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Spudguns: Potato Cannon Guide

200 points by cenazoic 2y ago

laweijfmvo 2y ago
These are so fun and easy to get started, but quite challenging to tune and make optimal. The differences between "i just glued a tube together and hair sprayed it a bunch" and having optimal chamber/barrel ratios with a proper air/fuel mix are incredible to see!
rolph 2y ago
PSI rating on your spudgun, shouldnot be overlooked e.g. https://www.klkntv.com/one-man-injured-after-potato-gun-explodes-in-north-lincoln/ https://www.klkntv.com/one-man-injured-after-potato-gun-expl... [2017] [ALSO] dont exceed rated pressure, and know that constant pressure is different than repeated shocks https://www.engineersedge.com/fluid_flow/steel-pipe-pressure-ratings.htm https://www.engineersedge.com/fluid_flow/steel-pipe-pressure... https://www.engineeringtoolbox.com/pvc-cpvc-pipes-pressures-d_796.html https://www.engineeringtoolbox.com/pvc-cpvc-pipes-pressures-...
- indoordin0saur 2y ago
  Has anyone tried supplementing the hairspray with the sort of canned oxygen you can find at ski resorts?
  - temp0826 2y ago
    Not a traditional spud gun, but my father (who has been a welder for his whole life) built a couple differently sized cannons out of aluminum (one fired wine corks and the other was about tennis ball-sized). We used acetylene gas. Honestly kind of terrifying and incredibly dangerous, not recommended. They only come out on independence day.
    - gorgoiler 2y ago
      We built one using acetylene as the source gas generated from calcium carbide and water, ignited by a spark gap from an electric fence. The combustion chamber was a 40 gallon oil drum and the barrel was a 20’ scaffold pole. Round 1 worked a treat, firing a champagne cork sized wooden baton far away into the distance. Round 2 was a disaster. Calcium carbide needs water to react into acetylene. Our method involved putting a few pints of water into the oil drum (on its side), then a few rocks of calcium carbide, then the igniter, and finally the scaffold pole resting under it’s own weight in the small, off centre oil drum aperture. On this second round the end of the pole was accidentally submerged in the puddle and the wooden baton got jammed. This meant the explosion forced water up the gun barrel — a pole just resting there in the mouth of the oil drum — launching the entire pole down the garden. It must have gone a good 50 feet or so. This is a steel javelin weighing a good 30lbs. Round 3 ruptured the oil drum. It sounded like a bomb going off.
  - fkyoureadthedoc 2y ago
    Best my pals and I ever did was engine starter fluid and like 40PSI of air with a duct tape diaphragm to hold the air in. We shot old D batteries wrapped in duct tape out of it. Shot it at a stop sign once and it made a perfect hole with sign peeled back like shooting BB guns at a coke can. The whole thing was stupidly dangerous.
  - gnicholas 2y ago
    I was surprised to see hairspray as the recommended fuel, since that what we used growing up 30 years ago, with no particular engineering expertise. I assumed there would be more advanced options now (if for no other reason, because hairspray smells!)
    - tlavoie 2y ago
      I find the 99% isopropyl alcohol from the pharmacy works well, and it's cheap too. Also, I'd get funny looks buying hairspray, when I have very little hair.
    - petee 2y ago
      Aren't many hairsprays just propane? I think its just a convenient option, otherwise you need a tank and/or a hose of something else
      - deleted 2y ago
        [deleted]
  - annoyingnoob 2y ago
    I always used starting fluid https://www.petes-tools.com/what-is-starter-fluid/ https://www.petes-tools.com/what-is-starter-fluid/
  - petee 2y ago
    Friends and I used MAPP gas mixed with oxygen...had a pretty good kick but you were really just rolling the dice on the ratio
    - no_way_1209567 2y ago
      The way to do this with oxy-fuel is to light the torch, adjust to a neutral flame, then extinguish the flame. The resulting gas coming out of the torch should be pretty close to stoichometric, and should be treated with extreme care.
  - beAbU 2y ago
    Thats how you make a bomb. With pure oxygen you can add /much/ more fuel in, and it detonates rather than deflagrates. Search on youtube for some hydrogeh/oxygen baloon explosions to see what I mean.
