Picture of The Accidental Cannon
On and off, I've been working on an all-metal (and hence non-shattering) version of the Jam Jar Jet. My latest version was supposed to be adjustable, but it turned out to be ballistic.
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Step 1: Do it outdoors!

When I first made this, I made it inside my shed, expecting a vertical jet of flame at most.

Instead, I had a can of burning meths ricocheting around my ears.


(Note to self - buy fire extinguisher!)

Step 2: Materials and tools.

Picture of Materials and tools.
I used five things:
  • An empty tin of tomatoes (ring-pull kind).
  • An empty can of coke. I only ever drink the full-sugar caffein-riddled version, but I don't think it's vital to the efficiency of the projectile...
  • My Instructables Leatherman. It's a well-used tool already. I even use it to open the shed since the door handle disintegrated (I really must get round to fixing that).
  • Matches. Long ones. You'll see why.

Step 3: Make it.

Picture of Make it.
C:\Documents and Settings\Teacher\My Documents\My Pictures\Instructables\PICT6911.JPG
Use one of the pointy bits to poke a hole in the bottom of the coke can, then enlarge it to around a quarter of an inch across.

Use the pliers to rip the top out of the can. No need to be pretty, but try and avoid too many sharp ragged edges, and don't bend the can, otherwise it won't fit smoothly into the tin.

Step 4: Fuelling and Firing

Picture of Fuelling and Firing
C:\Documents and Settings\Teacher\My Documents\My Pictures\Instructables\PICT6915.JPG
Put a splash of meths in the bottom of the tin. Just a splash, it's the fumes we're after.

Drop the can into the tin - if the fit is right, the can should take a moment to slide down as air forces its way around the sides and through the small hole.

Put a finger over the hole and give it a shake to generate plenty of vapour. Watch for spills from between can and tin.

Stand the can somewhere clear and firm.

Touch a flame to the hole.


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Richard Horse7 months ago
instead of tearing the top off, use a can opener no jagged edges at all!
Kiteman (author)  Richard Horse7 months ago

True, but, since I was hacking in my shed, I didn't have any kitchen equipment handy...

Is there any alternative fuels to use other than the meths
Kiteman (author)  Kason_McDougald11 months ago

Any highly-flammable fuel will do it.

Try an aerosol deodorant, or lighter fuel.

Nightkilla2 years ago
Try ethanol alcohol or a bit of propane.
boom man562 years ago
how do you put a hole in the coke can?
Kiteman (author)  boom man562 years ago
See step three.
how do you put a holes in the coke can?
Aron3133 years ago
Put a firecracker in the hole and replace the can with 5 gallon bucket and fill bucket 1 or 2 inches with water place can in light cracker and run!!!!!!! It shoots very high you should try it.
Mortar or Cannon?

As a Pyrotechnician with some Medieval reenactment experience, my answer is that it's a mortar.

A Cannon is actually only one of a variety of types of gun (see also Culverin, and Bombard), and they all fire predominantly horizontally to attack walls, gates or vertical structures. It generally has a longer barrel, we call it a barrel because the very earliest ones were made in a similar way to the wooden casks that were used to transport all kinds of loose goods, including Gun powder.

A mortar fires mainly Vertically and is used to attack Horizontal area targets, like smashing through the roofs of buildings. Named after the "bowl" part of an early form of food processor called a Mortar and Pestle, a mortar usually has a very short barrel for it's bore.

As a Pyrotechnician I use mortar tubes (sometimes called Guns, in the US) regularly and you definitely wouldn't want one of THOSE to auto ignite.
Kiteman (author)  Dream Dragon3 years ago
Thanks for that - I never knew the difference before.

I'll leave the title as "cannon", though, as I think that is a more popular search-term... ;-)
No argument from me on that, it's all cool.
Schober3 years ago
I'm assuming the reason it launches is that the thrust of the first ignition is too much for the can to hold back. Why couldn't you JB weld the can and the tin together? Would it explode? Or are you worried about excess alcohols burning in places where they shouldn't be? I've read some of the other comments below and it seems like you could just make the hole a little bigger and avert explosion.
Kiteman (author)  Schober3 years ago
I was experimenting.

The pressure inside a normal jam jar jet is very low, and the most I expected the soda can to do was jiggle about a bit. I was going to try a variety of lengths of jam jar jet by wedging the soda can at various heights, but the first go caught me out.
Schober Kiteman3 years ago
Sorry, I didn't realize how frenetic that sounded until you made that comment.
Kiteman, you rock! I can't wait to give this a try!
Matt214975 years ago
What if you hot glued the can in the can?
ilpug Matt214974 years ago
That would make a bomb, which, if detonated with the proper safety measures, would be cool, but in this application, DONT DO IT.
Cool idea man some of the best inventions were discovered by accident. One observation though, it's more of a mortar than a cannon really.
Kiteman (author)  backyardmunitionist5 years ago
Mortars have the propellant contained within the shell, and it is ignited by impact with the bottom of the barrel. Cannons have to be ignited.
Correct, that is how modern mortar shells work. However the manner of firing prior to self igniting shells was different. The difference I was referring to was that a cannon generally has a longer barrel for longer range and flatter trajectory as opposed to a mortar using a short barrel for high angle short range and more of a lob type trajectory. Either way keep up the good work man.
Kiteman does know everything. You know why? Because he's Mike Rowe!
do u know everthing?
Yes.  He's a teacher.
do his students know hes kiteman or is it like a secret alter ego??
At least one of his students is also an I'bles member.
what their user name?
Kiteman (author)  kelseymh5 years ago
Dumchicken4 years ago
why did your door handle desintigrate?
Kiteman (author)  Dumchicken4 years ago
Thirty year old bakelite tends to do that.

It's fixed now, BTW.
To take the top off the coke can a can opener works great. ive taken the top of coke cans with can openers before and it works quite well.
Kiteman (author)  whoelsebutaelx4 years ago
Oh, he tells me now...

tfrost19804 years ago
My Uncle taught me to make this same cannon except we used multiple cans and lighter fluid, not a new design its been made since at least the 60's.
Rokko86524 years ago
Would denatured Alcohol work? Don't want to have another container of stuff for homemade... Artillery... lying around incase friends don't brush up on local laws and call the police.
Kiteman (author)  Rokko86524 years ago
"Methylated spirits" is exactly the same thing. Yes, it will work very well.
can i use other stuff besides meth spirits: alcohol, laquer thinner, turpentine (etc) ?
Kiteman (author)  stefannasehi6 years ago
Any highly flammable liquid should work.
so charcoal starter?
That stuff is barely flammable!

just get it burning :o

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