just wondering what the best way to get all the paint off of some rs bumpers i just picked up that need painted. i want to prep them myself and the paint is all cracked and peeling. anything i can use besides just sanding that wont hurt the plastic/poly. whatever the bumper is made of.

thanks, Matt

 

I also need to know this. What products that will strip paint but not hurt plastic actually work best? I would hate to just try something that may not work or worse mess up my bumper cover.

 

Im doing this right now. I use Spra-Strip paint stripper. Look at the pic. It was recommended by my body supply shop. I roughen the paint with a 60 grit on a da CLEAN, then use the stripper as directed. Still have to sand at the end, because it doesnt remove the gm original primer crap. I bought plastic parts primer to go with my paint system to use on raw plastic only, and I have all the gfx and bumpers done to the plastic now.

 

i am a painter and i do alot of custom jobs, i personally would just take the time with sand paper, i like it because your not trusting a chemical to do the right thing, with sand paper you know you are doing the wright thing. but if you insist on using a chemical, use "aircraft stripper" but i REALLY think you shouldnt go that way, to many things can go wrong and ruin your job.
just my

 

find someone who does water blasting... this will blast them completely clean, allow you to do any filling and whatnot to get any wrinkling out of them...

 

I think maybe alot of you are misunderstanding the question, at least my question. Like one of you suggested if I use stripper use aircraft remover. That stuff will eat a plastic gta bumber cover as easily as it eats paint. Sanding is also a big no-no with plastic. It gets all spider-webby and then your finish ends up looking like crap because you won't be able to see alot of the haze until the paint dries. I guess I know what you can't/shouldn't do. I was just hoping someone out there would suggest some product or method that I haven't tried before that would make it easier and work better. The best way I have found is hours of scotch brite type pads and rubbing. I guess I really just want to know what plastic safe stripper is the best?

 

What you cant/shouldnt do is be using stripper on a urethane bumper. Sand it.

 

if you would read i STRONGLY recomended that you dont use a stripper, i have never had a prob with aircraft stripper on plastic ever, and i dont know were you are getting your ****ed up info, but who in there right mind says you cant sand on a plastic bumper, i do it literally at least 5 times a day. procedure, p180, p320, p600 wet, prime, block with p600 wet, seal, paint, clear. if youve had a problem with sanding and getting spiderwebs in the finish, you have to sand it to the bare plastic, and you need to know what feather edging is, you need to learn to DO IT RIGHT and sand it, but you sound like you wanna do it wrong, so have at ityou need to just do it your own way if you dont want to listen to a proffessionals advice. dont ask if you dont want the right answer.

 

I knew some of you would get insulted. Sometimes it's hard to hear tone through type. I am hearing this ****ed up info from a guy in my garage, he's the body guy, who works for porsche as their body guy fixing the ones that are messes up during shipment. Alot are. He can fix them to be sold as new. These guys don't hardly use filler. In fact, he was just offered a job by them to teach their body techs in Atlanta. Their standards are way beyond what most body shops and hobbiest like me ever approach. HE told me that you NEVER sand plastic. Porsche has been using plastic and fibreglass for alot more than they have used them here. He is also not the only good body guy who has told me the same thing. Now don't get me wrong, I don't discount what y'all said and they could be wrong but why did you seem to get so offended calling my info ****ed up? Bigmaciroc, maybe you mean a dif aircraft stripper but the one i got is by klean-strip and it ate my old bumper cover when I tested it so I will not be using that. If anyone else takes your advice there, good luck. I realise you did say not to use a stripper and of course you CAN sand plastic. I am looking to have it come out perfect, better than factory. Maybe our standards are different. I also have my old cover to test with and sanding on the plastic causes little stringys. How do you ever remove them and have it not affect the finish? Some of you may choose to argue some of the points above, and I won't come back and say your wrong. So if you want to start a pissing contest go, but i won't praticipate. If I didn't need to know I wouldn't have asked. I really just wanted to know what plastic safe strippers were best.