- ben1040 2y ago
  30 years ago I was a teenager a friend of mine had a giant plot of empty land in his family, and so we'd go out there and do stupid teenager things things like playing with fireworks and building and shooting potato cannons. We'd discovered dry ice bombs alongside internet plans for potato cannons, and in our infinite wisdom we tried to build a dry ice bomb powered potato cannon. In our mind the sudden increase of air pressure would've sent the payload going ridiculously far. Thankfully when we went to use it the first time, we were smart enough to run as far as we could before it went off. It was far far more pressure than the pipe could handle and it sent little bits of PVC shrapnel flying everywhere.
- KennyBlanken 2y ago
  The rated pressure is for water, and the rating assumes the pipe is in perfect condition. And no, constant vs shock pressure doesn't make it safer. If you nick it, drop it on something, etc - the rating no longer applies. Over the years numerous shops have used PVC pipe "because the compressor only goes up to 100psi and the pipe says 250", that sort of thing...and had the pipework explode and injure/kill people. ~100 psi in a PVC pipe is enough to tear through a sheet of drywall and then fatally injure someone.
spacecadet 2y ago
Made many spud guns as a kid. Spud mortars. It all ended when we fired a rotten crab apple, missed our target, but struck the door of a passing car. The drive chased us through the woods of our property for a while before giving up. Now my buddy works in defense lol.
- dylan604 2y ago
  Now that brings back memories. As a kid, my friends and I knew the woods/creek like the back of our hands, and there were many instances of losing a tail that way. The thing that I found the most interesting was civilian tails seemed much more engaged than the boys in blue ever did. Not sure what the civilian rationale was, but I know the boys in blue didn't want to deal with that much paper work for stupid teenage pranks.
  - rolph 2y ago
    not to avocate violence,but when i was a kid minors were basically immune to prosecution, it was also well known that when a kid got caught doing a bart simpson they would get the hell thrashed out of them until they escaped. ideally that was supposed to quench the problem right there. then again those were the days of a burning bagfull of [X], on the front steps type of pranks.
- dgemm 2y ago
  I feel like we would have been friends in high school
  - spacecadet 2y ago
    8D Do I tell the thermite charge story? No no, not here.
blastro 2y ago
My best friend in grade school was a bit of a deviant and we definitely experimented with these things. Very powerful!
skrbjc 2y ago
I remember the first time we fired one of these. It was dusk and my brothers and I had rigged a remote igniter, and I was elected to hold the cannon itself. We loaded it up, sprayed hairspray in and my brother pushed the igniter. None of us had any idea of how powerful one of these was! The flame that came out the front was over a foot long. We thought maybe the potato would reach the back fence of our yard, but it was launched into oblivion. Luckily our house backed up onto a nature preserve, so at least no-one had a surprise potato land on them. We had much fun that summer iterating on designs and trying every type of various projectile we could find.
- lagniappe 2y ago
  You probably started a small field of potatoes if it stayed mostly intact!
- mavamaarten 2y ago
  I remember shooting a potato into a wall, hoping to laugh at the potato becoming mush. There was no mush. Only potato dust.
  - rolph 2y ago
    you have to freeze the potato for more "lolz"
    - RicoElectrico 2y ago
      If you freeze it, it won't cut to the diameter of the barrel.
      - rolph 2y ago
        you make a number of spud pellets, you freeze them after
        BizarroLand 2y ago
        I like how when someone offered an idea that turns a mildly dangerous toy into a decidedly lethal weapon, rather than dissuade others of the terrible notion we went into problem solving mode to increase reliability, quality, and to minimize the potential hassles inherent with the lethal solution.
deleted 2y ago
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lowdest 2y ago
The links on the 404 page bought me to some very nostalgic feeling pages. Very late-90s aesthetic. An MP3 directory index. A webcam with a frame that hasn't refreshed since 2009. I miss the old internet.
