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In this installment of Intern’s Corner, our brand spankin’ new Make: Labs intern, Daniel Spangler, shares the details (and gives of a video tour) of his badass internal combustion cannon with interchangeable barrels. We haven’t broken it to him yet, but to keep us happy, he’s going to have to help each of us make one. Welcome aboard, Dan! -Gareth

My interest in cannons started back in high school, when an attempt to make a hydrogen converter went horribly wrong, shattering the florescent bulb in my garage and singeing my eyebrows off. After changing my pants, I looked at what was left and thought, “Hmmmmmm…”

The rest is history. I soon cobbled together a suitable cannon-ish device that could propel small 3/4-inch dowels through about five layers of cardboard, and that was fun, but I had to do more — it always had to be bigger, louder, more reliable, and more powerful. So I kept building. I would build some for me, some for friends, and they kept growing in size and complexity… ’til I achieved what you see here.

This is my advance combustion cannon. It utilizes two BBQ piezoelectric igniters to touch off the propane/air mixture inside the 3-foot-long by 4-inch-diameter combustion chamber. A special metering system using an air regulator, two ball valves, and a specific length of steel pipe ensures that the correct amount of fuel is injected into the combustion chamber. You operate it by tuning the regulator to the specified 90 psi, opening the first ball valve to allow the steel pipe to be pressurized, then after closing the first valve, you open the second one to discharge the gas in the steel pipe into the combustion chamber. From there, a computer fan mounted inside the combustion chamber mixes the air and fuel to create clean, thorough combustion. I have two interchangeable barrels for this cannon. One is a sleeved 3-inch barrel that’s perfect for shooting soda cans, the other is a 6-foot-long 2 1/2-inch bore barrel that launches tennis balls far enough so you can’t see where they land. This cannon is really fun. It fires almost every time, and shooting empty cans is a safe and entertaining way to show it off.

Now you may be wondering, “What’s your next step?” Well, I have been working on plans for a multi-barrel, belt-fed, fully automatic gatling cannon that utilizes a special spud-gun cannon shell that I’ve designed. I haven’t really gone anywhere with it since i didn’t have the funds for the tools, but now that I’ve joined the ranks of the Make: Labs Engineering Interns, anything is possible. We shall see…

[Photo by Gregory Hayes]

Dan Spangler

Dan Spangler

Dan Spangler is a freelance maker with a passion for fabricating speed, high voltage, and the things that go boom.


  • Anonymous

    Impressive rig!  I have had ignition troubles with my spud guns and would love to see your ignition system for this beast.   Now that you are working for make, when can we expect to see this featured as an article in the magazine or at the very least as an instructable? 

    Also look forward to your belt-fed creation in the future!

  • roland stolfa

    Man I want one!  WAY Cool…but what was in the can that made the big explosion on the first video above?  Was it just the propane that was “left” in the can as it exited the barrel?

    • http://pulse.yahoo.com/_BNZPTDRUKTULWLJSYXD3TN7N6E Eina r K

      Very creative video editing made the tree blow up..

    • http://pulse.yahoo.com/_BNZPTDRUKTULWLJSYXD3TN7N6E Eina r K

      Very creative video editing made the tree blow up..

  • roland stolfa

    Man I want one!  WAY Cool…but what was in the can that made the big explosion on the first video above?  Was it just the propane that was “left” in the can as it exited the barrel?

  • roland stolfa

    Way COOL!  I want one….but what was in the can that exploded so nicely at the end of the first video?  Was it just the propane left in the can?

    • http://profiles.google.com/jmsaltzman Jeff Saltzman

      Methinks those were effects of the “special” variety ;)

    • http://profiles.google.com/jmsaltzman Jeff Saltzman

      Methinks those were effects of the “special” variety ;)

      • http://pulse.yahoo.com/_BYHC4RSPU2QLVZS6UX4GQ7NR7M AllanA

        Methinks two……..

        But why?

        • Anonymous

          Um… fun?

  • roland stolfa

    Way COOL!  I want one….but what was in the can that exploded so nicely at the end of the first video?  Was it just the propane left in the can?

  • http://www.facebook.com/thharris Thomas Harris

    fun untill the pvc explodes in your face

  • Anonymous

    Brushless fan, I hope?

    It’s black.  So, does that mean you have located a source for solid ABS pipe and fixtures?  Can’t find the stuff here in the Northeast US. The best I could do was DWV only (not pressure rated).  Any suggestions?

  • Anonymous

    Brushless fan, I hope?

    It’s black.  So, does that mean you have located a source for solid ABS pipe and fixtures?  Can’t find the stuff here in the Northeast US. The best I could do was DWV only (not pressure rated).  Any suggestions?

  • http://pulse.yahoo.com/_BNZPTDRUKTULWLJSYXD3TN7N6E Eina r K

    CGI and bullshit

    • http://pulse.yahoo.com/_BNZPTDRUKTULWLJSYXD3TN7N6E Eina r K

      By that, I mean that the tree exploding with a fireball is not real.

      Have no problem with the spud gun itself.

  • http://pulse.yahoo.com/_BNZPTDRUKTULWLJSYXD3TN7N6E Eina r K

    CGI and bullshit