63 Dart bezels and 3D printing?

My experience is the material needs to be temp and humidity resistant. I had a part in the trunk of my car and one day in the sun and it was warped all out of shape

Wish I could give you some materials help, but I'm in the dark on that

I do know there are some materials that have a metal component to them

Maybe you just need to fill them with epoxy or fiberglass resin. I would coat the inside before doing this with aluminum foil or something. just a thought.