Manual metal arc welding

An electric current (either alternating current or direct current) is used to form an arc between an electrode coated in flux and the metals to be joined.

The flux gives off gases to prevent oxygen reacting with the weld metal. The flux then solidifies to form slag on top of the weld. Once cool the slag can easily be chipped off.

MMA welding takes a lot of manual dexterity in order to be able to make good welds. Flat welds are easiest, but skilled welders can do vertical of overhead welding. The most skilled welders undertake joints in high pressure pipes which require a continuous transition between the various welding techniques.