Arc Spray

Arc spray is a thermal spray coating process where two electrically conductive metal wires are fed into a gun, melted by an electric arc, and atomized by compressed air. The molten droplets are propelled onto a prepared substrate to build a coating, commonly used to restore worn dimensions or apply wear- and corrosion-resistant layers before finish machining.

On a CNC repair or remanufacturing job, the worn area is first machined to a controlled profile or undercut, then grit blasted to create a mechanical key. The part may be preheated to a specified temperature, and the arc spray gun is traversed at a controlled standoff in multiple passes until the coating reaches a defined build allowance. Because the process deposits metal rapidly with low heat input, it is a practical choice for shafts, feed rolls, and corrosion-worn machine elements that need dimension recovery without distortion. After spraying, the component is sent to a CNC lathe or mill, or to grinding, to bring diameter, runout, and surface finish back to tolerance. This lets the repair match OEM size while preserving the base material’s metallurgy, making arc spray a fast, economical alternative to fusion welding in many maintenance and remanufacturing settings.