Arc spray (sometimes referred to as twin wire arc spray) is a process that uses an electric arc to melt wires. The systems push or pull two wires to the gun to be sprayed. The wires are forced together and form an electric arc, melting the wire. Compressed air passes through a nozzle which atomises the molten metal and sprays it onto the work piece. These wires are interchangeable and can be used as one wire zinc, one wire aluminium for example. The higher the current rating of the system, the higher the spray rate. Coatings of zinc, aluminium, steels, copper, bronze and other materials can be sprayed for corrosion protection, engineering reclamation, surface modification and decoration.
Anti-corrosion and engineering coatings can be applied using the arc spray process. Changing between anti-corrosion and engineering wires is quite simple. Arc spray systems are commonly considered to be easy to operate and to automate and are offered as "push" or "push/pull" systems. A "push" system pushes the wire to the gun, is lighter and easier to use than a "push/pull" gun and is generally used for engineering applications which use hard engineering wires and have a shorter distance from the machine to the gun (5 metres). "Push/pull" systems are used when a longer distance from the gun to the machine is needed and are typical for anti-corrosion jobs that use soft wires (zinc and aluminium).