This is awesome: A butane powered mini-gun with interchangable barrels capable of firing a wide range of ammo.

I started playing with this several months ago. I had seen the film canister cannon and wondered about the possibilities. Initially I saw this: Pirate Cubicle Cannon. I then saw several other implementations all using a sprayed fuel, typically Binaca.

I thought that "autoloading" would be better than having to spray fuel into the canister and attach it. I thought that the fuel-air ratio was probably too rich, not too light in the Pirate Cannon but I planned on making a small hole in the film canister to relieve the pressure and allow fuel to flow in if it were indeed too light.

I built a prototype using butane as the fuel, piped in. There was no problem, just a _very_ rewarding *loud* report + fireball followed by insane laughter. Finally I calmed down and began thinking (ir)rationally.

As I thought about making a hole, my thoughts morphed from a small one to a larger one to a barrel: a-la the "ultimate spit-wad shooter".

I tried it and the performance was beyond anything I expected. I used a Bic Round-stik pen as the intitial barrel...hunting for ammo... would you know that Tic-Tacs fit really well in a Bic pen? Yeah and when the tic tac hurtled across the room, bounced of an angled door, down the hallway and ricocheted arround in the bathroom for a while I knew I had something.

I scoured the web looking for anything similar, I found one thing at the BleachSoft website. At instructables, I filtered through all the KNEX guns, marshmallow guns, airsoft guns, etc and turned up nothing. I have however recently seen several similar projects appearing here on instructables:
Q-Tip Gun
Small Dart Gun
Axe Rocket Launcher/ Mini Spud Gun
Mini Spud Gun, Classroom Nemesis
Mini Spud Gun
Now that my fear of being the sole corruptor of the DIY builders of the world has abated, and I will not share sole responsibility for the fallout, I present my work so far.

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ilpug2 years ago
I have been working on a project that involves an Airsoft gun powered by this system but using shells, really just individual chambers, to fire. I just witnessed the raw power of butane, by having a PVC cap shot into my wall. please, don't be dumb like me.
Quw103 years ago
Wanna make this more interesting you should make a crude blow back loading system so it atleast reloads by gravity, you know like opening a trap door or something but probably will be tricky
Kiteman7 years ago
I would like some muzzle velocity measurements. I am exploring high-speed photography for this and other interesting image capture.

Try a ballistic pendulum instead:
bench.worker (author)  Kiteman7 years ago
This is an interesting idea that I also had in the back of my mind. It may acutally be simpler than I imagined it. Thanks, I'll check it out.
Another way to find speed is to make and cast some ballistics gel (i think there is an Instructable for this), and fore into it at point blank range. Then, i think, by using some fancy math that im sure you can find somewhere, you should be able to find out how fast its going.
how bout a defined shutter time and a scale in the background like 100/S shutter and a metre rule as close to projectile... take start of the blur to the end of the blur on the ruler to find out the distance travelled in 100/S x 100 gives you cm/s and leaving it undivided gives you M/s
Or video at a known frame-rate (say 30fps) and compare adjacent frames?
bench.worker (author)  Kiteman6 years ago
Alright, I have been experimenting with an ~30 fps video camera. I have collected quite a bit of data but have not completed the analysis. What I have found so far using a marshmallow as the projectile: 1. It is difficult to see in flight against a well lit dark background 2. It can travel 2m in a single frame 3. Frame rate is constant but exposure or "on" time varies with ambient light 4. This means "off" time varies as well 5. one must determine the "on" to "off" ratio for accurate calculations 6. it would be nice to have a "slow" constant velocity object to calibrate this Roughly, I can estimate that we're seeing 91 m/s or ~300 f/s. Stay tuned, detailed analysis to follow along with better performance
1, 2. Try a banded background - black and white stripes of known width (1cm?) to allow accurate measurement of distances, plus increasing the chance of spotting the 'mallow.

At 30fps, 2m in a frame = 60m/s, not 91m/s.

60m/s = 134mph = nearly 200f/s (not 300, but still impressive).

3, 4, 5, 6:

Make or buy a clock with a smoothly-moving sweep-hand (as used by crash-test centres) or a simple "bob" pendulum of known length (and hence calculable period).
bench.worker (author)  Kiteman6 years ago
The banded background sounds interesting I'll have to try that. As it is, I've included a measuring tape in the video which I then use to calibrate the image processing software. As for velocity calculations: At 30fps you would be correct if each frame was exposed for that entire time. I was interested to discover that this is not usually the case. Time is necessary to record each frame. Beyond that ambient light can change dramatically--this is dealt with by varying the exposure time of each collected frame. The maximum exposure time would be 1/30th of a second, but under bright lighting conditions this could be significantly less. The meaning of all this is that the data collection rate is 30fps but the actual exposure time of each frame will be somewhat less than that. I'm estimating that this could 50-60% with the setup I'm using. Hence the time scale of the recorded distance per frame is less than 1/30th of a seocnd. I do like the pendulum idea. The need for a known velocity is not so great as the need for a fixed velocity. This will allow easy calculation of the exposure time of each frame as a ratio of the collection rate of 30fps.
yeah I used the 100/S as a way of getting a direct measurement, timing would be everything and prefocusing is a must but the video idea might provide more reliable figures say: (travel over 10 frames)/30 = velocity in M/s also using ten frames cuts down on error by a huge amount.
bench.worker (author)  killerjackalope6 years ago
These are good ideas. Thanks for your patience with this. I have been spending time elsewhere of late, but I am interested in collecting this data. I will try out these suggestions - there are a lot of potential pitfalls, but planning to avoid them will take time. I may get lucky just by trying.
yeah a decent camera with a reliable framerate or shutter timing is the main thing to get over then timing the firing and capture so video is a better bet
youy know airsoft bbs fit perfectly in bic pens... just an idea
bench.worker (author)  shadowgravity6 years ago
Just a GREAT idea.... Haven't tried it myself yet, but i've been eyeing them for a while...
An Airsoft bb does not actually fit very tightly in a bic pen tube. Not a big deal, but annoying, as it may roll out.
Raycing6 years ago
Some FYI for the high speed photography,you can buy glow it the dark airsoft BB's which might make tracking the projectile a little easier.
bench.worker (author)  Raycing6 years ago
Good to know....thanks!
those things are almost useless. When fired, they cant be seen even in a totally dark room.
try shooting cotten balls soked in alcahal or other flamable liquids
Oooooh flaming projectiles i like o__0
ilpug manmelvin3 years ago
that is a really good idea. dangerous, but good.
Fireballs! Hehe. Ha ha ha. MWAHAHAHAHAHAHA! AHAHAHAHAHA! MAHAHAHAHA! Sorry you had to see the evil genius in me...
Matt D6556 years ago
Not half bad an idea try putting kerosene in a super soaker thats real fun.
that is astoundingly dumb. normally i wouldn't be that out-and-out rude, but that is REALLY DUMB.
Colonel885 years ago
Mine doesnt work... My dad says that if i use something flammable it will go up in flames. i tried using the easy way by putting the barrel assembly on a unmodified lighter and there IS a lot of fire, but i think it would burn up the ammo. I'm going to do this project another way. Cheers.
ilpug Colonel883 years ago
Just follow the directions in this instructable and it will work fine, without the huge conflagrations your dad fears.
does it have to be a ronson lighter? or can i use a bic lighter?
Just brad names, no difference.
well, $10 bbq lighter is too expensive for me. is there something that can replace the piezo? will it work if with a flint lighter?
Topunisher4 years ago
here's mine
I kinda cross between ethago and chaslak invention its the same principle...I think. (' '_,)
jupeter54 years ago
Wow this is really cool i must build one, keep up the good work
the cake is very delicious.
Butane Madness?
I'm making one charged with HHO----In the syringue?!
Push the Embol? to charge.
mine uses a mini can of axe spray for fuel and i use a piezo thingamabob to ignite it. it works really good and flames go out after the projectile
matroska4 years ago
I just built mine today from a broken butane torch gun. Only the flame part was broken, the valve and butane tank were all OK. So I built my combustion chamber with a Steadler sharpener and hot-glued a hollow pen as the barrel. I used the igniter from the butane gun (trigger like, very nice) to light the thing. However, butane NEVER worked. For whatsoever reason which escapes me. I could only get it to fire when spraying Axe. I assumed this was because the axe is sprayed like a small mist and thus my spark hits it. Any hint on why butane would never work? Thanks! PS: my design worked super well also just with axe!
krugerm4 years ago
I have a quick question do you have to open the chamber every time you reload because of lack of oxygen, or have you found a way around it? I ask because i have some mini spud guns and they can have enough fuel, but i run out of oxygen to do multiple shots without reopening the chamber.
for your future design, use a refillable flint lighter for gas flow then a shocker for your ignition system but make a hole in the side of the film canister and stick it in thereand a nother hole on the other side of the canister,also by useing a refillable flint ligher u won't acidentally set off tthe gas
i made one and modeled it to look like an ak-47.
toogers toogers4 years ago
what the heck? i clicked "add comment" and it appeared as a reply to your comment. sorry for the mistake.
u can delete ur own comments u kno?...
essentially use a bic lighter for your fuel control, then attach an electrical shocking butane lighter or something of the sort into a foregrip below the film canister to ignite the gas.
this looks alot like a lego gun
smeata6 years ago
(removed by author or community request)
bench.worker (author)  smeata6 years ago
That sounds pretty cool. I'd be interested in pics / explanation of the computer control, valving mechanisms, and purge mechanisms..... Cheers.
(removed by author or community request)
NIJU! smeata5 years ago
you should go to a aldie store and buy a $90 6MP underwater cam/vid recorder. i did (:
could you send me the schematics in Quite Universal Circuit Simulator (qucs) format?
(you could send it in any other format if you wish)
this sounds very worth while, would you be able to send me the schematics for this and software that is loaded on the PICAXE 18x, muchly appreciated.
bench.worker (author)  smeata6 years ago
Very nice! Thanks for sharing. A couple of questions: What amount of butane have you found to be ideal in your setup? Are you using a standard film canister for the chamber?
pfft hahaha does that 212 IQ include common sense? not to call you out or anything but i doubt it.
If you don't mean to call someone out, then don't.
pfft hahaha
Effective and they look great!
!revenge!5 years ago
it would be so friggin awesome if someone made a desert eagle out of this thing :P
forte19945 years ago
if the valve to the butane tank failles you will blow up your hand . right?
aflacgoose5 years ago
Great idea for a spud gun. Looks very cool.
s = v sin a t - 1/2g t 2

