Surface Finish Options for Die Casting Parts The diecast must have a good surface finish that will promote durability, protection, or aesthetic effect. There are different finishing options you can use for die casting parts. However, choices are based on the size of the cast parts and the alloy you are using. Painting Painting is the most common surface finishing technique ideal for many materials. It can be for further protection or aesthetic purpose. The process involves applying lacquers, paints, or enamel with special consideration for the metal used. Before the addition, clean the surface of the metal to remove impurities such as oil (this also helps in adhesion), add an underlying paint (primer), and the primary paint.