Hold a sheet of newspaper up to the front of your body and have someone draw in the contours of your shoulders to armpits, your chest and down to your waist. The armor can be decorated after the papier-mache process to fit the style of the movie, so begin with a basic shape.
Cut out the pattern and lay it on a sheet of cardboard. Trace around the outline and cut it out. To flare the waist, cut into the bottom 2 to 3 inches, every two inches. Pull the tabs outward and secure with masking tape. The seams need to be as smooth as possible. Repeat the process for the back of the armor.
Tape the front and back of the armor together with masking tape. Turn the armor upside down and gently tuck a garbage bag into the neck and armholes. Fill the body with crumbled newspaper to help the cardboard retain its shape while the papier-mache is applied.
Fill a large bowl with a few cups of flour. Slowly add the water and mix with a wooden spoon until it's the consistency of white glue. The mixture varies by preference, as it needs to be easy for you to work with. If you find you've made the paste too thick, add some more water and stir. If it's too thin, add some more flour to thicken.
Tear or cut sheets of newspaper into strips that are 1 to 2 inches wide and 4 to 8 inches long. This is based on preference; trim the sheets into shorter lengths if you find yourself having a difficult time keeping the strips smooth during the application.
Dip the strips one at a time into the flour mixture. The strip needs to be completely saturated. Hold it by your index finger and thumb of your dominate hand and gently squeeze it between your middle and index finger of your other hand, dragging down to remove excess liquid.
Lay the strips lengthwise along the front and back of the cardboard armor. The strips should overlap each other, while remaining smooth. The first layer is finished when the cardboard is completely covered. Allow the first layer to dry. This can take a few days. Repeat the process two to three times until it's sturdy.
Trim away any excess papier-mache and gently cut away the front from the back. Attach a hook and loop fastener strip to each shoulder and two for each side.
Attach any details along the surface, such as beading along the trim. Spray paint the entire surface using one color or a combination of black, silver and gold paint to create the desired effect. Allow it to dry completely before removing the inside stuffing.
Wrap a ribbon around your forehead to the back of your head. Cut a small line in the ribbon to mark it. Blow up the balloon and use the ribbon to measure it to the size of your head. When it's the right size, blow into the balloon one or two more times more to allow for shrinkage during the papier-mache application.
Tie a knot at the bottom and press it into a funnel. Insert the funnel into the oatmeal canister and tape the edge to the canister to secure. Cut a cardboard cereal box into the desired shape and tape it to the balloon. The cardboard should fit snugly against the balloon.
Combine flour and water into a mixing bowl to form a paste. Cut newspaper into strips that are 1 to 2 inches wide and 4 to 8 inches long.
Dip each strip into the paste to saturate. Hold the corner with your dominate index finger and thumb and squeeze off the excess paste with the middle and index finger of your opposite hand. Apply each strip to the cardboard box beginning at the crest. Each strip should overlap the previous strip, while remaining smooth.
Continue the application until you have covered the entire surface of the cardboard. Allow it to completely dry before adding the next two layers.
Remove the funnel from the canister and pop the balloon when the application is completed. Cut away any excess papier-mache to make the edges smooth.
Design the exterior of the helmet to match the era of the movie. For example, a small container on the top of the helmet is ideal for added plumage. Spray paint the exterior to match the chest armor. Allow to dry before use.