v = (s + (1/2g t2))/ sin a t

g = gravity (9.81)
s = distance
t = time, meaning you could use the time code of a video etc
a = angle of launch

make sure you launch from ground level though, or the equation doesnt work
btw how do u calculate/measure the fps of any gun?
corpse where is this for exactely (im just curious), could u explain this to me? pls? (im such kind of person who likes fysics and stuff but who not always understands)
finnster5 years ago
This is pretty sweet, but I haven't managed to shoot a potato out of it, it just makes a fireball, which is cool.
Jupitane5 years ago
By any chance do you know the FPS on this nice cannon?
jeoncs5 years ago
This is great I am going to scrounge for a lighter when I get home!
venom525 years ago
Finally finished mine made of steel welded together
PKM5 years ago
Very nice! I have considered making a lighter-fueled gun like this before but was always slightly nervous about having the butane delivery tube inside the combustion chamber for some reason. Perhaps from blowing up enough lighters deliberately to know that I don't want it happening in my hand :)

Fortunately I still have the butane tank from making my latest version so I might try giving that an incorporated fuel supply. Not sure how long the thing would last with a one litre combustion chamber, but it's worth a try. Now I just need a refillable lighter...
Kaiven5 years ago
This 'ible is great! The only thing I was not sure on was how and what the syringe does... Maybe add info in about it?
The syringe is to purge the chamber. When the butane ignites, it leaves behind a non flammable gas, and butane needs oxygen to combust. By the looks of things the syringe draws out the old air, and then you can pump in clean air. Are/have you making/made one of these? Me and my good friend are currently, we've made the barrel, the combustion chamber, and just last night I started on the electronics, I couldn't find a barbeque lighter so I just soldered some wire onto the lead coming from the piezo, then covered it with trusty heat shrink. Hope that helps! -Kryptonite
Thanks! I might make one. The one I have now looks pretty real, just needs new paint. The chamber is too small though.
Can you post a picture? I'd like to see other peoples work. It's a shame that this instructable is disregarded almost, it's a great gun, and it's not even featured.
If I ever remember too lol.
Yeah, I'm pretty busy to remember to do anything on 'ables these days, it's sort of sad because I love instructables!
I just bought 3 electirc lighters from a dollar store today :D I might wanna try this now. Do you know if I will lose gas when I take apart the lighter?
If you crack the section that the gas is kept, then you would lose the gas. And if you did do that, then do it outside. I'm not sure how poisonous butane is, but it's dangerously combustable.

What type of lighter have you got? Like a candle/barbecue lighter or a cigarette lighter?

