Why EVA Foam
EVA foam (ethylene-vinyl acetate) is the workhorse material of cosplay armour construction — affordable, lightweight, easy to cut and shape, and available in multiple thicknesses from craft stores and online suppliers. A 6mm high-density foam handles most armour applications; 2mm works for thinner accent pieces; 10mm or thicker for substantial structural pieces. The material's biggest limitation is its texture — raw foam looks like foam, and finishing work is required to achieve a convincing surface.
Essential Tools
Cutting: a sharp craft knife and a fresh blade for every significant project — dull blades tear rather than cut. Shaping: a heat gun to curve and form the foam. Bonding: contact cement (Barge, DAP, or similar) for permanent bonds; hot glue for temporary assembly during fitting. Finishing: Plasti-Dip or Flex Seal as a sealer coat; acrylic paints; rub-n-buff for metallics.
Basic Shaping
EVA foam curves when heated. Hold the piece 6–8 inches from the heat gun and move in a consistent pattern — too close or too long will bubble and damage the surface. The foam becomes flexible within 10–15 seconds; press it against a curved form (a ball, your leg, a curved object) and hold until it cools. It will retain the curve. Practice on scraps before working on final pieces.
Sealing and Painting
Unfinished EVA foam absorbs paint like a sponge — you'll use 10x as much paint as necessary and still get a patchy result. Seal first with 2–3 coats of Plasti-Dip, allowing full drying between coats. Sand lightly between coats for a smoother surface. Then prime and paint with acrylics. The sealed surface takes paint efficiently and resists scuffing at conventions.