I am writing a basic specification for procuring parts that are to be powder coated with a semi-gloss black. I am having a difficult time defining the quality of the finish. That is how the part looks. This is beyond describing the level of gloss. The finish is to be smooth but is there a way of defining acceptable levels of visual defects? M. R.
The Powder Coating Institute in Alexandria, Virginia has “smoothness standards” that can be just the thing for you. They have a scale from 1 to 10 that is used to rate the smoothness of a powder coating surface. You can purchase these test panels, in an attractive case, from them directly. Visually evaluate which panel has the surface smoothness you want and note the number on the back. Write the following statement in your coating services specifications: “Smoothness in accordance with PCI smoothness standard #___.” That should take care of it.