I've found it's sort of hard to work out what to do with the lighter but I worked it out. Any questions please ask. =D
I used a small lighter with the electric sparker in it. I found that my sparker was shorting out in the lighter and in the chamber, so that is why it didn't work. Remind me, and I will post a pic :P
Sounds good, I ended up using a cigarette lighter identical in the "internals" to the one on this instructable. But instead of using a different piezo, I just soldered another wire onto it, then covered it in heat shrink tubing. Perfecto! I might post a pic one of these days...
wat does the butane gun do? flame thrower? sprayer? what does it do?
This gun shoots a range of small thngs, the butane part is just for the combustion, which makes rapidly expanding gasses to push the bullet out the end of the barrel at high velocity.
is it like real fast or is it just like a strong nerf gun?
REAL FAST. I think that would be your answer. =D
Kryptonite5 years ago
For every one out there, you can use the small wired piezo, just solder some more wire on, then heat shrink it.
fd935 years ago
for the pressure problem try drilling a small hole in the chamber and plug it with some hot melt glue them if it fails to fire punch the glue in and the pressure will release through the hole rather than turning the canister into a pressure vessel
mag4006 years ago
where do you get wood and film canisters?
the film canisters r easy to get, go to your closest camera store, ask if they keep their film canisters, then when they say yes, ask them if u can have some. And the wood? Hard ware stores.
venom525 years ago
Cool design bro.I just made mine but with a few tweaks.I took another canister,fit 5 mini tubes inside,Ok well to make a long story short its a revolver.(but you have to turn it manually)For you crazy James Bond types,check out Pneu-Darts.They're tranquilizer darts and pretty cheap(couple bucks apeice).They are empty so you can fill them with whatever you want and anyone can buy them.I haven't done it but think about the possibilties.I think the site is just,but if not just Google.One more thingMini nerf darts fit over a pen plus you can add all kinds of neat gadgets like a syringe or capacitor.Use your imagination.Have fun:-)
can u send me a pic of what yours looks like? If u can't its no big deal. just wondering. :)
Lazyazz4305 years ago
What if u could make the film canisters like bullet rounds. Then make a revolving pistol type gun. thats what im working on.
ps3king15 years ago
HEY i love this i might try it actually i just posted an instructable on how to make one of these things but using a water pistol you should check it out
olirulesok6 years ago
good instructable
jeff-o6 years ago
Okay, followed every step till now. The butane fills the chamber, the spark arcs across the wires, but no bang! Any idea why I can't get the gas to ignite? Too rich/too lean/not enough oxygen?
jeff-o jeff-o6 years ago
Nevermind, it was a bad air/fuel mixture. Anyone who is building one of these must really pay attention to that, otherwise the butane won't ignite. It's also important to have some sort of air purge system in place, be it a syringe or breach-load chamber, that allows you to fill in fresh air for each shot.
Blow off the smoke like they do in the movies...
bench.worker (author)  jeff-o6 years ago
Yep. Happy shooting.
What about heat shrink tubing? It only gets but so small, come in large packs and would fasten to the fitting.
GZNG6 years ago
rather than just pop the film canister in, why not hot melt glue it there, make a hole in the top and cover with duct tape and when the pressure builds up, pull off the tape or maybe the tape will fly off by itself
Ur cool man Oo Gotta try that out!
skrubol6 years ago
A couple check valves could possibly make for an auto-purge. Have a check valve to only let air go out of the barrel (it'd have to be placed behind the barrel,) and to let air in to some other part of the chamber. When the butane ignites, it expands, expelling the projectile out the barrel. Momentarily later, what's left in the chamber cools down and contracts, drawing fresh air into the chamber. Biggest problems I see with that are that the barrel check valve will probably be too constrictive and slow the projectile down, and also the valve will probably get torn up quickly (assuming simple home made valves.)
dude you are frikin awsome i tried it and i shot a tictac at a can it dented it and the tic tac exploded
Kweltan6 years ago
Would you be able to post a video of you firing the spud gun???? great instructable though!!!
theosullis6 years ago
there is a way yo make this so much simpler but its too hard to explain.
it looks good but is there a chance it could blow your hand off.
Mattrox6 years ago
awesome job cant wait to try it out
venom526 years ago
Awesome! I have to build one :)
I've just completed mine! But I did a few things differently, mainly because I didn't have the parts you descried in the materials needed.

Here's an image of what mine looks like:

I used a wooden stake for the wood, a medicine bottle (though not very interchangeable), and a 6mm airsoft barrel with bbs.

One minor, but less complicating change I made to your design was the connection to the piezo element. I left the pen spring out and used solid core wire, which is easy to wrap around and won't come off. It also made the bridge for the spark easier to do.

I am more than impressed and pleased with this nifty little device.

Though it is fun, it's not exactly consistent in both firing first try and fps, thought it was made for under 10 bucks, so there's not much consistency to expect!

Do you have any techniques for firing and FPS consistency?

Thank you for the instructable!
bench.worker (author)  cliche_cliche6 years ago
You ask a great question...and thanks for the pic! I've found that the following points are key: 1. reliable spark - sometimes these piezos fail, or there is arcing between the wires in places not intended... 2. reliable fuel-air mixture. This is important for both consistent power and consistent triggering. I'm working the second problem. I have a nice prototype and am working on a field-deployable design that is a bit simpler to construct. Stay tuned.
Yellow846 years ago
I just finished mine today, but it doesn't fire each time i click the piezo lighter. It is sparking and there is fuel in the chamber but I can only fire it sometimes. Do you have the same problem? Is it just the fuel to air ratio? Or is there something I would be able to do about this?
bench.worker (author)  Yellow846 years ago
It is hard to say.... See other comments here, we discuss some of these issues. Most likely culprit is unreliable fuel-air ratios. Check to make sure the piezo is always firing right.
mkamchin6 years ago
how much did this cost you?
bench.worker (author)  mkamchin6 years ago
Very little in materials, quite a bit in time. Lighter: $1 Scrap wood: $2 Washer: $0.15 ...
im_an_alien6 years ago
How many shots can you get out of a lighter? The only electric ones I could find at publix were non-refillable, and I don't have many options for where else to get them (might try kroger though, there's one just across the street from publix).
bench.worker (author)  im_an_alien6 years ago
Lots and lots! I've never counted, but you need about 1 to 1.5 cc of butane gas under normal operating conditions... given butane is 58.12 g/mol, 0.601 g/ml (liq), and 0.0025 g/ml (g) and using various methods of calculation one arrives at somewhere between 160 and 360 shots per mL of liquid butane...assuming you aren't wasting any. How many mL's are in a standard lighter? I'd guess approximately 3.5 - 4.0 Is that enough?
eeeXsmart6 years ago
sweet!!!!;) a bit complicated, but great!
whiskey76 years ago
Great work! made a simple version and found that using a med. bottle the blow back pop is eliminated.
Kayjay6 years ago
lol "This is LOUD = ouch my ears, especially indoors" i find that funny (agree with you thought) just imagine lol i have been shooting like a 5 foot spud gun in my house, when it goes off my walls are still rattling afterwards lol

