Prepping a bumper for paint

Becaused it'll look like shit.

If you don't even know what type of paint you need, forget it. The finished job is only as good as the prep work and you don't have a clue.

How much? I'd not bother unless it's a lot as it becomes easy to blame any faults on your prep work.

Sand to 600 then 800 grit and everything feeling glassy smooth. Don't use aerosol primer, if there's any priming to be done, let them do it. Proper primer is approximately 1000 times better than the crap you get in rattle cans.

I posted a step by step guide to priming and spraying a new bumper on uk.cars.classics if you have a google.

You hve negativity ooozing from every pore. Which is very common in your posts.

£70 for the bumper £50 for the wing. I see your point. I have seen the work they do and its pretty good.

Ok, makes sense. I thought I could highlight any minor discrepencies by priming it myself to see for any little marks that ill stand out. I was contemplating buying some 1k primer and shooting it through my airbrush which is on a compressor, unfortunately I don't have a spray gun so might not be the gratest of jobs. As you I'll let them handle the painting. Halfords paint is very thin and piss like.

I'll give it a read, top stuff Doki.

Very helpful post. Thanks

That's a fairly decent amount then. I suspect for that amount they may be expecting to get panels ready to topcoat, whereas all you're really capable of doing is getting them in a fit state to prime.

You want to use a rattle can of black paint sprayed from a fair distance for a guide coat (what you were thinking of doing with the primer). The problem is that primers other than two pack tend to shrink back and expose flaws after a while. Even two pack will do if it if the flaw's bad enough. You also need to feather back the sanded area a very long way into the area that's still got paint on it. I'd only go to 400 or 600 grit if they're going to prime over the top.

Not really. I've just seen plenty examples of s**te which cost more than getting the job done by a paint shop.

I'm interested in reading the guide, but couldn't find it ?

It's in the last month or two, and I've not changed posting names in years, and I rarely post much to classics, so it should be an easy find.

Ok I only looked for recent posts. I'll dig a little deeper.

BTW from reading that other post why do you use a rattle can of black paint on the bumper ? does it highlight bits you missed ?

You mist on a very light coat from a good distance, and yes, it shows bits you missed. Most importantly, bits you missed because they're low spots. An imperceptible low spot in primer will look s**te with a gloss top coat on it. If it's a new bumper, the prep is much reduced, as per my post in classics.

Successfully painting plastics is an art, due to the extreme amount they flex, expand and contract all the time. Paint just falls off, as does filler. After properly preparing the bumper as per Doki, you must use a proper plastics primer and then high build (usually thinned abit with some extra plasticiser) primer, scotchbrited lightly, then the top coats (with added plasticiser) and finally the laquer (if metallic), again with plasticiser.

You are aware you will need to repain the whole bumper to get any sort of decent finish?

I've just had some work done on the S70, one of which was repair a parking knock on the rear bumper and repaint it. £110 sounded dear, but having got the car back (additional work done too-including a wing as it happens!) the finish and match is simply outstanding- I wouldnt even think about attempting it myself- as its silver any mismatch would look bloody awful.

I would totally recommend the firm I used to anyone, though as with anybody who is any good, they have a 2month waiting list.

TBH, 70 quid for the bumper is cheap as it goes (unless its a very small car / bumper) if you've not used the firm before and they cant show you any examples of their work, I would get it in writing that if you are not happy with the result, that they will paint it again FOC.

Tim. .

A new bumper shouldn't need any primer bar plastic primer. You shouldn't need flex additive either unless it's a really rubbish bumper, but it does help cut down chips and the like.

Does it have to be black for this to work ? as I have some silver and purple spray paint.

Also how light would this coat need to be ? not solid but just a dust on it ?

Doh forgot to ask. I have some davids isopon bumper fill to fill a few light scratches on my bumper I was given it as a joke as I bumped my bumper on a wall not long ago just wodnering if this stuff is actually any good ? or should I use something else.

It doesn't really matter what colour you use, but black gives a good contrast against most primer colours. When I put a dust coat on, I tend to do it from a foot or two away. You want it to look like it's had a light coat of black dust settle all over it. As long as the aerosol's spraying ok (ie, fairly full and not cold), you'll get fairly decent atomisation and it'll work fine. It's not a critical thing as long as you're not getting great blobby spots of paint an inch away from each other, as you might miss things then.

No idea. Given prep time and the fact that bumpers are slightly flexible and fillers generally aren't, I wouldn't bother. It'd be easier to get a new bumper - a brand spanking new one for my Golf is £40, and if new ones aren't cheap, just get a decent one off a scrap car for around the same money, scotchbrite it with a grey scotchbrite, do the normal prep work (ie, panel wipe) and spray topcoat onto it. OTOH look harder at the scrapyard and get a matching bumper off a matching car.

Conor