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  1. #1

    Question Bumper Cover Paint cracked, Solutions to the problem?

    Hello,

    Looking for advice on how to fix and prevent paint from cracking.



    Is this the root of the problem? Yellow plastic base is cracked. What is the best Approach to fixing this?


  2. #2

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    There's a flex additive you add to paint to keep it flexible

  3. #3

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    Ps. These bumpers are VERY hard to keep paint on even with plastic adhesion promoter and flex additive. I'm sure a painter will come on here and get more in depth, but even in a perfect world you may still have trouble getting it 100%

  4. #4
    Moderator wraithracing's Avatar
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    Unfortunately there is not simple solution. The yellow plastic/urethane used in the Fox ear bumper covers is very difficult to repair and work with. The later model aero cars ended up going to a better urethane that holds up better and is easier to work with, but back to the issue at hand.

    If you have major cracking issues, then I would seriously consider having the cover media or soda blasted to strip down to the base material. This will allow you to make any repairs directly on the urethane if needed and not over old cracking paint or other issues. There are some specific urethane bumper primers such as SEM that can help to clean up and fill in cracks, chips, weathering, etc. This is often the best option after blasting to spray a couple of fill coats over the cover and then lightly sand the cover down to give you a nice smooth, crack free surface. After that you should be able to repaint and as long as the cover doesn't get hit or bumped hard your cracking issues should be solved. You will want to consider a flex additive for the covers, but I recommend verifying that with your paint suppliers. Some already have the flex additive in the paint and adding more can cause more issues than correcting them. As with a flexible substrate, keeping your mil thickness of paint to the minimum necessary for coverage can help to improve durability and help to prevent cracking and chipping. Obviously you need full coverage of color and at a minimum of 2 coats of clear if BC/CC but generally there are no benefits to more coats than necessary. Hope that helps and good luck!
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  5. #5

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    Quote Originally Posted by 79mustang View Post
    There's a flex additive you add to paint to keep it flexible
    Is there a recommended brand type that has been used successfully?

  6. #6
    FEP Power Member STL79Coupe's Avatar
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    Watch soda blasting though. I had a rear cover SB and it chewed is up and left a horrible texture. We eneded up using another cover and sanded it down. I'm not sure what went wrong with the SB.
    Keith formerly STLPONDS
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  7. #7

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    If you have major cracking issues, then I would seriously consider having the cover media or soda blasted to strip down to the base material. This will allow you to make any repairs directly on the urethane if needed and not over old cracking paint or other issues.
    I am using paint stripper as the method to get down to the base. That should suffice, right?
    There are some specific urethane bumper primers such as SEM that can help to clean up and fill in cracks, chips, weathering, etc.
    Is there a particular SEM product you recommend, Part number?... You will want to consider a flex additive for the covers, but I recommend verifying that with your paint suppliers. Some already have the flex additive in the paint and adding more can cause more issues than correcting them.
    Very good point.As with a flexible substrate, keeping your mil thickness of paint to the minimum necessary for coverage can help to improve durability and help to prevent cracking and chipping.Keeping the mil thickness? How can I verify the thickness? Obviously you need full coverage of color and at a minimum of 2 coats of clear if BC/CC but generally there are no benefits to more coats than necessary. Hope that helps and good luck!

  8. #8
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    Flex additive only make the paint flexible for a short period of time. It is only meant to allow installation before it hardens fully. It gives you some time to work, but will still harden over time.

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