Copper filament from the Metal series of 123-3D.ie contains about 80% copper. The filament is based on PLA, but is about three times heavier. 3D printed objects have the look & feel of real metal: they feel cool and sturdy.
3D printing with copper filament is problem-free with both a Direct and Bowden extruder (with retraction and a nozzle of at least 0.35mm). Copper printed objects can be easily reworked, sanded and polished for an even more beautiful look.
Note: Filament with metal particles does not produce a stronger electrically conductive object; but it does give the 3D object a very natural metallic look.
Read more about printing with PLA filament
here.