A 17-year-old named Sagar has created a 3D printer capable of printing in metal. Currently it is restricted to using solder, but he plans on experimenting with different materials, and eventually releasing an extruder on Kickstarter for around $150. The extruder would be able to handle the process of extruding metal filament. While this is a long way off from allow us to print in a large variety of metals, hopefully with some material engineering we will one day see more options become available. Read more about Sagars printer at: http://3dprint.com/5737/affordable-metal-3d-printer/