I made covers/masks from thin vacuum formed styrene plastic.

The entire thing was hand sculpted originally. Even the eyeballs. They are slightly different in shape from each other. So I wanted to be sure in the orientation. 😁

It's a photographic chemical process. Positive image is laid down on the metal. Then submerged in an acid bath. U protected areas are eaten away. Rinse and use. Many metals can be etch, partly or all the way through.

I start with Tamiya fine primer. Then I airbrush with Golden Brand and Winsor & Newton liquid acrylics. Layer by layer. I build it up and go back and redo areas. Takes a bit of time, but the results are worth it.