- readingnews 2y ago
  So many dead links... so many links going to AOL or CNN or domain-squatters. Heck a lot of links on the first page are empty. On the flip side, like so many others here, I had a friend who went overboard with his. Automatic reloading systems, piezo trigger so you did not need lighters and such, scopes, automatic cutting devices for the spuds. He tore it apart after a spud went through both sides of a car (it was a junk car he was intending to shoot) and ended up "who knows where" on the other side.
jasonpeacock 2y ago
> Took a bit of doing to code the design by hand in Notepad with all the nested tables originally, however with Dreamweaver it's only taken a few hours, not weeks. So many memories...
Certified 2y ago
I wish Supah Valves [1] were still available so I could recommend them. They use a smaller sprinkler valve as a pilot to move a much larger piston based valve _very_ quickly. That lets a lot more of your reservoir pressure get to the barrel before your projectile has shot out the end. The result? More range. More grins. [1] https://www.spudtech.com/store/index.php?main_page=product_info&cPath=8&products_id=12 https://www.spudtech.com/store/index.php?main_page=product_i...
lenerdenator 2y ago
This is going to be the last week someone in this thread has all ten of their fingers, working ears, or both.
- kedarkhand 2y ago
  You can bet it is going to be me!
jetrink 2y ago
I was doing ecological work in a lake when we came under spudgun fire. Someone (kids?) began slowly firing from a distant treeline on the side of one of the hills that surrounded the lake. I knew the distinctive thump, so I was looking out for the first splash, which ended up being much closer than I expected it to be! I had assumed they would be aiming somewhere else. I informed my shipmates that we were under attack and we rowed to shore as fast as possible. They got in about three or four shots, but we escaped injury and no one was ever caught.
- umvi 2y ago
  I wonder if most of the dangerous levels of kinetic energy in the potato would have bled off from air resistance though by the time it reached your ship. Sort of like how you can shoot a shotgun at animals that are way off in the distance without the BBs being able to penetrate skin because they've bled off too much energy to air resistance.
  - lazide 2y ago
    A potato likely has a pretty good ballistic co-efficient due to its mass to surface area ratio. It would be even better if it was denser of course, but if a nice green one, it’s still pretty dense. That’s why artillery can hit 20-30 miles away even though muzzle velocities are roughly the same as a rifle, which would be lucky to go a couple miles even if fired at the same angle.
  - beAbU 2y ago
    Throw a potato as high up in the air as you can, and catch it with your face.
- deleted 2y ago
  [deleted]
- lukan 2y ago
  And there was no second part with sneaking through the forest, surrounding and confronting them? Maybe you had more important things to do, but this is what I would have done. Playing artillery on humans is not a prank I think.
cantSpellSober 2y ago
>> sees link to slashdot in the header Can we add (2008) to the title please?
- gnicholas 2y ago
  The site is old-school, but don't "(year)" markings only go on articles that were published on a particular date, as opposed to websites that are modified over time?
  - cantSpellSober 2y ago
    I don't see any updates in the archive since then
    - randomsolutions 2y ago
      spud guns are timeless
epiccoleman 2y ago
William Gurstelle's Backyard Ballistics and The Art of the Catapult were two extremely influential books in my development as a young engineering minded person. Countless hours of fun were had experimenting with spud guns of varying designs.
Ductapemaster 2y ago
Ahh good memories. Over the summer in college, I made a pretty advanced propane-powered one with an integral mixing fan for the chamber and an cheap taser for electronic ignition. Fired every time. Had great fun with my roommates shooting them out into the ocean off our balcony (UCSB — how lucky we were!). Sadly it was confiscated by the police shortly after. They drove by me loading it into my car at night. The 8ft barrel was fairly obvious...
Qworg 2y ago
If this is of interest, be sure to check out https://www.spudfiles.com/ https://www.spudfiles.com/ - multiple types and versions of cannons, including very clever single inlet piston style ones that shoot incredibly far. Here's an example: https://nighthawkinlight.wonderhowto.com/how-to/make-powerful-pvc-air-cannon-with-coaxial-piston-valve-0141605/ https://nighthawkinlight.wonderhowto.com/how-to/make-powerfu...
ubj 2y ago
Potato cannons first inspired my love of physics. In high school I was amazed when I discovered that I could fire one vertically, time how long it took for the potato to hit the ground, and then mathematically reconstruct both the potato's exit velocity and the maximum height it reached. It felt like magic. I ended up performing a science fair project on the effect of the potato cannon barrel length on the potato's max speed and height. (My experiments also led to a short encounter with the police, but that's a different story.)
