MMA (cont.)
The arc melts the electrode and parent metal to form the weld pool
The pool is protected from the atmosphere by a liquid slag and gas formed by the melting and vapourisation of the flux covering
The welder must simultaneously move the electrode along the work to traverse the arc and towards it to maintain the arc at the same length
The slag formed adheres to the deposit protecting it as it cools - it must be chipped away after each weld pass