p.s. good instructable lol
bench.worker (author)  Kayjay6 years ago
Hope you've got good ear protection...and tolerant neighbors! Cheers.
Luxordo56 years ago
can you tell me what exactly what the syringe does? I have one and I would like to make use of it.
bench.worker (author)  Luxordo56 years ago
The syringe was modified to become a pump. I used it to pump air into the chamber after firing to purge the products of combustion and prepare for the next shot. This was supposed to be an alternative to opening the chamber to vent it. You need to create some valves so you are moving air only 1 way. With just a syringe you will be pulling air out of the chamber, then putting the same air back in. I made my valves with some latex membrane and glue...they worked great. Good luck!
bolabola6 years ago
the gun is really cool. I made 1 myself but i used a kitchen stove lighter(da 1 with the long barrel).i separated the chamber from the lighter.1 disadvantage of this 'gun' is that you must get fresh air into it for the next shot,I am thinking of connecting a syringe to it so i can pump air into the chamber for faster shooting :p
bench.worker (author)  bolabola6 years ago
Yep you're right. The fresh air is necessary with this design. I tried the syringe pump idea, but found my syringe too small for the task. I'd try a 30cc or larger if I were to try this again.
is there anyway to fix a broken piezo? i don't want to salvage a whole lighter just for it
bench.worker (author)  thepianomistro6 years ago
Sorry, I've had no success with this....but lighters are cheap. I've only had a few failures out of many.
sprtwin16 years ago
For speed measurement, there is a much easier way. Take two extremely thin sheets of paper and suspend them a known distance apart. Shoot the projectile through the two sheets while using a microphone to record the sound. Analyze the wav file on the computer, and use a simple rate * time = distance formula.
this kicks mean f*** ass man good work :)
Spedy6 years ago
Wow! This is great. I HAVE to make one of these some time. I think I'll have to go w/o the fancy wood handle for the first try though, maybe when I upgrade mine I'll add in the nice handle assembly. 10/10
ilikebombs6 years ago
hey everybody? I am still kinda unfamiliar with some stuff and was wondering what the collaberations videos are and for?
mag4006 years ago
could you PLZ. tell me what the drill bit is called and where you bought it. thanx.
pure genius
T3hpw9ag3 6 years ago
Awesome- definitely one of the best home made weapons. When I mean home made I mean literally as in everything you need is at home. Not to mention very clear instructions.
skaterat136 years ago
sweet itll take me a while to read the directions tho!
Sweeeeeeeeeeeeeeeeeeet :-)
hunter cd6 years ago
Ducky Boy6 years ago
Oooh, the lighter idea is wonderful! I am most definitely making one myself. Also, an idea, I saw this in another instructable... You could cut a hole in the bottom of the film canister, heat the bottom, and then slide the barrel in. It's supposed to make an airtight seal, no hotglue needed :) Although it couldn't hurt just to add a bit.
bench.worker (author)  Ducky Boy6 years ago
This sounds neat. I'm interested in airtight and strong..mostly strong. I'll give it a try. Thanks!
pmac936 years ago
on the double handle style gun what did you use as the barrel and how did you reinforce it?
bench.worker (author)  pmac936 years ago
The barrel is a random smooth wall tube I had lying around. It is not plumbing pipe unfortunately. I like its dimentions very much and would like to find some reliable source of something similar...i'll let you know what I find. By reinforcement I assume you mean at the barrel-lid junction. The barrel penetrates ~5mm beyond the lid, glued around the outside. There is a thin piece of wood supporting the barrel--this piece is glued both to the barrel and firmly to the lid. This adequately strengthens the junction.
Muzzle velocity figures are very easy to calculate with simple projectile motion formulas based on the principles of Newtonian physics. If you can measure:

Angle of inclination at launch
Flight time
Distance of Flight
Vertical Acceleration (roughly 9.8m/s2 most places on Earth)

