TIG welding differs from conventional electrode and CO welding mainly in that the welder welds with a tungsten non-melting electrode and has to use both hands. With one hand, the welder holds the torch that produces the electric arc and in the other hand the filler material that melts when it meets the arc and produces the weld. It is because the welder needs both hands that the TIG welding method is one of the most complex welding methods (in terms of learning but also in terms of use). However, it is also one of the most versatile welding methods and when done correctly the highest quality welds are achieved. This method is used when welding non-standard materials or where very precise and small welds must be achieved.