Now NASA is 3D printing with Copper. That's right! They have successfully 3D printed a copper combustion chamber liner which will eventually be tested in live conditions. Using a high powered selective metal sintering machine, they printed the part in over 8,000 individual layers, taking over 10 days to complete. Next it will be coated with Nickel before being tested to see if it can hold up to the harsh conditions of a real mission. Read and see more at: http://3dprint.com/59881/nasa-3d-prints-copper-rocket/