Twin-wire arc spray metallised coatings are the most versatile coatings used in industry today. The arc spray systems are considered the work-horse of all spray systems. As the name suggests, these systems work by arcing two wires against each other, and using compressed air to propel the molten metal onto the work surface. The most common applications for these systems include dimensional restoration of rotating equipment, such as journal rebuilds. These systems are also commonly used for large-scale hardfacing applications, particularly for jobs which need to be performed in-situ, such as large vessel protection and boiler tubes hardfacing.