You can solve for the velocity at the time of launch. Simple and accurate. Can't remember the formulas right now, let me look it up and get back to you.
one problem, wind resistance will through off your calculations.
bench.worker (author)  hamishofangus7 years ago
This is assuming of course no friction. In this case we have relatively light projectiles of low density traveling through air. Marshmallow is larger than a cubic centimeter and weighs what, a gram? Volume-wise I think it is mostly air. I believe the error induced by assuming no friction would be substantial. It would underestimate the real velocity--this may in fact be useful, defining a lower limit on performance. There are other more suitable projectiles--still there is another issue. The data necessary to do this calculation do look simple on paper but to actually collect these in with any accuracy is challenging. These are the two main sources of error i see in the calculations and are why I have not pursued this method.
The_Kangsta7 years ago
can you use a advil bottle instead of a film canister? It would be harder to fly off.
bench.worker (author)  The_Kangsta7 years ago
Yes....but then this could be called a bomb. The lid acts like a chamber over-pressure safety, preventing the chamber from fragmenting or cracking. I don't know how an advil bottle would hold up to the stress of overpressure--perhaps the lid would still fly off, but it would have damaged or ruined threads, possibly with fragmenting lid. Or it might work great and no one will lose any body parts. I'd think carefully before trying this.
Yeah I tried it with the advill bottle and it works great. When the barrel gets clogged theres just a hiss of steam. Just it takes a while screwing it on but its very rugged
yeah i would like a pic too
bench.worker (author)  The_Kangsta7 years ago
Mildly scary, but as always, "theory guides, experiment decides." Thanks for this info. Consider posting a pic...we love eye candy.
I used some metal slugs i found in the bottom of my tool box and they're incredibly lethal; i hit a tree on the other side of my street.
bench.worker (author)  The_Kangsta7 years ago
Sounds interesting. I surprisingly have not tried anything much heavier than a tic tac. Thought about AA batteries....just for a moment. The thing performs well, no?
Oh definitely. I put sights on my gun and hit stuff across the street. I guess you could try AA batteries but it might be too heavy.
no it is to hard to fire and then it will just flash and sit there...
manmelvin6 years ago
Wow i tried to make somthing like this but it doesnt have an kind of chamber so it didnt work.
ggr_man6 years ago
man ... i cant get the gas in the film canister to light up any one has suggestions? in my design the trigger is seperate from the gas flow , both the trigger and the gas flow work but when i close the lid the spark just wont light up the gas ...
C:\Documents and Settings\Owner\My Documents\My Pictures\2007-08-14\תמונה 001 copy.jpg
bench.worker (author)  ggr_man6 years ago
It is a bit hard to see from your pic exactly what is going on. I have a few suggestions though. 1. usually this is from too much gas, not enough air. 2. you may have a gas leak at the gas supply end. 3. your long gas tube may not be injecting enough gas 4. your spark gap may be too short - lengthen it. Use your nose, your ears, and perhaps your other senses to determine what is going on. Good luck.
listen i did another design exactly like yours but it still wont light up the gas... i have a good spark and the gas is flowing (see the pic) and it allways seem to fire after i get the canister out and back in... i think its something with the air to butane ratio but i dont know how to fix it... help plz
C:\Documents and Settings\Owner\My Documents\My Pictures\2007-08-17\sdf.jpg
bench.worker (author)  ggr_man6 years ago
There is of course no magic to the physical arrangement of the parts. I admire your persistance with this. I would like to see you succeed. Some additional thoughts to consider: 1. is the butane mixing well? - is the stream forceful? Perhaps too weak? - is the supply tube directed toward the upper wall? - are you waiting long enough for mixing? Too long? - is the butane flowing out your barrel rather than turbulantly mixing? 2. Too much vs too little butane? From the pictures the flame looks weak - I have not done this test, but judging on my flow rates I would expect a larger flame. I do not use the brass orifice you show--perhaps you did it only for the demonstration to preserve the tube. One picture shows what I believe is flow directed colinearly with the barrel--I think this is bad. Again most of these thoughts are not based on exhaustive testing, just expectations. When I am building these usually I play with the butane flow adjustment lever prior to gluing everything together finally. I find the optimum setting for ease of use / consistency. This typically is higher than the middle setting. Good luck! Persevere!
very nice gun, you should try to add power aswell as versatility, that'd be AWESOME
mag4006 years ago
WHAT DID YOU USE TO DRILL THE HOLES AND RIDGES IN THE WOOD??? ive been looking everywhere and i can't find one.
bench.worker (author)  mag4006 years ago
There are many options for this. Many rotary tools (dremel a popular brand) come with bits like this. I show a pic of the bit. But a router, a standard drill, wood-carving tools, fire, a hot soldering iron...all these would work. Good Luck!
im making a gun thats simular to that one though the combustion chamber is a big mini MM tube instead of a film canister
bench.worker (author)  the gizmoman7 years ago
I looked at one of these containers today. I liked it:
1. Hard rigid plastic including lid - no washer needed
2. Lid hinges - overpressure just pops it open, doesn't throw the lid/barrel
3. Barrel installed in lid would allow easy breechloading

1. Cannot interchange barrels
2. Will it hold the pressure / heat necessary? (probably)

The only other concern is that it is quite long for its diameter. This resembles the syringe from which I have never seen performance like the film canister. This may be due to my impatience, but is more likely related to chamber geometry and gas mixing / flame propogation. I suppose that an ideal chamber would be spherical--the film canister more closely approximates that than does the m&m container.

