Question on urethane bumper refinishing
Thread Starter
6th Gear
Joined: Jun 2006
Posts: 6
Likes: 0
Question on urethane bumper refinishing
My 77's front bumper has a few paint chips, one large, and I need to know what can be used for filler prior to wet sanding and priming. Can regular body putty be used, or is there something else that is better? I don't want the repair to crack after painting. I know that a flex additive is added to the finish paint to give it flexibility, so I want to get it right.
Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
see the tech article by Lars called:
"Rubber Bumper Tech Paper.pdf"
on my website tech articles page.
http://69.253.166.197/page1/page65/page65.html
"Rubber Bumper Tech Paper.pdf"
on my website tech articles page.
http://69.253.166.197/page1/page65/page65.html
Burning Brakes
Joined: Mar 2006
Posts: 1,036
Likes: 2
From: Huntingburg Indiana
Sand the whole bumper with 400. Feather out the chips with 150. If the paint is thick you may need to apply some polyester putty. Otherwise, just build up the area with fill primer. It's a good idea to use flex additive. Block the repair. Now you can paint it. It's a good idea to use a flex in the paint also. When you fill prime, use a urethane primer. When someone says use acrylic, that's lacquer and anyone with an old car knows how good lacquer holds up. If you have any questions, send me a pm.
Last edited by bondoboy; Jul 18, 2006 at 10:14 PM.
Safety Car
Joined: May 2001
Posts: 3,758
Likes: 3
From: Surrey
Had the same with the front bumper cover on my '81. I spent 3 days sanding it down with 400 until all scratches/chips had been smoothed out (most of the time was spent removing a lot of the "wavyness" & getting it to sit flush - sanding down the paint didn't take very long at all). I asked the painter NOT to use any filler as it was meant to be wavy & also to use a lot of flex agent in the paint. He used filler and, as I expected, it's since sunk (or the paint on it has) so can be seen, plus he seems to have scrimped on the flex agent as small cracks have appeared on the corners. I would be extremely angry about wasting 3 days on the preparation, but looking at the huge amount of micro blistering that's occured on the (new) lower air dam he did, the bumper cover looks pretty good in comparisson 
Make sure you pick a painter who knows what he's doing, and if he says "Don't tell me how to do my job" when you ask if he'll use the correct primer then walk away. It's a real bummer watching one part of the car you thought you'd finished looking worse and worse as the weeks go by.
Make sure you pick a painter who knows what he's doing, and if he says "Don't tell me how to do my job" when you ask if he'll use the correct primer then walk away. It's a real bummer watching one part of the car you thought you'd finished looking worse and worse as the weeks go by.