- NortySpock 2y ago
  > a science fair project on the effect of the potato cannon barrel length on the potato's max speed and height Don't just leave us hanging out here, what was the optimal barrel length for your chamber volume?
dtx1 2y ago
Fun Fact: There are Countries where Spudguns are illegal and treated like a weapons charge. Germany being one of them.
- mschuster91 2y ago
  Fellow German here, I think this actually makes sense. Primarily, unlike the US we just lack the void space. Even if you're in a "rural" area you'll still annoy dozens of people firing a spud gun with compressed air, and one fired with explosives will be thought of as someone firing guns - which is damn rare to hear, only during hunting season in the forests. The same argument also holds valid for a number of other things common in the US but not in Germany like keeping entire residential properties filled with cars in various states of (dis)repair, firing guns in general, producing nuclear waste, flying experimental planes, starting planes and choppers from anywhere else than a licensed airstrip, ...
  - jpt4 2y ago
    It makes no objective sense at all, and merely reflects hypersensitive German policy regarding civilian ownership of anything resembling the means of force application.
    - mschuster91 2y ago
      It's not just Germany that is very sensitive towards guns - that's an attitude prevalent on the entire continent, maybe except the Balkans and Switzerland. The UK has even stricter regulations on guns, and not just guns but also other kinds of weapons like knives.
    - numpad0 2y ago
      No, it's the US gun control that is abnormally relaxed compared to the rest of the world, especially among developed nations. Not the other way around. The reason why it's never gets fixed for the US must be that the US also has total global socioeconomic dominance and none of you guys want to rock the boat and accidentally fix that too in the process.
GaryNumanVevo 2y ago
Here are some good tips for a spud gun: - Schedule 80 PVC where possible - Use anti-static spray instead of hair spray, it's cheaper and doesn't leave a tacky combustion chamber - Put a small PC fan into the combustion chamber to mix the fuel and air, this will ensure you get a fuller combustion. If you're an adult, you can make one out of metal pipe and use an oxy acetylene torch to fuel it. Perfect stoichometric ratio, very very energetic!
rolph 2y ago
IANAL : Potato cannon legality https://en.wikipedia.org/wiki/Potato_cannon_legality https://en.wikipedia.org/wiki/Potato_cannon_legality in US: bare minimum it is a dangerous device as in pelletgun or archery equipment. how/why its used, as well as ballistic features may cross a threshold. if you construct a firearm, you must not have legal restrictions on ownership. if the projectile of a firearm,is an actual .50calibre or greater,that is a destructive device and you must be rigorously vetted to construct or own that
- msandford 2y ago
  I just read the US section and it seems to contradict what you just stated above. If you use incendiary tennis balls it qualifies as a "destructive device" but then it's not really a potato cannon anymore. It also says if you use compressed air that completely disqualifies it from "destructive device" potential classification in the eyes of the law.
  - rolph 2y ago
    take note that dangerous device, and destructive device are different classifications. "it must be muzzle loaded, not rifled, and not use any projectile which is intended to be used as a weapon." compressed gas propulsion is not a firearm, unless it [gas] is produced by combustion or explosion of a chemical [incl. propane. ] magazine or breech loading, rifled barrel, a cartridge holding projectile, and charge as part of design will seal the deal for definition as firearm.
- 01100011 2y ago
  A friend of mine who is a former JPL mech engineer was working on an amazing, high pressure golf ball cannon until his city issued him a citation for his smaller gun. That pretty much ended his foray into pneumatic weapons. Shame, because his gun looked amazing. He even custom built a road case to store it all. Guy is on the spectrum and has ADHD which has resulted in some amazing, but completely over-engineered, work over the years. He engineered his own gluelam support beams in his garage which could lift a car. He rewired his house using all stranded wire, bus bars and crimp connectors and it was all mil-spec.
ugh123 2y ago
Can parts of these be 3d printed?