I am interested to know how this turns out, let us know what kind of perfomance you find.
if you think you can't change barrels just use duct tape
bench.worker (author)  bench.worker7 years ago
For Cons....that is cannot interchange barrels without cutting that nice hinge.
dont put to much fuel in it and put a fairly large tube on it cause i put too much fuel in it and it riped the hinge off (oops!!) (i have a pin casing for tube and it shoots ammo then the cumbustion chamber off!)
reeding6 years ago
DUDE!!! This would be awesome for my...uh...friends birthday party! yeah that's it! Could you use darts? Not at people or animals (im required to say that) but could it be done well enough to puncture...uh...stuff?
i have built a tater pistol (i built it to shoot peaces of potatoes ) thats simular to the future design picture and its breach loaded too! ( i dont just use potatoes)
bench.worker (author)  the gizmoman7 years ago
"Picture, Picture, we all want a picture!" And what besides potatoes have you found interesting...?
sorry abou picts I don't have film for my camera and i have created ammo for a new gun i've built (i have made a basic pistol and molded paper arounded it to make it more realistic ( i got the idea off this web sight )
dude this rocks I have made all kinds of these types of things but this one is by far the best
bench.worker (author)  supergluerules7 years ago
gameboy7oa7 years ago
dude where did u get the syringe?????
bench.worker (author)  gameboy7oa7 years ago
You can pick these up all over the place. Medical supply shops...craft outlets...electronics supply shops....
I am building one where the lighter is fully enclosed in the handle, and the sparker has been taken out and placed in a convenient spot for the trigger. this way the gas is separate (at the top where a cocking lever would be). The chamber is sunk into a big hole in the body, and the barrel(s) are attached to the cap. as a bonus, my lighter came with a bright blue signle - LED flashlight at the bottom. i flipped it around and am using it to light up the gas tank, so you can see when you need a refill. i am almost done building (only barrel left), and will post a pic when i'm done. hopefully it works good. my prototype worked great.
Here are some pics. More stuff at
bench.worker (author)  T3Hprogrammer7 years ago
Thanks for posting your work! I like what you have done here. Don't you just love the flame and the varying sound it makes with the various barrels? I see you are using the fuji style canisters here. Do you have much trouble with the lid/barrel assembly flying off?
So far I haven't but I foresaw that problem, and added a single layer of electrical tape around the inside of the can (where the cap pushes on to.) That is why the visible part of the can is black. It makes it slightly harder to change barrels, but hasn't failed yet.
try shooting just the film canister bottom it creates a really LOUD bang & shoots the bottom at least 20ft!!!!
bench.worker (author)  the gizmoman7 years ago
This simply mirrors the film canister cannon. It is a fun operational mode to be sure and a great noisemaker.
my favorite thing to do is sneak up on someone and shoot it at them or up in the air it scares the death out of them and it hurts like crap too!
What is the washer for now?
bench.worker (author)  Wingmaster7007 years ago
The washer is a support. The canister lid is flexible, soft. If it were glued directly to the wooden body I believe it would not be durable at all. The washer keeps the lid flat, gives something solid to glue the body to, and provides a platform from which to wrench off the barrel assembly for chamber purges or barrel changes. I have substituted a rigid plastic piece for this -- it may in fact work better, bonding stronger with the hotmelt glue.
i didn't have a washer, so i just hot-glued the cap right onto a small piece of wood. no support problems, but it's a little harder to pull the barrel off (the cap wants to bend, like you said) it's not really necessary but it helps.
I used a ply wood disk instead of a washer
some one said that they got some gotchas from gluing the clear tube to the gas cartrage. i found a way around that.1st get a twist tie and burn off the paper on it.then cool it under some cold water. after that take off the black nozzle atach the clear tube and tie on the twist tie to it.[ps leave enogh romm to pull the twist tie forord]
Where do you get the butane refills, without ordering online?
yea, i found some at cvs. you just have to ask for it over the counter.
A lot places. They even sell them in Bed Bath and beyond. I guess butane goes into the "beyond" category.
maxpower497 years ago
this gun rulz
Cam F7 years ago
i saw a video of a police instructer shooting himself with a gun that "wasn't loaded"
bench.worker (author)  Cam F7 years ago

