DID YOU KNOW THAT THE PLASTIC FROM 2 LITER SODA BOTTLES CAN BE TURNED INTO BANJO HEADS? That's exactly what Jack Bower did with this three string dulcimer/banjo instrument.
He started with a plywood body, roughly six inches wide and thirteen inches long. The dimensions were determined by the maximum amount of area a pop bottle would have once the plastic was cut, laid flat and heat-shrunk with a heat gun.
By heating the plastic, it thickens it and makes it tight enough to hold tension. Once he got it shrunk enough, he tacked it to the open body using small brad nails. Another heat treatment tightened the head even more.
The neck is a combination of oak, walnut and mahogany and it's fretted in a 22" diatonic dulcimer scale. Check out the wild headstock design with side mounted tuners.
He made sure to sign and number it, too!
The dulcimer strings are anchored with removable screws and the bridge is a hand carved floating bridge. Notice how he made the bridge almost three inches long in order to cover as much area on the pop bottle head, evenly distributing string tension.