Making yourself a model of a prosthetic arm, whether for the purposes of education, a costume or just for fun, is easy and can be accomplished with a few commonly-found materials. Paper mache is a great material to use when making models of body parts as it is flexible until it dries so you can easily correct and modify the model until it is just he way you want it. You can also paint the model to look more realistic later on.
Things You'll Need
2 cups flour
2 cups water
1 tsp salt
2 Paper towel tubes
Wire coat hanger
Tape the ends of your two paper towel tubes to the tennis ball to form a frame for the arm. Make the angle between the two tubes the angle you want the model arm to have.
Wrap some newspaper around the paper tubes to mold and shape the form of the prosthetic arm. Secure the newspaper in place using some masking tape. Round off the wrist where you will later add a hook in place of the hand.
Cut an 8-inch section of wire from a wire coat hanger and shape it into a hook. Insert the opposite end of the hook into the newspaper and paper-tube arm frame, and wrap with a thin strip of newspaper secured in place with some tape to bulk up the wire hook.
Prepare your paper mache mixture. Mix together the flour, water and salt, and stir. You should have a mixture with the same consistency as paint. Tear some newspaper into 2-inch wide strips.
Coat the newspaper strips in the paper mache mixture and then wrap them around your arm and hook model. Add enough layers of newspaper until you have a form that closely resembles an arm.
Allow a day for the model to dry, then paint the body of the arm and the hook for realism, if you wish.
Wipe off excess paper mache mixture from the strips of newspaper before applying them to the model. Sandpaper can be used after the model hardens to smooth the surface of the arm.