Painting A 309 Rear Bumper - Advice Please

[hoodygoodwood 70 3 Cars]

I need to spray a standard 309 rear bumper , what are my chances of the paint flaking off ? I have no experience of spraying and would like some advice on what preparation the plastic bumper will need and what type of undercoat or primer would be advised .

A 309 bumper is a thinner more flexible plastic with a fine rough finish than the 205 GRP ( ? ) type . I can get a new one from the French company to match the new front bumper but it will save £200 to use the existing one .

[pugdamo 111 2 Cars]

Are you painting it because it's faded? If so could you not just plasticare all the plastics, will probably be cheaper than painting the rear bumper aswell.

[farmer 328 1 Cars]

I would just get a new rear one and don't penny pinch, especially if you have a new front.

[allye 530 3 Cars]

Guessing its for the white turbo car with white bumpers? I'm sure miles is aware of dying plastics!

[theoilburner 7]

Zero chance of flaking off if it's done properly. I'm assuming you want to paint it a colour and not just restore the original grey plastic. If you want it 100% smooth follow this guide.....just be aware that everyone has their own way of doing it but having worked in a main dealer paint shop for 10 years the method I use has never flaked.

 

Rub the bumper down with red scotchbrite and panel wipe, the panel wipe cleans the bumper and gives the scotchbrite some bite. I then lightly abrade the surface again with coarse sandpaper - 80 to 120 grit (some people will not agree with this but any marks will be removed at a later stage).

Clean bumper throughly with panel wipe.

Apply plastic primer - professional stuff is single pack clear liquid.

Apply high build 2 pack (2k) primer with a flex additive. This is added to the primer to allow it to flex and reduce chances of cracking.

Guide coat and flat primer to remove texture and any scratches etc. As yours is white you'll get away with 500 maybe 400 grit but I always use minimum 800 wet n dry.

Paint it the colour you want.

Go to any paint retailer and they will give you what you need, technically they should only sell to trade due to the hazardous nature of the 2k paint but most are fine.

If you're not bothered about having it smooth don't abrade with coarse paper and just scotch, plastic prime, wet on wet primer then colour. You'll find the wet on wet primer will fill most of the texture anyway.

Job done.

Edited August 16, 2015 by theoilburner

[calvinhorse 870]

Mine have been painted and a part has chipped off (I'd imagine it got bumped) it looks like they used a lot of high build primer and flatted it first

 

On a second hand bumper make sure it's cleaned and degrease heavily to remove any bumper black / silicone based coating it's had in the past or you don't stand a chance!

Edited August 16, 2015 by calvinhorse

[hoodygoodwood 70 3 Cars]

Thanks Allye ,yes I am building a 309 turbo cup replica ( see my forum pic ) although it may be in blue not the white - the F + R bumpers are body colour on this car .I am ordering a new GRP front bumper from a company in France but would like to paint a std base model rear bumper to save me the £200 of a GRP replacement .The bumper is a 25 year old faded part as you would expect , I will not be using any recolouring products on it and was even thinking of leaving it in my garden to 'weather' for a while .

Thanks Jason , I will try and do it your way .If I was to take it to a paint shop how much might they charge to get the bumper to the stage that I can paint it myself . It might be more cost effective for me to have it done by a pro as I will have to buy all the materials and only have the one item to prep .

Edited August 16, 2015 by hoodygoodwood

[theoilburner 7]

£100 to £200 possibly, main dealer will probably charge a bit more. Labour is in the prep so may be cost effective to let them do the whole lot unless you have other parts to paint.

Edited August 16, 2015 by theoilburner

[hoodygoodwood 70 3 Cars]

I have been to a local motorfactors that has a paintmaking desk and they also do a range of plastic primers etc in rattle cans , they were U-pol I think . Would any of these be worth trying , it would be a convenient way of doing just one bumper .The 2 pack high build primer would have to be sprayed on in the normal way I suppose .

[Tom Fenton 1,541]

Don't bother with aerosols, the paint material by necessity to spray out of an aerosol can is too thin and doesn't give the build, if you want a good long lasting job on a plastic bumper it needs doing with proper kit.

[theoilburner 7]

U-Pol are quite good for aerosols, we used to use them in the body shop I worked in for small repairs , they do a high build primer but to do a bumper you'll probably need a few cans which may end up costing as much as getting it done properly as it's still quite thin (as Tom said) If you want it smooth you could sand the texture off first then you won't need as much primer but it's a proper ball ache - but price it up and see how much it'll cost, as yours is white you'll get a half decent finish with rattle cans and a polish up after, and once on the car will look fine - only thing I'd worry about is durability and cracking with aerosols as opposed to professional job.

[hoodygoodwood 70 3 Cars]

I will be spraying the whole car white myself with the help of a couple of friends , I will try to do a decent job preparing the rear bumper so I only have to spray it once .

The rear bumper is now in my back garden , I will be giving it a good soak and clean inside and out to remove any dirt .I have plenty of time at the moment so will probably have a go at rubbing the bumper down so its fairly smooth to start with . Bought some Scotchbrite pads and panel wipe so hope to make a start soon .

I will be buying a decent size compressor later but might use the small one ( 50 litre , 2 HP ) that I already have to prime the bumper .