Endura bumper paint crack
 

I just painted my 69 GTO and when installing the front endura bumper, I accidentally cracked the paint in an area on top of the bumper. It was completely my fault as I got too rough with it trying to adjust it. It’s a very small area about 1 inch long on top of the bumper. I hate to sand the whole bumper down to repair this small area. It there a way to fix this or is sanding the whole bumper down and re-shooting base/clear my only option? The paint is less than a week old. Thanks

The right way is to blend the base and clear the whole bumper. You can blend the clear but you will eventually see the edge. I'd clear it all.

Geesh! On my 72 endura I was pushing and pulling my ends to get a better alignment and it never affected the paint at ll. I was worried about cracking the paint, because I was flexing the ends pretty good. Not sure if you used SPI epoxy for primer. If not, that is the base of your problem. You will also always have more issues down the road. If it were mine, I'd be sanding down to the rubber and doing it right. Once and for all.

I don't see a crack. To me it looks as if the paint lost adhesion in that spot, either from stretching while handling it or rubbing the edge against something and maybe you pressed the paint back down afterwards? If that's correct, we can work on a solution.

It's all speculation until we know your prep process and materials that lie beneath the color. I looked at the temps in Oklahoma last week highs in the 80s and lows down as far as 61. If you used a high temp hardener, the low temps at night would play havic in the curing process, so it may not have been fully cured when you installed it.

I painted the bumper 2 days ago. So, I probably jumped the gun on installing it. It was about 75 degrees when I was painting that morning and I used a mid temp hardener. Was up in the 80’s that afternoon as the base/clear dried. I took the bumper down to the rubber and used an epoxy based primer on it. I then used a flex additive in my base coat/clear coat. I should have left it alone but the bumper was too close to the top of the fender for my liking so I grabbed that area and kind of pulled down on the bumper as I tightened the bumper bracket bolt. The adhesion seems to be fine everywhere except the line that was formed by me adjusting the bumper.

Looks like it wrinkled ....we’re you using a heat gun on it ?

Any way ...like noted above ....scuff the whole bumper by hand with 800 grit...

Block sand with 600 wet and get to the root of that area...probably sand a feather down to the epoxy.

Recoat that spot with 2-3 coats of epoxy

Sand that epoxy the next day

Coat entire cover with DBC 500 ..one coat

Spot in with base color

Clear coat entire cover

One thing many of us have learned from others mistakes is, regular epoxy doesn't flex well on these rubber bumpers like the SPI does. We also don't use flex agents in our paint, as they aren't needed. On my 72, I was literally moving my ends in several directions at least 1/4" and have no cracks or anything with six coats of base and three clear (this is a tri coat paint).
If I see your pics correctly, it looks like the leading edge has chips also.

I've been using PPG DP epoxies with great success on these bumpers for years. Even though SPI is obviously a great product, I don't believe SPI has this market cornered.

I havent ever tried any other Epoxy on endura material but the spi so I cant speak for the affectiveness of other brands of epoxy, I can say I can severly flex my 69 bumper and it doesnt crack. My bumper was in fairly nice shape to begin with needing only minor repairs with 3m.