Electric arc spraying utilises wire feedstock to produce strong, adherent coatings for a wide range of industrial applications. Coating properties are controlled by the feedstock material and spraying parameters, and care must be exercised in specifying properties since sprayed deposits are inherently quite different metallurgically from more commonly experienced wrought or cast products. The significance of coating adhesion and the problems of its measurement are discussed together with other important coating properties such as hardness and residual stress. The causes of compositional changes during spraying are indicated and their significance discussed. Applications of arc spraying range from large steel mill or papermaking rolls to tiny electronics resistors and although any electrically conductive wire can be sprayed, most applications are satisfied by carbon steels, stainless steels, bronzes, copper, zinc and aluminium. Almost any material can be sprayed onto and, depending on choice of material selection and component size, coatings may range up to 75 mm thick. The arc spray process offers significant cost savings over other coating processes but it is usually selected on technical merit and on overall product cost savings.