This process is basically the spraying of molten material onto a surface to provide a coating. Material in powder form is melted in a flame ( oxy-acetylene or hydrogen most common) to form a fine spray. When the spray contacts the prepared surface of a substrate material, the fine molten droplets rapidly solidify forming a coating.
Flame spray, also known as oxy/ acetylene combustion spray is the original thermal spray technique developed nearly 90 years ago. It uses the basic principles of a welding torch with the addition of a high velocity air stream to propel molten particles onto the substrate.