Want to 3D print metal objects on the cheap? Unfortunately, no “consumer-grade” “desktop” 3D printer is capable of doing this… but there is a close compromise that works under some circumstances. Often times, in the case of decorative items, the use of metal serves no essential purpose other than to be shiny in order to make the item in question look pretty. In this case, metal plating of any solid substrate is good enough. And, what better way to metal plate than by electroforming? Just paint a conductive carbon ink coating on the surface of your 3D printed part, place it in a electrolyte bath, run the electric current, swirl it around, and tada! You’ve got a “metal” object, as far as eyes are concerned. To plate with arbitrary metals, first electroform copper, then you can electroplate almost any metal on top of that. So the same could be said… with using a soldering iron to deposit other metals onto the surface of copper, but that is significantly labor intensive for objects of any appreciable size, i.e. anything larger than the size of electrical solder joints.
Another point in hand… if your metal coating is thick enough and the surface area large enough, you could even use metal-plated objects as a reasonable electrical conductor for DIY electronics. In particular, the ne ultra achievement… you could 3D print your own surface board substrate, then metal-plate the conductive traces on top.
Please see my my previous blog article for links to Instructables and more details on how to do this.