- mulmen 2y ago
  Maybe external mounting brackets? Say for the ignition system or maybe a sight of some kind? I wouldn’t trust a 3D print for any of the high pressure stuff but I don’t actually know if that’s feasible. I’d love to find out I’m wrong.
- wepple 2y ago
  Not strong enough
- annoyingnoob 2y ago
  If you like shrapnel.
- AngryData 2y ago
  Theoretically yes with the right materials, but realistically 3d printing is too sensitive to safely and reliably print pressure vessels of any significant size without putting yourself in danger. Some plastics are going to have weak points between layers that could splint apart instantly and without warning, and other plastics that don't have that problem are often brittle and could throw large chunks. But pressure rated plastic pipe extrusions are fairly cheap (just be aware some are only rated for water pressure, not air pressure). And if you need something small and lightweight, pop bottles can hold up to 100 PSI. Tom Stanton's channel on youtube does a bunch of air powered RC planes and stuff using pop bottles to hold air.
xivzgrev 2y ago
wow this is a fancy one. the one friends & I built in high school was more simple 1) a narrow tube to put potato in 2) a larger tube for firing chamber with a screw cap 3) a sealed hole cut into firing chamber for a lighter put potato in one end, unscrew the cap, spray hairspray liberally inside, screw cap back on, aim, and fire
wepple 2y ago
I built the fauxtato a while back; a small capsule to simulate a potato but with a 32g accelerometer (8g is wildly insufficient) and WiFi to be able to log data and make basic analyses about different cannon & fuel usage. Really interested run some tests based on things in this thread, like different propellants.
- wepple 2y ago
  Correction: it was a ADXL375 200g sensor
  - nehal3m 2y ago
    That is amazing. Can you tell us if the potato referred to in this comment [0] could have done serious damage? [0] https://news.ycombinator.com/item?id=40798939#40812811 https://news.ycombinator.com/item?id=40798939#40812811
    - wepple 2y ago
      That’s really interesting, I haven’t spent much time looking at the data from the landing impact. I’m also not confident in my skills to translate G-forces into velocities or such. I guess it depends largely on what type of surface it lands on? You’ve definitely got me thinking now. There’s a bunch of ways I could roughly come up with a model for this.
deleted 2y ago
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flyinghamster 2y ago
A buddy of mine had a compressed-air spud gun that he made from an air compressor tank, a ball valve, and a length of 3" copper pipe. That thing could put dents in a 1/4" thick scrap steel plate.
deleted 2y ago
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jprd 2y ago
I have NEVER EVER used one of these to fire across a US Interstate at night (successfully). Mind your PSI and test your ballistics prior to using it for more, artful, purposes.
mejare777 2y ago
[flagged]
rehevkor5 2y ago
Relevant: this video with some info about dangers/safety especially related to non-pressure-rated PVC: https://www.youtube.com/watch?v=KqstP9ics2A https://www.youtube.com/watch?v=KqstP9ics2A
reducesuffering 2y ago
Silicon Valley, the show, is a documentary. https://youtu.be/Q1QPXyebhiY?si=5YWYlCuI2aJ2fu-l&t=474 https://youtu.be/Q1QPXyebhiY?si=5YWYlCuI2aJ2fu-l&t=474
gnarcoregrizz 2y ago
I made few of these when I was a kid. My pièce de résistance was a 10' 'coaxial piston launcher'. It scared the bejeezus out of most people... I usually shot ice slugs, which would throw a hole in a piece of plywood at 50 psi. A golf ball with a chipped off shell fits perfectly in a 2" PVC barrel. The problem with chipping off the shell (along with an unrifled barrel) is that it makes it like a knuckleball - you have no idea where it's going to go. They would curve violently in any direction. One of the few times I shot one of these, it curved directly upwards, and I'm guessing landed a half a mile or so away. Hopefully it didn't hit anyone or anything. That was the last time I shot it.
deleted 2y ago
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eigenvalue 2y ago
I used to think these were really cool and harmless fun as a teenager. Then at college, some guys I knew made one (and they weren’t dumb at all, pretty competent people). They were firing it near where people were sitting on the lawn and it suddenly shattered, sending sharp jagged pieces of PVC flying. One of the pieces hit a girl sitting nearby and gave her a nasty cut near her eye. Her face was covered in blood and it was totally horrific for her and everyone else. It made me realize that the fun of the activity was just significantly outweighed by the possible safety downside. It could have been so much worse, too— she could have been blinded instead of just gotten a nasty scar on her face.
