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  1. #1
    Join Date
    May 1999
    Location
    Saco, Maine
    Posts
    71,830

    Default Stripping urethane bumpers

    Does anyone know the safest way to strip the paint off my urethane bumper? Is there a stripper that's made especially for this application?
    '70 Mach 1 - '72 Sprint - '94 F-150 XL -'97 E-150 - '05 Sable LS

    My Mach's restoration progress

    My Sprint's restoration progress

    "Those who can make you believe absurdities can make you commit atrocities." - Voltaire

  2. #2
    Join Date
    Aug 2005
    Location
    Suamico, WI
    Posts
    1,937

    Default

    I personally usually just sand it all off, what I can with a da, and hand sanding, then epoxy prime and wet sand the epoxy for paint (spraying on a guide coat to help see sanding progress and what you have missed.

    Even should be able to go somewhat coarse, 80 on the worst spots or to get down aways, and finish off with or go over where your down to the urethane with 180. The epoxy should fill 180 without a problem. Urethane doesn't see too bad if it is sanded with somewhat coarse paper, some other plastics get all fuzzy or just smear when you sand them. As long as you keep the sander moving and flat, shouldn't have a problem. If its peeling because of a bad past paint job, first try blowing off what ever you can with a blow gun or pressure washer, or try a razor blade.

    I am sure there must be some kind of stripper made for urethane parts, much like there is for fiberglass, but the thing that would worry me most about using stripper on it, is how the urethane could soak it up. I am not aware of anything off hand, cause I just sand em. Done enough peelers. Found this http://www.wmbarr.com/product.aspx?catid=1&prodid=45

    And as far as a flex additive (which should never be added to the base coat by the way, at least thats what I was taught, but after looking at bulldogs site, they for some reason say different), its my opinion adding one is a waste of money, and just something for the paint companys to get extra money out of you. Its my understanding that most of them eventually evaporate out of the paint anyways, and is more for installing purposes, if you are really going to be twisting the part around installing, and I've never had a problem installing a part without flex additive. Modern epoxy and urethanes are pretty flexable as it as, and after seeing a urethane bumper I painted without flex in it, that the guy totaled the car soon after, made that opinion stronger. Bumper was really jacked and twisted, and no paint was off, only a minor amount of stress cracking right where the major impact was.

    Doing an anal job of prep and sanding (wash well before even begining to sand to get rid of contaminates and not sand them into the surface) is the key to paint staying stuck. Nothing special is needed for urethane parts, I normally don't even use an adhesion promoter on urethane parts but wouldn't hurt if you did. The Bulldog brand seems to be fairly popular when dealing with plastics.
    Last edited by kenseth17; 12-12-2011 at 07:39 PM.
    http://victorylap.50webs.com
    Autobody. paint, and restoration, Green Bay, WI

  3. #3
    Join Date
    May 1999
    Location
    Saco, Maine
    Posts
    71,830

    Default

    What worries me with sanding is that I don't want to lose any of the crisp lines. It doesn't need any filling, it's a nice piece that just needs the paint remove. I'm also paranoid about it soaking up stripper.
    '70 Mach 1 - '72 Sprint - '94 F-150 XL -'97 E-150 - '05 Sable LS

    My Mach's restoration progress

    My Sprint's restoration progress

    "Those who can make you believe absurdities can make you commit atrocities." - Voltaire

  4. #4
    Join Date
    Aug 2005
    Location
    Suamico, WI
    Posts
    1,937

    Default

    What about doing the flat parts with a DA. Just keep it flat and moving, and crisp line areas by hand with a sanding block (sanding straight along with the direction of the line, not rounding over it). Could even go as far as taping one side of the line off, and doing 1/2 at a time. If you have a lot of time with a da though, lines shouldn't be a real big concern if you sand correctly, and don't round them all over with the da

    80 and 180 on the urethane might feel a bit rough, but epoxy primer will stick like glue and fill and lock down any roughness, then when you wetsand the epoxy for paint things should be nice and smooth. Any finer then 180 and you would be there forever and a year trying to remove paint or do anything I think. You could also block sand the primer/ reprime or spot prime if needed, to help get nice crisp lines. If it were a brand new bare urethane part, then could go much finer, but not when your trying to get paint off, and I think its a lot easier keeping things straight with courser grits then working an area forever trying to get anywhere.

    If you go the stripper route, then I'd follow there directions closely and be sure you got it neautralized well, and then allow plenty of time for stuff to evaporate back out of there before doing any priming or painting, or even let it sit out in the sun for awhile. I am not a big fan of stripper, and use it as little as I can, to me its too messy and caustic. I find it usually faster stripping by removing what you can if poor adhesion, and sanding the rest. Usually end up sanding to get off the last of the paint after stripper anyways.

    Whats the reason for stripping it? Is the paint not adhering, or just have old factory 1k paint on it that you want to get rid of and start fresh?

    One more option would be having it blasted. With the right media and experienced blaster, it might be possible that they could remove the paint without damaging the plastic underneath.
    http://victorylap.50webs.com
    Autobody. paint, and restoration, Green Bay, WI

  5. #5
    Join Date
    May 1999
    Location
    Saco, Maine
    Posts
    71,830

    Default

    Quote Originally Posted by kenseth17 View Post

    Whats the reason for stripping it? Is the paint not adhering, or just have old factory 1k paint on it that you want to get rid of and start fresh?.
    Yes, we'll be repainting the car. I think you're right and we should avoid strippers.
    '70 Mach 1 - '72 Sprint - '94 F-150 XL -'97 E-150 - '05 Sable LS

    My Mach's restoration progress

    My Sprint's restoration progress

    "Those who can make you believe absurdities can make you commit atrocities." - Voltaire

  6. #6
    Join Date
    Oct 2003
    Location
    Marietta, GA
    Posts
    4,405

    Default

    http://www.azautobodysupply.com/sem39bust17a.html

    Or soda blasting should work as well
    Luke
    For every minute you are angry you lose sixty seconds of happiness. - Ralph Waldo Emerson
    62 Fairlane Sedan
    65 "C" Coupe 351W/C4
    98 Cobra Coupe

  7. #7
    Join Date
    Oct 2003
    Location
    Marietta, GA
    Posts
    4,405

    Default

    http://www.autobodytoolmart.com/sem-...3-p-15362.aspx

    I'm not sure what the difference is... but ABT also has the one I posted in the above post a bit cheaper.

    Eastwood doesn't carry either.
    Luke
    For every minute you are angry you lose sixty seconds of happiness. - Ralph Waldo Emerson
    62 Fairlane Sedan
    65 "C" Coupe 351W/C4
    98 Cobra Coupe

  8. #8
    Join Date
    May 1999
    Location
    Saco, Maine
    Posts
    71,830

    Default

    I'm going to hand sand it, that's what my body man recommends.
    '70 Mach 1 - '72 Sprint - '94 F-150 XL -'97 E-150 - '05 Sable LS

    My Mach's restoration progress

    My Sprint's restoration progress

    "Those who can make you believe absurdities can make you commit atrocities." - Voltaire

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