Having a hell of a time stripping paint

S

Siciliang35

Got my bumper off that has paint failure, parts of the bumper is peeling all the way down to primer.

Anyway I tried sanding it up yo 80 grit with not much luck.
Then I hit it with the air compressor and the air actually started flaking off some of the paint, I was able to get about 60% off between the air compressor and gently with the razor blade It was literally chipping off.

At the point where that stopped working I tried using aircraft stripper the new kind and that doesn't work, did research on that and it shows that they changed the ingredients and the stuff that made it work best they took out.

Then I went to harbor freight and got a sandblaster gun with black oxide and all that did was dull the existing paint that didn't actually take it off. What do you guys suggest
 
Mucho manuel labor. Remember when someone suggested replacing the bumper? You are finding out first hand why. Bumpers suck! There is no easy way that I know of. On something like that the procedure I would use would be air first, razor blade to see if any more would come off, then a da sander with 80#, but not all the way down to plastic. Switch to 180# to finish getting the rest of the paint off the places it will reach. Then hand sand with 180# the areas the da wouldn't reach. When it is all stripped, water sand with 320 to make the bumper smoother, wash with Dawn inside and out, clean with 700, wait 45 minutes, spray 1 coat 600-4 ad pro, wait 30 minutes, spray 2 wet coats SPI epoxy, wait 24 hrs. or longer, sand with 180# to knock off high spots, repair low spots with Evercoat 411 flexible putty, 2 more coats epoxy, wait 24 hrs. At this point it may be good enough to wetsand with 400, seal and paint, or it may need sanding with 220-320 and another round of epoxy. The new chemical strippers are about worthless other than leaving the skin on your hands, and I've never tried blasting a bumper with anything so I don't know first hand how that works.
 
Wet sanding or soda blasting are the only stripping options. Using abrasive media will just damage the plastic. Like I said before here:

Primer coats

I'm about close to starting this project which is a bumper. Never done this before. Does the tech sheet tell you how many coats of primer you should lay on? Let's say I paint two of the same bumpers everything the same except for the amount of coats of primer I put on. Will one bumper look...
www.spiuserforum.com

Honest opinion. Get a new aftermarket bumper cover. (they are relatively cheap) Have a good shop paint it. Then you install it. You are in over your head and are just going to make a mess. Not trying to hurt your feelings, but just trying to be honest with you.
 
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:D manual labor is working pretty good. It's taking a lot of time and patience but I will do what I have to. I'll be sanding it down and priming it soon but first I want to make sure everything is perfect
 
texasking said:
Mucho manuel labor. Remember when someone suggested replacing the bumper? You are finding out first hand why. Bumpers suck! There is no easy way that I know of. On something like that the procedure I would use would be air first, razor blade to see if any more would come off, then a da sander with 80#, but not all the way down to plastic. Switch to 180# to finish getting the rest of the paint off the places it will reach. Then hand sand with 180# the areas the da wouldn't reach. When it is all stripped, water sand with 320 to make the bumper smoother, wash with Dawn inside and out, clean with 700, wait 45 minutes, spray 1 coat 600-4 ad pro, wait 30 minutes, spray 2 wet coats SPI epoxy, wait 24 hrs. or longer, sand with 180# to knock off high spots, repair low spots with Evercoat 411 flexible putty, 2 more coats epoxy, wait 24 hrs. At this point it may be good enough to wetsand with 400, seal and paint, or it may need sanding with 220-320 and another round of epoxy. The new chemical strippers are about worthless other than leaving the skin on your hands, and I've never tried blasting a bumper with anything so I don't know first hand how that works.
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Question if I do get down to plastic what should I be worrying about and what should I do. Can I just go over it with 180
 
