A couple of helmets made using 2mm EVA foam, glued with contact adhesive and painted with acrylics.
The shapes were first cut out in paper, then transferred to the foam. The pieces are glued using contact adhesive applied to both edges, then several layers of thinned PVA is painted on to fill the texture. Rivets are made from latex blobs applied with a cocktail stick. Finally painting is done with acrylics, using the silver as an applied sheen.