Pairadocs did an awesome full-blown movie Transformers repaint… protoform verion of Optimus Prime.
he writes:
Several layers of metallics here – first a metallic black base, then layered drybrushes of Oily Steel, Silver, and a custom mixed metallic light blue. Then accent colors were added in. All screw holes were filled in and sculpted to keep the figure one solid piece with no distractions.
Very nice job!
More images here.