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Stripping these plastic bumpers for repaint

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Old 02-04-2022, 12:21 PM
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Stripping these plastic bumpers for repaint

I am new to this forum. Sorry if this is repeated.
I have a 1990 FORMULA
How do I strip these bumpers? I am afraid to use the conventional paint stripper. Local body shop said that it would be fine. I think sketchy at best. Im worried the stripper will melt the polyurethane. So......How do i strip these? thanks.
Old 02-04-2022, 12:33 PM
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Re: Stripping these plastic bumpers for repaint

Curious as well.... most body shops these days aren't used to older cars / materials and just assume stuff works.


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Old 02-05-2022, 10:29 AM
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Re: Stripping these plastic bumpers for repaint

SEM and several other companies make urethane bumper stripper. I've never had great luck with them. You have to buy a bunch of cans for one cover and still hand sand/strip all the edges and crevices

The body shop is probably trying to tell you in a round-about-way that a few years ago they really nerfed the strength of typical strippers. Traditional Aircraft Stripper used to be too harsh. They used to instantly go to work and really wrinkle the paint. (other than lacquer, which kinda turned greasy) Even multiple paint jobs... Now, it takes a couple of applications over one finish, and you usually have to cover it with plastic sheeting.

That said, I would still mechanically strip the old finish, via D.A. and 80-120g... I know what I can do with my hands, and I am constantly feeling it while I'm sanding. Unless, of course...You have like eight paint jobs that you're trying to get rid of...

Last edited by KEVIN G.; 02-06-2022 at 10:41 AM.
Old 02-07-2022, 08:02 AM
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Re: Stripping these plastic bumpers for repaint

Every Urethane Stripper I have found has been DISCONTINUED!!!

Should i just use stripper and be really careful??

thanks
Old 02-07-2022, 03:59 PM
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Re: Stripping these plastic bumpers for repaint

You can try "Bulldog" brand, by Kleenstrip. They have made some good products for a few years. Try your local paint jobber...

I'd steer you to sand it, then. I get pretty leery of heavy strippers on urethane. I've seen them attack/swell the original substrates, and change them to alligator hide. Make sure you use soap and water with a scotch brite before and after.
Old 02-07-2022, 05:37 PM
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Re: Stripping these plastic bumpers for repaint

do you have any recommendations on what grit paper? i assume DA swould be easiest too


Old 02-07-2022, 05:40 PM
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Re: Stripping these plastic bumpers for repaint

Originally Posted by KEVIN G.
You can try "Bulldog" brand, by Kleenstrip. They have made some good products for a few years. Try your local paint jobber...

I'd steer you to sand it, then. I get pretty leery of heavy strippers on urethane. I've seen them attack/swell the original substrates, and change them to alligator hide. Make sure you use soap and water with a scotch brite before and after.
Do you have a recommendation on what grit to use?

Old 02-08-2022, 09:00 AM
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Re: Stripping these plastic bumpers for repaint

Depending on how may finishes are there, I'd probably start with 120...If you have one factory finish, 120 should remove it in short order. Having one finish on a 30 year old car is probably a pipe dream...so you may want to switch it up to 80. You really want to watch your D.A. skills though, you don't want to be tipping the pad on it's side (which inexperienced people tend to do because it acts more like a grinder at that point) as it can create half moon shaped divots in the PU. Stay moving, and feel the bumper from time to time, it doesn't warp from the heat like steel can...but it can still mess with the structure a bit.
Old 02-08-2022, 12:11 PM
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Re: Stripping these plastic bumpers for repaint

Originally Posted by KEVIN G.
Depending on how may finishes are there, I'd probably start with 120...If you have one factory finish, 120 should remove it in short order. Having one finish on a 30 year old car is probably a pipe dream...so you may want to switch it up to 80. You really want to watch your D.A. skills though, you don't want to be tipping the pad on it's side (which inexperienced people tend to do because it acts more like a grinder at that point) as it can create half moon shaped divots in the PU. Stay moving, and feel the bumper from time to time, it doesn't warp from the heat like steel can...but it can still mess with the structure a bit.

Thanks!
I'll try...worth a shot... I got some spiderwebbing on the paint on the sides sadly. I got some experience but I'm no pro... definitely gonna go at it slowly!!!

Old 03-24-2022, 08:21 PM
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Re: Stripping these plastic bumpers for repaint

I sent mine out.
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Old 03-25-2022, 12:17 PM
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Re: Stripping these plastic bumpers for repaint

those are gorgeous!!


Old 04-01-2022, 12:08 AM
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Re: Stripping these plastic bumpers for repaint

Originally Posted by TEDSgrad
I sent mine out.
To who?
Old 04-01-2022, 08:23 PM
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Re: Stripping these plastic bumpers for repaint

Can't remember, but if you have peeps, anything is possible. Don't give up so easy.
They do hold a shine!

Old 04-02-2022, 10:52 AM
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Re: Stripping these plastic bumpers for repaint

Those are Keystone wrappers...did you "send them out" or replace them with "new aftermarket"? If you did indeed send them out, how were you assured that they recond your existing GM parts and return them to you? After dealing with Keystone for many years, my guess is, they didn't.

They look good, regardless...much better than the majority of Keystone parts.
Old 04-02-2022, 01:26 PM
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Re: Stripping these plastic bumpers for repaint

Such a skeptic. I've never heard of Keystone.
I did etch my initials inside the bumpers - I am very proud (and lucky), that after 220k miles all the panels are original on the car! - minus the wing, of course.
New wheels arriving tomorrow!
Old 04-03-2022, 11:12 AM
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Re: Stripping these plastic bumpers for repaint

Keystone is an aftermarket and reconditioned crash parts provider. You have wrappers from the company under your bumpers. That's what caught my eye. You told the other poster that you couldn't remember the company that reconditioned them.
Not a skeptic if I have had business dealings (mostly poor) with the company in question. Just relating my prior experience for the community.

As I said, yours look great, and adding your initials to the parts was a great idea that I never would have thought of.
Old 04-04-2022, 10:55 PM
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Re: Stripping these plastic bumpers for repaint

Sand with 180, spray a light coat of adhesion promoter, and prime. Sand the primer with 320 grit, seal and paint.

Im a professional painter at a Chrysler dealership's body shop. And i have redone quite a few of these cars.
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