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  Dec. 6, 2009 2:16 a.m. mad_machine SuperDork

  Been a long time since I painted a car.. and the last time I did, it was a fiat with chrome bumpers. I am hoping monday to have the body of my saab painted, but I still need to sand and prep the soft plastic covers for the bumpers.

  I know I need a flex agent for the colour and clear coat.. but do I need it for the primer?

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  Dec. 6, 2009 6:38 a.m. BoxheadTim Reader

  I defer to the greater knowledge on this board but I think you do, yes, unless you're using special plastic primer which should work OK without a flex agent.

  Then again, I might be talking out of my backside

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  Dec. 6, 2009 8:36 a.m. White_and_Nerdy Reader

  If the primer doesn't stick to the bumper, nothing on top of it will will have a chance. Seems to me the primer is the most important part, and should have a flex agent, or be that special plastic primer.

  Ironically, I've had 4 Saturns but never had to paint any plastic on any of them - and since their bodies are mostly plastic that's kind of amazing.

  - Justin

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  Dec. 6, 2009 4:13 p.m. aussiesmg SuperDork

  I found both a flexible plastic primer and bumper paint in aerosol cans at Advance Auto which has held up so far without issues

  Cornering is like bringing a woman to climax. Jackie Stewart

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  Dec. 6, 2009 4:27 p.m. EvanB HalfDork

  When I painted my Miata I just wetsanded the bumpers and painted them with the same paint as the rest of the car, no flex additive. It has held up fine for the last four years.

  Formerly jdmae92

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  Dec. 6, 2009 10:35 p.m. socalwrench New Reader

  Scuff up the bumpers (sanding them of course), clean them (alcohol, thinner, and/or wax cloth), and paint. If there is a decently smooth layer of paint, a primer isn't necessary. How smooth you want the paint is up to you as you can sand and clean between coats.

  For urethane bumpers- a flexible paint, such as bumper paint (aka polyurethane) is necessary.

  Greg- Owner/Operator: GRH Performance

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  Dec. 7, 2009 11:44 a.m. YaNi Reader

  socalwrench wrote: Scuff up the bumpers (sanding them of course), clean them (alcohol, thinner, and/or wax cloth), and paint. If there is a decently smooth layer of paint, a primer isn't necessary. How smooth you want the paint is up to you as you can sand and clean between coats. For urethane bumpers- a flexible paint, such as bumper paint (aka polyurethane) is necessary.

  A flex agent is not necessary. Modern urethane paints will flex just fine. I have a friend who is a chemist for PPG tell me that.

  Adhesion promoter, epoxy primer, high fill primer, epoxy primer, base, clear

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  Dec. 7, 2009 1:16 p.m. dansxr2 Reader

  http://www.wmbarr.com/product.aspx?catid=1&prodid=72

  We used this at our tech school body shop. Works well and is also a flex agent too.

  '91 Stg 2 Corrado G60

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  Dec. 7, 2009 1:21 p.m. pinchvalve SuperDork

  I can tell you this. Whatever Earl Schieb uses does not flex. I backed into a post last week and my bumper paint cracked like glass.

  When I think of something witty, I will add it here.

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  Dec. 7, 2009 1:42 p.m. kreb Dork

  What filler (If any) will do the trick? I can't imagine bondo cutting it.

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  Dec. 7, 2009 1:53 p.m. kpm New Reader

  kreb wrote: What filler (If any) will do the trick? I can't imagine bondo cutting it.

  Evercoat 411 Poly Flex flexible glazing putty works great.

  Oh and +1 on the Bulldog adhesion promoter !!

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