Homemade musical-instrument costumes can make for a creative ensemble suitable for adults and children alike. The majority of the items used in crafting the costumes can be found in your own home or with a few small purchases from a local craft store. These costumes can be strong competitors at costume competitions due to their individuality. You will not be likely to run into duplicates at costume parties.
For a piano or keyboard costume, choose a box that is wide enough to fit comfortably over your torso but long enough to cover your shoulders to your thighs.
Remove the bottom flaps from the box and create a hole in the top to fit your head through, but not so wide that the box will slip past your shoulders. Create holes in the sides for the arms to fit through. Using white paint, draw and color in piano keys going lengthwise down the rectangle. Paint the rest of the box, surrounding the white keys, black as well.
Either paint the black keys on top of the white, or for a 3-D effect, paint a series of jewelry or matchstick boxes black and glue them to the white keys. Since this costume will be a challenge to sit on, it is advisable to wear black clothing underneath it so the costume can be easily removed.
To create a drum, choose a large, square box that can sit comfortably over the torso. Remove the bottom flaps and cut holes for the head and arms in the top and the sides.
Using poster board that is cut to the same width of the box, glue the edges of one piece to the front-left and back-left edges. Do not press it flat to the side of the box, but arch it from edge to edge, giving the square box a rounded corner. Repeat this process with the opposite side. The shape of the box should now be between an oval and circle.
Paint the poster board and visible front and back sides of the box to give the separate pieces uniformity. Once the base coat is dry, go back and add details. Since the arched poster board will create gaps visible from above between the poster board and the actual box, they will need to be covered. Use wrapping paper to cover the entire top of the box, all the way to the edge of the poster board. However, refrain from covering the hole for the head.
Carry drum sticks or chop sticks to play the top and side of your drum as you socialize at the costume party.