How should hinges be prepard before spraying? I found a company that can spray 95% composite metal and now I´m thinking about a first project. Their coating description: 1) Composite Metal: plus 70 -150μm 2) Treatment: minus 20 - 60μm 3) Clear Coating if wanted: plus 80μm (depends on kind of metal - 24K, copper, stainless, alu ...) In the worst case the material increment is about 210 μm. The question is: Should I grind the inner parts of the hinges and they can coat the whole thing or should I leave these parts in the original color? Any artists here sharing their experiences?