I'm repainting my prelude. I've got the entire car sanded down (car was the victim of a crappy single stage paint job by the previous owner) and primed. The bumpers are the factory urethane, sanded down and sprayed with adhesion promoter and flexible primer. I've got the flexible primer sanded smooth, and in some places it is really thin where you can see the urethane is right at the surface.

I've got a BC/CC from Dupont ready to go on, my question is do I need to spray adhesion promoter on the bumper again before i spray my basecoat? Or would that be a dumb idea?

Another question: even without a flex additive in the paint, should i worry about the paint falling off due to bumper flex/expansion? The man at the paint store said it should not be a problem. This is not the cheapest paint by far. I think it is their Chromasystem @ $150/quart.

Thanks in advance.

 

Adhesion promoter never hurts. If you can see through the primer to the urethane you should apply another coat. Flex additive is a must in the primer and in the clear on the bumper covers.

 

OK thanks for the info. I'll go back to the paint store and see about getting a flex additive. I've spent so much time on prepping this car I don't want to mess it up here at the end.

 

I actually just talked to my paint store about this recently. The flex-additives are only temporary, as in they actually evaporate out of the paint in a small amount of time. He said they were created so bumpers could be painted off of cars and then installed without the paint cracking. And it is really just made for cars with huge flimsy bumpers, so you should be fine without it especially if you are painting the car with the bumpers on (don't know if you are or not).

 

Thanks for the reply. The whole car is stripped so I'm painting off-car, but I don't think it will take much in the way of flexing the bumpers to get them back on. According to Dupont, their BC is already flexible, and their CC is somewhat as well (especially when freshly painted). But they still make the flex additive for it.

I went back to my paint guy and he swore that based on his experience I wouldn't need any additives, and I trust him so I'll go with that. As far as the rest of the people on the internet, I've read many, many forums and they are split evenly on this issue.

Another question: Any reason to think spraying adhesion promoter before BC but on top of primer might interfere with color?

 

You wouldn't need any adhesion promoter on primer...shouldn't hurt though, it's made to go under paint

 

Yeah I have the tendency to overthink things.. But then I'm not going to get another chance at doing this car again any time soon so it has to work. Or look like crap when the paint falls off. Either way, I bought it

 

look into spraying a sealer. that goes on top of primer be4 the basecoat i believe... helps prevent bleed thru. of the color/primer underneath

 

Thanks for the suggestion. I am using a compatible primer though, so I don't think it is necessary. The car has already been sanded past the previous paint job and primered completely, so I do not see any possibility of bleed though.