I bought a bumper from the junk yard of a 84 camaro. The bumper looks to be in nice shape but had spider cracks in the paint so I was going to take it all the way to the urethane. It has many coats of paint on it! But when I got down to what I am guessing is the yellow urethane, I can still see the spider cracks! Are these in the bumper itself? If so can I still use it if I use adhesion promoter and epoxy primer? I don't have money to buy another one!

 

Theyre in the bumper for good if you can still see them. I Just trashed my original one a few months ago and bought a new one. You can use filler and then buy a protectant that goes on before paint that doesn't stretch when the sun hits it. But they'll just come back in time if you keep this one.

 

Can you see the cracks fom the backside? If not, they aren't all the way through. Even if they are, you could grind out small sections and repair with plastic repair goop. I don't think spider cracks will spread much in these bumpers unless the bumper is flexed hard like it was when they were created. You can certainly fix it.

 

Are the spider cracks throughout the (I'm assuming its the front bumper cover/clip )or are they in a isolated spot.

 

They do not go through to the back. I tried sanding them out but they seem pretty deep and the whole bumper is covered in them at least in the paint. And on top of that I counted 12 coats of primer and paint! Two coats of tan, gray, blue, brown and black all with a layer of primer between them. So I gave up on it and started working on my old bumper cover that was in a wreck. I didn't want to use it because it has some slight waves and a small tear but I don't want to spend any more money since I don't think junk yards have a return policy. Another 75 bucks down the drain.

By the way does bondo work with bumper covers well if you keep it thin?

 

bondo isnt flexible so dont use it on bumpers

 

Sounds like that bumper has seen a lot of stress. Strange that none of it shows on the back.
No, bonds won't work but there are flexible fillers. You can fix it, but if it's that extensive, maybe you would be better off with a better bumper.

 

Ok I found the poly filler. My next question is the primer. I have kustom shops 2k primer and epoxy primer. For the body I was going to use adhesion promoter-epoxy primer - 2k primer - reduced epoxy primer for sealer- bc cc. What should I do with the bumpers? Just epoxy? Just 2k? Straight to bc? Thanks!

 

2k will be fine. Everyone will try and tell you to use flex additive. I have painted many bumpers some with and some without and never had a need for it. I feel personally that the paint comes out nicer with out flex in it.

You can make the decision on flex but in my personal opinion make sure you use adhesion promoter. Bully dog is great stuff, cheap and goes a long way with ensuring good long term adhesion on urethane, abs, and other plastics.

 

Thanks that is helpful!