EVA Foam — The Accessible Standard
EVA foam is the entry point for most cosplay armour builders — inexpensive, widely available, easy to cut and heat-shape, and lightweight to wear all day. Its limitation is surface quality: raw EVA always looks like foam without sealing and finishing work. For large, simple armour pieces (pauldrons, breastplates, greaves), EVA is often the best choice because the scale makes detailed surface work less critical and the lightweight is valuable.
Worbla — For Detail and Durability
Worbla is significantly more expensive than EVA foam but produces a harder, more detail-capable surface. It's particularly useful for pieces that need to hold fine detail — raised decorative elements, precise edges, or areas that need to withstand physical contact without denting. The standard approach combines both: EVA foam for the core shape (cheaper, lighter), Worbla applied over the top for surface quality and detail.
Foam Clay — For Organic Forms
Foam clay (a lightweight air-dry clay with foam particles) is ideal for organic, sculptural shapes — creature features, textured surfaces, and forms that are difficult to achieve by cutting and shaping flat sheet materials. It can be applied over EVA armatures, sculpted while wet, and sanded and painted when dry. Its limitation is brittleness if thin — it works best at 5mm or more thickness.
The Verdict
Most complex cosplay armour uses all three materials in different applications within the same costume. Choose the material for each part based on what that part needs: lightweight large pieces in EVA, detailed surface work in Worbla over EVA, sculptural organic elements in foam clay.