- spike021 2y ago
  I think the key is using them in an open space away from people and where you can have some measure of safety. My friends would use theirs in an uninhabited valley off a ridge.
  - eigenvalue 2y ago
    Yes but even then the person firing it is at risk. At a minimum you should use serious eye and face protection.
    - macNchz 2y ago
      When my friends and I made these 20 years ago we leaned into the "cannon" vibe and mounted them on sawhorses held down with sandbags, then the ignition was on a wire so you could step back to fire it. At the time I think it was... not about safety so much as it just seemed cool to do it like that, but I guess that's one way not to actually be holding the thing while it fires.
      - lazide 2y ago
        Notably, cannons also used to sometimes explode randomly when fired.
- petee 2y ago
m-i-l 2y ago
Surprised to see people talking about spudguns firing whole potatoes! I didn't even know that was a thing. The spudgun I had when I was young just fired small parts of a potato, with a whole potato enough to last for ages. I think it was the Lone Star Spudmatic. Not only safer but less wasteful. FWIW, it looks like Wikipedia differentiates the smaller spudgun from the larger potato cannon: https://en.wikipedia.org/wiki/Spud_gun https://en.wikipedia.org/wiki/Spud_gun vs https://en.wikipedia.org/wiki/Potato_cannon https://en.wikipedia.org/wiki/Potato_cannon
- spjwebster 2y ago
  Yours is definitely the spud gun I remember, and I suspect that's true for most folks of a particular age from the UK: a small die cast red gun and a monster potato to feed it ammunition. If we're talking home made back garden arsenal, the go-to for my generation was the peg gun: https://www.instructables.com/A-Great-Peg-Gun/ https://www.instructables.com/A-Great-Peg-Gun/, which is, in retrospect, absolutely irresponsibly lethal with the right tension elastic bands.
ElCapitanMarkla 2y ago
This takes me back. Dad was a plumber so I had ready access to all the gear for this growing up. I was introduced to it when he turned up at home one day with one, we launched a few spuds into the neighbouring paddock using Mum's hairspray. I was about 13 at the time so I spent hours on this site planning different launchers. Managed to blow my friend's Dad's air compressor up while firing a smaller one. I don't know how the hell I still have all my fingers / eyes but I had some fun :)
vlachen 2y ago
In the summer of 2004 I was enjoying the mountainous view and ample sun of Kandahar, Afghanistan. It was there, eating one of my allotted MREs, that I noticed the MRE heater was printed in large letters "Do not expose to flame." Being a bored jarhead, I couldn't help but try and figure out why. Being able to rub a few brain cells together, I thought about how the heaters are activated by the addition of water. Since water is hydrogen and oxygen, I was willing to bet that those were some of the reaction products. I never bothered to look it up, but I did find that whatever was coming out with the steam was also quite flammable. Once that was proven, I recalled that recently a contractor had dug a well near our work site. I ambled over and found a 3 foot long, ~3 inch diameter steel pipe that had a 90 degree elbow with a quick release cap. All that was required after that was a touch hole, added with a drill, some MRE heaters, and projectiles. Potatoes were not available there, but fruit like oranges and pears were. I started with an orange and just jammed it into the very end of the barrel, it was too big to go all the way in, and went for it. The distance was laughable, 1 or 2 feet, but the sound? Everyone came running out of the work center tents because they thought I had just loosed a round from my weapon. After being called an idiot by the local Lieutenant, I switch to only pears, which were easy to jam in hard enough to cut the excess off. At this point, I was lobbing pears across the perimeter road, into the scrub / minefield outside the wire. Never found a mine with it though. All my fun ended one faithful day when I accidentally dropped a pear in front of a Romanian MP truck on patrol around the perimeter. The 50 cal on top turned to point at me, I dropped the pear cannon and walked away, never to return.
