Dual Sided Adhesive That'll Stick To The Bumper?
 

I'm attaching the side-mount license plate frame, and I bought some 3M Heavy Duty Double Sided Adhesive, but it doesn't seem to want to stick to the bumper or the license plate frame (it barely stick at all to the latter). So, with that said, anyone know some kind of dual-sided adhesive that can withstand holding up a license plate in cold and hot weather (so one for outdoor use, basically), and can stick to plastic and metal? Thanks.

Butyl double sided tape will usually stick to anything and hold up to the elements.

get the 3m trim double sided adhesive. it might be the same as you have already but its what OEM use to help lips and side skirts stay on.

The problem wasn't really that it wouldn't stick to the bumper, it's that nothing could stick to the plastic license plate mount. I put the tape on the plate just to see if I could do everything screwless and it wouldn't hold any better than a post-it.

Make sure to get the 3m double sided tape that says "Super Heavy Duty." I tried the one that said "Heavy Duty" and it was no bueno. I got Super Heavy Duty instead and on the back it specifically states will stick to metal, glass, and plastic.

You need to get some 3M VHB tape.

We've used it at work to hold up like, 100 pound structures to aluminium curtain walls. Stuff is supposed to be like, 3000 psi or something like that. If the surfaces are prepped properly, your bumper will tear off before the plate does.

you need to scuff up the inside of the license plate mount with some sand paper to get a rough surface to help the 3m tape adhere properly.