Mark the first tank at the bottom where the scuba tank starts to get round, marking each tank sequentially 2 inches shorter. Cut old tanks on marked lines and file the edges. Tie a knot in the end of a nylon rope so it will not pass through the hole at the top of the tank. The rope should extend 2.5 feet from the top of the old tank.
Take a piece of nylon rope 5-feet long and tie a knot 16 inches from the bottom. Take one of the scuba tank bottoms and grind the edges safe to the touch. In the center of the old tank bottom, drill a hole. Insert a piece of all-thread rod in the hole and put a washer and nut on each end, leaving at least one half-inch thread exposed. Tighten. Screw an eye nut on each end after the nuts are tightened.
Tie a length of rope onto the eye hook on the round side (bottom) of the bowl. Make the rope long enough so the striker is 6 inches above the bottom of the old tank chimes. On the underside of the striker, tie a rope 12-to 20-inches long. Cut a 12-inch length of 1x6-inch board. Drill a hole 2 inches from the top of the board and in the center. Attach the board to the rope.
To make the hanger for the wind chime, take two pieces of box or C-channel 22- to 24-inches long and form a cross. Fasten with a piece of all-thread through the center holes. On each end put a washer, then a nut, tighten nuts then screw an eye hook on each end.
On each spoke of the cross put a piece of all-thread through the last hole with a washer and nut on the top and bottom and screw an eye hook onto the bottom of each rod. Tie the old tank wind chimes onto the eye hooks at the end of each channel and tie the striker to the center eye hook.