I've had pretty good success using silver metallic sewing thread:
It comes in several different diameters and colors - silver, gold, and black. It's made of a metallic colored mylar-like material wound around a core of thread. It's very flexible, but will not hold a bend by itself like wire or lead solder.
However, once painted it looks very good - a little dry-brushing will bring out the texture.
You can find this stuff in the sewing notions sections of large crafts stores and places that sell fabrics, etc.