Halloween is ALL about the accessories, that extra little detail is the key to get the reaction you are looking for. We chose a Pirate theme this year and needed a little something to give the decor that extra punch. I created a smoke cannon using a classic design and dressed it up to resemble a ship's cannon. The result is a lightweight and fun accessory for kids and parents alike.

A smoke (or vortex) cannon is basically a vessel with a hole at one end (usually close to half the diameter of the side) and a diaphragm at the other end. When the diaphragm is punched, air shoots out of the hole; but due to the circular lip the air forms a toroid (doughnut) of air which travels great distances before petering out. Add a little smoke or fog and you get a very cool effect. There are a few great instructables out there on how to make one of these cannons; the business end of my cannon is basically a copy of Steve Spangler's design as seen on Ellen.

PIRATECOVER2.tif
Download

Step 1: ITEMS and EQUIPMENT

For this instructable you will need the following:

Plastic Garbage can. In my case it is a "Rubbermaid Animal Stopper" which is complete misnomer because squirrels chewed through the lid in the first week. This made it a perfect candidate for this project!
Plastic sheeting, shower curtain, garbage bag, piece of nylon. Really, anything that will hold air.
Box tape, I used hockey sock tape as well.
2 Black poster boards (aka bristol board in Canada).
4 times 3 foot lengths of 3/8" foam pipe insulation.
≈ 4 foot by 4 foot of scrap plywood or strandboard.
3 foot length of 2x4 or 2x6.
Fog maker, I bought mine specifically for this project for 40$.
6 times 1.5 inch screws
Matte Black spray paint

You will also need these tools:

Hand drill
Jig saw
Glue gun

Step 2: HOLE CUT

From my research the typical hole is about half the diameter of the front face of the cylinder (or box). In hindsight I should have made my opening a little bigger because I have seen some examples at 2/3 the diameter working very well. I used some glass bowls and a pencil to trace the circle to guide the cut. I tried using the utility knife to make the hole, but plastic was (surprisingly) too thick. I then drilled a pilot hole and made quick work of it with a jigsaw.

Step 3: DIAPHRAGM

Not THAT diaphragm, I looked for another term , and thesaurus.com was definitely no help. I don't know a more appropriate name for it; it's a flexible air-proof barrier which allows you to increase the pressure in the vessel (like the diaphragm in your rib cage that forces air in and out of your lungs).

First, drape the plastic over the opening of the garbage can, and trim the excess all the way around to leave a few inches. Then take strips of tape and fasten it down along the edge; I used hockey sock tape which has a little elasticity in it. After I had pulled the plastic relatively taught, I put a strip around the top edge. Alternatively you can use a bungee cord around the circumference (don't cut the plastic as short in that case).

If your goal is to make a Vortex or Smoke Cannon, congratulations it's complete! Just fill with smoke and slap the plastic to get the rings to fly across the room.

Step 4: LENGTHEN THE CANNON

The garbage can alone is a little stumpy as ship's cannon go; so we need to give it some stretch. I used two pieces of black poster board wrapped around the snout. An extra set of hands is recommended for this step, I didn't bother and ended up with a slightly turned up snout... I used box tape to make a shallow angled cone and then taped it into place.

Step 5: THE BASE

To keep the cannon off the ground and provide some flexibility in aiming I built a very simple stand. The shape of the end pieces were already cut in the pie shape from a failed project (GIANT smoke ring cannon). These were the perfect size and the geometry provides an easy height adjustment by rocking the cannon forward or backward. To assemble the base I merely put two 1.5 inch screws in through the strand board (aspenite) and into the end of the 2 foot long 2" x 6". Make sure to test different position of the canon so that it is well balanced before securing it. I taped the cannon into place by forming a figure eight around the garbage can and the 2" by 6", and I added a screw on each side (at the top of the peak through the strand board and garbage can) to secure it into place.

Step 6: FINISHING TOUCHES

To give the cannon that authentic look I needed to add some ribbing; particularly around the mouth. After considering many options I settled on foam pipe insulating sleeves. These are very inexpensive (0.80$ for a 3 foot length) and easy to work with. They are already split longitudinally along one side. Sticking a utility knife into the gap and cutting the other side to make two equal halves was easier than expected. I used a glue gun to fasten the ribbing to the cannon; use a lower temperature setting if you have the option because the glue was melting and sinking into the foam after it got warmed up.

I used up an entire can of the matte black paint, and I could have used a bit more for touch ups. Matte (as opposed to glossy) is best in this case because it hides imperfections and hides the fact that you have many different textures (foam, textured plastic, glossy tape, strand board).

Step 7: FIRE AT WILL!!!!

That's it! Fill the hole with smoke or fog and tap the back. Softer taps create longer lasting slow moving rings. Hard punches will give a bigger puff at the receiving end.

My kids love it when we take out the cannon to fire a few rounds. If you have two cannons you could play a game of knock over the opposing "ship's" stack of cups.