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Home-brew Blast Cannon

Materials needed:

  • 1 plastic drain pipe, 3 feet long, at least 3 1/2 inches in diameter
  • 1 smaller plastic pipe, about 6 inches long, 2 inches in diameter
  • 1 large lighter, with fluid refills (this gobbles it up!)
  • 1 pipe cap to fit the large pipe, 1 pipe cap to fit the small pipe
  • 5 feet of bellwire
  • 1 SPST rocker switch
  • 16v polaroid pot-a-pulse battery
  • 15v relay (get this at Radio Shack)
  • Electrical Tape
  • One free afternoon


  • Cut the bell wire into three equal pieces, and strip the ends
  • Cut a hole in the side of the large pipe, the same diameter as the small pipe. Thread the hole and one end of the small pipe. they should screw together easily.
  • Take a piece of scrap metal, and bend it into an “L” shape, then attach it to the level on the lighter:

Home-Brew Blast Cannon

Now, every time you pull the ‘trigger’ gas should flow freely from the lighter. You may need to enlarge the ‘gas port’ on your lighter, if you wish to be able to fire more rapidly.

  • Connect two wires to the two posts on the switch
  • Cut two holes in the side of the smaller tube, one for the switch on the bottom, and one for the metal piece on the top. Then, mount the switch in the bottom, running the wires up and out of the top.
  • Mount the lighter/trigger in the top. Now the switch should rock easily, and the trigger should cause the lighter to pour out gas. Re-screw the smaller tube into the larger one, hold down the trigger a bit, let it go, and throw a match in there. If all goes well, you should hear a nice big ‘THUD!’
  • Get a hold of the relay, and take off the top.

Home-Brew Blast Cannons

Connect (1) to one of the wires coming from the switch. Connect (2) to (4), and connect (5) to one side of the battery. Connect the remaining wire from the switch to the other side of the battery. Now you should be able to get the relay to make a little ‘buzzing’ sound when you flip the switch and you should see some tiny little sparks.

  • Now, carefully mount the relay on the inside of the large pipe, towards the back. Screw on the smaller pipe, tape the battery to the side of the cannon barrel (yes, but looks aren’t everything!)
  • You should now be able to let a little gas into the barrel and set it off by flipping the switch.
  • Put the cap on the back end of the large pipe VERY SECURELY. You are now ready for the first trial-run!

To Test:

Put something very, very large into the barrel, just so that it fits ‘just right’. Now, find a strong guy (the recoil will probably knock you on your ass if you aren’t careful!). Put on a shoulderpad, earmuffs, and possibly some other protective clothing (trust me! You are going to need it!). Hold the trigger down for 30 seconds, hold on tight, and hit the switch. With luck and the proper adjustments, you should be able to put a frozed orange through 1/4 or plywood at 25 feet.

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