I bought a styrofoam head for my new "Rotting Ralph" mask today but the mask is so huge! How do you guys add mass to a styrofoam head? It doesn't matter the end result of the head because it will be inside the mask.
Cover the head completely with single sheets of newspaper and masking tape, then slap on Celluclay - you can buy it at Wal-Mart, Michael's, Hobby Lobby.
Or, you could just tape tons of paper to it, but you'd likely lose some dimensions and shape.