Every gun is *always* loaded.
gyromild7 years ago
Which one is the final build? It seems like there are several designs in here.. I've built, several guns along the same idea a couple of months back, and the goal was to get it to fire everytime with just one pull of the trigger...encountered a few problems.. I'm interested to know how you solved them.. 1) I used syringe as well, to get a nice mixture of air+butane, just does seems to get the ratio right, it doesnt fire everytime.. 2) How to flush the fumes accumulated in the cannister after firing. Thought of a valve mechanism, but perhaps you have a simpler approach.. 3) Piezo igniter doesn't seems to do the job well for me, i opt for battery powered continuous sparker.. even then, i have to hold the trigger for a second or so before it pops (butane+air ratio issues) Thanks in advance..
bench.worker (author)  gyromild7 years ago
The initial picture: white lighter, black barrel is the final build. The others I have also made with the exception of the last picture illustrated. This is a future design I have laid out but not yet built. I need to edit a bit to explain this a bit more clearly. I was rushing to post and was having problems with creating "notes" on the pictures. The basic design should get the specifics pinned down, from there it is easy to concieve the other designs and branch out to others. Thoughts on problems: General: I also tried to hold half-trigger for x seconds and then full trigger to spark. This did not work reliably for me. I don't believe the gasflow rate is constant throughout activation of the valve. The best method I found was three medium quick half-pulls to charge the chamber with gas. You could then wait for quite some time before pulling fully and delivering the spark ( of course with another puff of accompanying butane ). This simulates the effect of 1 pull for 1 fire each time. Once you get the feel of how much butane is needed, this works maybe 90-100% of the time--there is a slight learning curve. Aside from amount of gas I think that mixing is key. The time necessary will vary depending on design: -How forcefully is the gas injected into the chamber? -What is the flow path? -How much time is allowed for mixing? I think the idea is to create as much turbulence as possible. The more turbulence, the better the mixing, and the less time necessary for mixing. I would think that there should be an optimal tube diameter for this. As for path, I positioned the tube so that it was directed at the upper chamber wall. Butane is heavier than air, it will fall with gravity. I wanted a forceful stream to hit the upper wall, divide and flow around both walls downward to collide in the middle at the chamber bottom wall. This would create turbulent mixing. 1. Syringe. I was also disappointed with this. I expected it to work out better and allow data collection while changing a number of variables fairly precisely and accurately. I attribute this to my spark being at the barrel-chamber junction, the chamber diameter being smaller than the film canister, poor gas mixing, ? I did learn a few important things from the syringe, but it in general fell below my expectations as an experimental tool. 2. Chamber flush. I'm still working on this. In the sixth picture on the intro page you will see a model with a syringe mounted on top. I designed a simple valve mechanism for this syringe to pump air into the chamber. My target was 1-3 pumps, it actually required 6-8. This was laborious. A larger syringe would no doubt be better. I have found it much easier simply to seperate the chamber-barrel from the breech-lid. I shake the chamber a few times and snap it back together. This becomes a rather quick practised motion. I have thought of hinging the pieces to make this more like a break breechloading shotgun. The third pictured design started out with that in mind. It is breechloading, it was so simple to seperate and rejoin without the hinge that I have not yet build it. 3. Piezo. I have thought of electronic spark also. I have avoided implementing it as yet simply because I don't like the bulk I imagine the circuit and battery will cause. I do like the concept and would like to see your design. Your mileage will vary on the piezos. I have had some bad ones, but the pictured "brand" have always worked well for me. There are however sometimes problems with the spark jumping at an unintended spot and not in the chamber. This can vary seemingly randomly from shot to shot and needs to be addressed if present. Hope that helps some. Consider posting your project, I would certainly be interested in seeing what you've done.
Thanks for pointing out things that i have overlooked..certainly helps

By the way..I don't like the bulk I imagine the circuit and battery will cause

You got it right there, the setup is bulky..
I extend the wiring and place the sparker's switch next to the lighter's lever. So i actually need two fingers to pull the trigger(s)..

Well, the idea was to have continuous live sparks in the cannister, then let the butane flows in. It'll pop as soon as the mixture is right...
The downside, sometimes it takes 1 second, sometimes up to 8, sometimes it never pops at all..

Now that you mentioned terbulence mixing, wonders if Bernoulli Principle would work..
Add an air inlet on the clear tube, reduce the size of the tube's outlet to create a jet stream of butane. That will spray a misty mixture of butane+air into the cannister..
Similar to perfume sprayer idea..

I'll give this a shot, and i'll get back with the outcome..
Another thing you could try is sealing the end of the gas tube with something, and poking many pinholes in the tube along the length of the chamber. Also, is there any specific reason why the whole chamber is connected to the barrel instead of just the cap? I think it would protect the wires and gas tube better if you reversed the chamber.
bench.worker (author)  T3Hprogrammer7 years ago
This multiple hole idea might just work. You would run the risk of creating too large of a collective cross-sectional area and having the gas exit with minimal velocity. It would be distributed linearly in the chamber but would still not mix well. As for the chamber + cap question. I think you are suggesting attaching the barrel to the lid and having the wires and gastube enter the bottom of the film canister essentially "reversing" the chamber. Photograph number 3 on the intro page shows this arrangement. You are correct, the wires and tube are protected from being bumped / misaligned during chamber purges and barrel changes. Advantages: wires protected, easy breech loading (very nice) Disadvantages: easy to damage barrel-lid joint when seperating device, difficult to adjust spark gap wires and gastube. Thanks for your thoughts!
you could just spray a hint of axein the barrel :)
cool, so basicly a canister fills up with butane then you light it with the ignitor to make the rounds pop out!?
bench.worker (author)  !Andrew_Modder!7 years ago
Basically yes. However, saying the canister "fills up with butane" isn't exactly correct. The canister will have somewhere between 10% and 50% butane, the rest being air. It is much easier to get the mixture too butane-rich in which case it will perform very poorly.
lemonie7 years ago
Quality. L
A_squared7 years ago
This is much better than my idea. It is a very excellent gun I will need to make one. It's also nice to see my 1st instructable was mentioned