Here are two Instructables in one! Shoot rings of smoke across a room with the Tub Thumping Cannon and the Barking Tube Cannon. Watch me build them and the test results. From MAKE MAGAZINE Volume 15
Step 1: Tub Thumping Cannon
This one is so easy to make and gives great results. You will need a fog machine to generate the rings for both of these projects.
What You Need...
1. 32 Gallon Plastic Trash Can
2. Heavy Duty Trash Bag
3. Golf Ball
4. 2 Bunjee Cords
6. Box cutter.
Step 2: Build it...
1. Using the box cutter, cut out a 6" hole in the bottom of the trash can. Many trash cans have re-rounded circles you can use as guides.
2. Cut out a piece of trash bag a little bit larger than the top of the trash can. Roll up the golf ball in the middle of the bag and secure it with a small bunjee cord. Run a longer bungee cord through the smaller cord.
3. Secure the trash bag to the trash can using tape and attach the longer bunjee cord strap ends to the trash can handles.
Step 3: Use it...
Fill your new Vortex Cannon with smoke, pull back on the bungee/ball handle and let it rip! You should get a nice ring of smoke that shoots across the room. Try a larger hole in the trash can for a larger ring. You've just built the Tub Thumping Cannon! Now on to the Barking Tub Cannon...
Step 4: The Barking Tube Cannon
This Vortex Cannon uses sound waves to generate the smoke rings. This concept was inspired by Bill Beatty
What You Need...
1. 12" cardboard concrete form tube available at home improvement stores.
2. 12" Woofer/Speaker
3. Thin piece of plywood
4. Cutting tool to cut a circle and tape.
5. Audio amplifier and laptop
6. Tone Generating Software