush any part of it.


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