Hi all,

It's my first post here and was looking for some help in respraying a bumper. The bumper is currently red and in excellent shape but I want to spray it metallic sterling grey to replace the damaged bumper on my car. I remember doing a spray job a while back now and I seem to remember that the colour didn't turn out to be what was expected and I put this down to the original colour of the bumper being too dark. Is this right or am I talking out of my backside. If I was to spray both a white bumper and a black bumper both with metallic sterling grey, would they turn out identical in colour?

The bumper I have is red and I was going to grey scotch pad it to key the surface after is has been washed and degreased thoroughly. Then wash it again, allow it to thoroughly dry and go over it with panel wipe. I was then going to apply my first coat of metallic very thinly, wait 20mins, apply a second thicker coat, wait 30mins then apply my final wet coat. Will this be ok?

My main concern is that will the bumper need priming in a lighter colour first before applying the metallic sterling grey?

Thanks For your help guys

Alun

Given good enough coverage, two identical bumpers with different starting color should come out identical. The problem you might (or likely will) run into on color match is that silver metallic is one of the hardest colors to match, and will look different based on different variables - including the air pressure and spraying distance of your gun. Also the paint may have several variants, which your paint supplier ought to be able to tell you about.

It's a good idea to do several spray-out cards and note your gun settings, etc. Get it to match as close as possible before you spray the bumper. You could also blend into the rest of the car but a lot of guys don't do that on bumpers...you can find bumpers as-shipped from the factory on the car as it was first built/delivered and they don't match...

chris wrote:Given good enough coverage, two identical bumpers with different starting color should come out identical. The problem you might (or likely will) run into on color match is that silver metallic is one of the hardest colors to match, and will look different based on different variables - including the air pressure and spraying distance of your gun. Also the paint may have several variants, which your paint supplier ought to be able to tell you about.

It's a good idea to do several spray-out cards and note your gun settings, etc. Get it to match as close as possible before you spray the bumper. You could also blend into the rest of the car but a lot of guys don't do that on bumpers...you can find bumpers as-shipped from the factory on the car as it was first built/delivered and they don't match...

Thanks for the advice. I've just seen a YouTube vid and the guy recommends to give a good wet coat for the first coat, then a medium coat the second coat and a drop coat for final coat holding the gun further away and moving in all directions. Does that sound like a good method to spraying metallics? Also, I've just scotch padded it and have noticed quite a few stone chips, what will I need to do to get rid of stone chips before spraying base coat? Was thinking of buying some high build primer, then flatting it with say 400 W/D? I have some cellulose based high build grey primer from a job I did a while back, shall I use that or is it just best to buy some new 2K high build primer?

Thanks

Al

Also, if I do decide to prime it first, will the grey scotch-brite pad be enough for it to key properly?

Yes on fixing stone chips. No on the cel lacquer primer, stick with a 2k product.

I always used to use the maroon scotch pad, around 320 grit equivalent. On the spray technique, I never shoot a wet coat of base, just medium coats that flash off quickly. I do shoot a random drop coat as the last coat but I know a lot of guys don't do that. On a bumper it's probably not going to matter too much if you do or not.

Hi again,

I have another bumper to spray again tomorrow and this time the existing paintwork is in very good condition with very superficial scratches. I was thinking that this would not need to be primed and was just going to rub it down using 600 grit before applying basecoat. Will I need to prime it and is 600 grit a good or better choice than a grey scotch-brite pad to prep the surface? If this isn't right then what do you guys use to prep an already painted bumper that's in perfect condition?

Thanks again,

Al

Alun1976 wrote:Hi again,

I have another bumper to spray again tomorrow and this time the existing paintwork is in very good condition with very superficial scratches. I was thinking that this would not need to be primed and was just going to rub it down using 600 grit before applying basecoat. Will I need to prime it and is 600 grit a good or better choice than a grey scotch-brite pad to prep the surface? If this isn't right then what do you guys use to prep an already painted bumper that's in perfect condition?

Thanks again,

Al

Anyone?

It won't need priming. I'd go for a good going over with maroon or grey scotch pad as they are better for getting round all the edges and corners without breaking through. Maybe first flat the scratches with P600 wet though. Remember the basecoat has no build and scratches and defects will show through.

I managed to do a great job of my first ever bumper respray, great colour match, consistency and polished up well. However, I'm gutted as it is stone chipping very easily. What would cause it to stone chip so easy?

Overthick paint build is the prime cause of huge paint chips. Had the bar been painted before, making yours the third ? There are other things too, though. Some clears do tend to be a bit brittle, incorrect ratios when mixing paint/hardener/thinner, technique, flash off times, ambient weather conditions - all can have a contributing influence on the final result.