Ancient Greek helmets have a classic, immediately recognisable design. Some helmets, typically those belonging to an officer or person of rank, often sported a crested plume. Kids can make simple helmets for play that recall the movies "The 300" or "Troy" with just a few household items and materials commonly found at hobby and craft stores.
A Very Simple Helmet
For an extremely simple helmet, use a cardboard box that fits over your head. Cut out a face opening that is classic for the helmet design. Go on the Internet or look at images of Greek helmets in books to get an idea of classic designs. Cut the back so it follows the back of your neck, leaving the sides long, almost like hanging dog ears. Paint the helmet box with bronze metallic paint.
An Improved Helmet
Make your helmet with cardboard, paper mache and an old baseball cap. Cut off the bill from the ball cap. Tape cardboard extensions around the back and down the sides of the cap to create the back and sides of the helmet. Use smaller pieces of cardboard along the front of the cap to make an extension just above the eyes. The result should be roughly the design of a Greek helmet. Cover this base with paper mache. Note: make the base larger than you need because the overall size will become smaller with the layers of paper mache. Cover both sides (inside and out) with paper mache. Once it's dry, paint your helmet with metallic paint.
Add a Plumed Crest
For your paper mache helmet, you can make a plumed crest. Cut out two curved rectangular shapes out of cardboard that will fit along the top curve of your helmet. These are the sides for holding the crest. Cut out two smaller squares for the ends of these sides, creating a curving box. Glue them together, cover with paper mache and paint to match your helmet. Glue the box onto the top of your helmet. Using more glue, fill in the box with craft feathers until you have a full, feathered plume.