 

Ultimately even sanding on metal is not ideal, because you will leave sanding scratches there as well.. if your eating up plastic by sanding your using too harsh a grit, or getting it too hot with the DA sander or whatever your doing..

sanding plastic WILL leave a different surface then you started with, as does sanding metal or fiberglass, this is why you have primer filler that you sand back down to a smooth finish before you paint

 

39913 - BUMPER STRIPPER

 

Bigmac is 100 percent correct. Sanding is no problem. Your buddy that is supposed to be a Porsche guru is feeding you wrong information, or you are misinterpreting the information. Ask him how they get the paint to adhere to the stripped part. You ABRADE IT!! I have prepped many panels, urethane, SMC, steel, fiberglass, you name it... we all start with the same process, we sand it. I have also stripped many panels with aircraft stripper, (GM delamination anyone?) and you ALWAYS have to sand the panel afterword. Aircraft stripper IS too aggressive for a urethane part. use the SEM product that ckjoshz28 supplied the link to. A NEW GM part is sanded before we paint it.... Primer is sanded. BONDO is sanded. Flat out you need adhesion.
If you're looking for a beter than factory finish, it doesn't come from "not sanding" a panel. It will come from the prepwork, (which will include thoroughly sanding all panels BEFORE primer... ) as well as the QUALITY of the materials you use, and your attention to detail.

 

If you are all about having a better than factory finish, please save yourself the time/frustration and go out and buy all new bumpers & ground effects, then just do the scuffing and spray them.

 

FIND A PLACE THAT DOES WATER JET CLEANING ON IT!

it doesnt damage the plastic, it takes it down bare of any paint...

otherwise if you do not want to go that route, sanding is what you will have to do - have fun!

 

by water jet cleaning you mean pressure washing?

what kind of pressure are we talking about? and wouldn't you have to sand it afterwards to scuff it up?

 

at least someone else agrees with me, Walrus, i work for a Lexus dealership paintting customers bumpers from small accedents. i have 74 I-CAR credits, im TELLING you, you need to learn to sand if you are having problems with it, believe me, are standards are probly different, mine are the highest posable. if this is what your porshe buddy does all the time, then why ask us? like i said before, go do it how you want, weve told you the right way.

 

Was reading through this thread, using the search button. I just wanna renew a paint job on my 87 bird, looking to go a different colour. I thought stripper was the easiest way, but i think the general concensus is to steer clear cuz it involves sanding anyway.

So heres my question. I need to strip the front and rear bumpers completely, you guys mentioned a progression of grits to use. Are they all wet or only the last couple before the primer? Finally what kind of primer are you using???? I will be doing the prep work over the winter, and the car will be shot with paint in spring. So i need something that doesnt have a time limit between primer and paint. If i need to scuff it before the paint, thats no prob. Id like to use a primer that will fill out the fine scratches, i can buff down the primer at the end no problems. Im in canada, and i have access to regular hardware stores, various auto parts stores, and NAPA, i need names, brands etc.... Plz advise.

 

Hi, I have been searching on Internet last two days on the proper way to prep a painted used plastic bumper that has large areas of missing paint. I attached a picture of the bumper I'm working on. Sounds like you do this kind of work for a living or are considered a professional for this type of work.
My first question is should I sand all the paint off and re paint the whole bumper or should I just try to fill in the areas of missing paint?
I'm assuming I should sand everything off so I'm down to the raw plastic. If I do that what kind of primer should I use? I have adhesion promoter but I'm not sure if I need a specific type of primer or not?
​​​​​​After priming you said to "block with p600 wet. I'm not sure what you mean by "block"? Are you basically just saying to sand the primer down by wet sanding with p600 grit sandpaper?
After sanding the primer you stated to "seal". I'm not sure what you mean by that?
The rest is pretty straight forward. Apply the paint the the top coat.
Any help is much appreciated.


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Many years ago I stripped my bumper with aircraft stripper and still had to sand. Anyway, I painstakingly sanded all the way to bare urethane on that one. I still had spider cracks that needed a high build primer. Anyway, I am just about to do this again with a used bumper. The paint is in pretty fair shape so I am planning to sand, prime, then paint. No stripper on this one. I don't have any opinion either way but I am not using stripper this time since it was a pain last time. By the way, a couple of months ago a guy dinged my front bumper on my 2010 Camaro in a parking lot. Insurance covered it and the shop ordered a new bumper. Even though it was new, they had to sand and prime the new one before painting.

 

One thing to note is your bumper on the caelica is i think plastic while third gens used urethane bumpers s there MAY be some differences.


​​​​​​After priming you said to "block with p600 wet. I'm not sure what you mean by "block"? Are you basically just saying to sand the primer down by wet sanding with p600 grit sandpaper?
He means to sand down the primer to make it smooth and to look for imperfections. You can use a guide coat... when you sand it down, youll see remaining guide coat in low areas. thats how you find hi / low areas. Creates a better finished product.



After sanding the primer you stated to "seal". I'm not sure what you mean by that?
Hes talking about using a sealer... basically you spray a sealer over the primer to prevent the primer from absorbing moisture or something along that line. I think its usually a watered down epoxy primer that is used before paint basically.

 

Hand and DA sanded all the blue paint off down to the factory surface.