Siciliang35 said:
Question if I do get down to plastic what should I be worrying about and what should I do. Can I just go over it with 180
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On bumpers like yours, I strip down with 180 all the time because of time restraints. Make no mistake it will leave a "furry" mess, but it can be cleaned up with 320 wet good enough to accept epoxy. If you stop with 180 dry and prime over it, it will almost certainly need 2K to clean up which we are trying to avoid. Do not skip the wet sanding step. It will save you time and money. At one time I worked for a Ford dealership that sold a lot of Saleen Mustangs. Any time one had front bumper damage, most owners demanded a new one. Those bumpers came from Saleen bare plastic finished with 80# da. They were horrible. Even after lots of wet sanding they required 2 sessions of 2K to make them acceptable. This was a production shop so getting the job out was the priority, but the original bumpers were done the same way, with too much film build to take any impact without cracking. My point is, the coarser the grit you hit the plastic with, the more work it will take to make it smooth again. Sand more now, or sand more later, with now being the better approach quality wise. Oh, and I got paid 5.0 hours to paint those bumpers, which was $65, my part:mad:
 
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Any tips to getting every bit of paint out of the little small indent crevices.
kind of hard to reach I've been wrapping the sandpaper around different things what are you guys do to get into this tiny areas
 
I usually just fold a piece of 180 in half and use the folded edge to get in the small crevices. You're getting there.
 
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okay so I got all the paint off, I'm going over it with 180 dry and it seems like there's low spots I don't know if you could see but there's a little bit darker what is my goal sanding this down with 180, am I just taking out all the 80 grit scratches or am I going to try and take care of all the lows and highs
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That area where the bumper goes against the fender is too rough for primer. It will absorb the primer like a sponge. 80# scratches are hard to remove from bare plastic, but do the best you can to remove them with the 180, then spend some time smoothing with 320 wet. Any low spots like gouges or deep scratches can be filled after initial coats of epoxy with polyester putty, like the Evercoat 411. Just primed some motorcycle side covers with epoxy today after stripping with 180 and water sanding with 400 (320 works better, but I was out). Wiped with 700, waited 45 minutes, sprayed 1 coat 600 adhesion promoter, waited 30 minutes, then sprayed 2 coats epoxy (SPI, with 30 minutes between coats) after letting it induce overnight. The parts came out slick and will only need 400 wetsanding, sealing and painting.
 
That picture was when i first started. Here I got some pictures basically all done with 180. Few questions
There's a few little areas I got to hit, how how clean does it have to be where the side markers go because that's a pain in the ass.
2 is 320 wet equal to 220 dry?
going to rain tomorrow so I'm going to start with sanding after tomorrow and I should be able to prime it within a couple days.
 
It's your bumper, but I would get all the paint off at least where it will show. 220 dry is not equal to 320 wet. Even 320 dry, is not the same as 320 wet. Wet sanding with 320 will probably save you an extra primer session, and is a necessary step, IMO. Make sure you get the rest of that paint out of the crevices around the grill openings. That will be the first place it will bubble and peel because it was probably not sanded real well last time it was painted.
 
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You can use a propane torch to help burn off the 80 grit roughness. Don't hold it in one place too long. Just singe it. That will also help with adhesion.
 
One thing that hasn't been noted-skipping steps with the grits.

On wood, I sand 80-100-120-180, because wood is soft and the coarse 80 grit scratches take a lot of sanding with 180 to remove. By going 100 then 120 then 180, the 180 is only removing 120 scratches, so it is a lot less effort.

I am not a body man, so I am probably wrong, but isn't the plastic soft like wood? I get that steps can be skipped when sanding filler, primer, and 2K, but it seems to me that the plastic would be much easier to clean up using all of the grits.

Please correct me if I am wrong-I'm here to learn.
 
Siciliang35 Do as Texas said the 320 wet helped me on a 2015 Taurus ex law car front bumper cover with about 100 small chips and some peeling. Leson is turn down job or new cover!
 
I am certainly going to wet sand it only thing is I'm looking at the tech sheet for the primer and it says up to 220 for prep should I still do 320 wet or should I do 220 wet
 
How do I know when im done wetsanding
 
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Don't have anything that's fuzzy, there are scratch marks from the 180 but no fuzziness
 
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