- bityard 2y ago
  > The 50 cal on top turned to point at me, I dropped the pear cannon and walked away Pretty sure I would have dropped something else and RUN away
  - vlachen 2y ago
    Kind of like a cat, I didn't want to tickle their predator instinct. If I was on the other side of the wire, it'd probably be a different story. Or no story.
- 2y ago
gothink 2y ago
I had an amazing science teacher in high school who brought a potato cannon he had built into to class to show us. Except he called it a "sock cannon" and had loaded it with a large tube sock that he had rolled up. He explained how it worked, how he built it from a few basic plumbing parts anyone could get at the hardware store, how the fuel was just hairspray and how we definitely shouldn't build one ourselves. Naturally, I went home and decided to construct a much bigger version of the one he showed us. After convincing my parents to drive me to the hardware store, I picked out what I needed -- including 7 feet of PVC. The clerk immediately figured out what I was building and that was the first time I heard the term potato cannon. They seemed concerned that my mom was on board with the whole thing, but I stuck to my guns and said it was a science project and was for shooting socks. I had figured I could wrap the sock around a smaller projectile, but that clerk made me realize I didn't even need the sock. My friend and I put it all together pretty quickly the next day and set it up in my backyard for testing. I think we probably started with socks, but I honestly can't recall. What I do remember is taking a hacky-sack I had lying around that fit perfectly into the barrel to try and fire it at our back fence. We were using a piezo igniter from a lighter I had disassembled, and it took some trial and error to get the fuel to air mixture just right. It took both of us to operate: one person aimed the barrel, the other operated the trigger. This time, I was aiming and he was lighting. But it just wasn't lighting... so I turned around to try and help and BOOM the cannon went off like, well, a cannon. Except I wasn't pointing at the fence anymore, but well above it. The hacky-sack tore through the branches of several trees before exploding on the metal siding of the house on the opposite side of our block. The sound could probably be heard for blocks. We both just looked at each other with a mixture of delight and panic before immediately running back into my house. We saw someone come out of the house we hit looking utterly confused, trying to figure out what just happened. We started laughing uncontrollably, realizing how close we were to causing a lot of damage, or possibly injuring someone. Luckily, nothing every came of that incident, and we made sure later tests were done in a nearby park. We never did attempt to put an actual potato in the thing. Perhaps 7 feet was a little overkill... PS - Dr. Vince, if you're out there, thank you for being one of the best teachers I've ever had. I'll never forget that class, or that "sock cannon"!
tonetegeatinst 2y ago
Iv been interested in this on and off for a few years. My most sunkworks idea was based of atechnology connections video, to use a stocheometric ratio of liquid hydrogen and liquid oxygen, dump it into a steel pressure chamber....then let the liquids convert into a gas, then detonate the mixed gas using a high voltage arc. The detonation force blows a burst disk open and blasts the projectile slug forward at what I hoped to be hypersonic speeds. Never really got to into it though cuz I'd need some machining equipment and a budget for the materials
fallinditch 2y ago
Adam Savage made something similar, with compressed air, for the Slow Mo Guys - https://youtu.be/w9i9rwg1L_A?feature=shared https://youtu.be/w9i9rwg1L_A?feature=shared
alexpotato 2y ago
My username comes from the fact that I built and sold potato guns back when I was in high school. I should really write up a thread on some of the stories from those days.
- hyperdimension 2y ago
  Please do! Quirky fun personal websites used to be what the Internet was all about! You have at least one guaranteed reader.
austinkurpuis 2y ago
This website was my dad’s second bible when I was a kid. He went down the rabbit hole and ended up building a massive steel spud gun that had a 10 foot copper barrel. That thing could throw a potato close to a quarter mile. Some great childhood memories right there.
jschveibinz 2y ago
Related vegetable ballistics: Punkin' Chunkin' Championship https://www.punkinchunkin.com/ https://www.punkinchunkin.com/
chasd00 2y ago
I made something like this in HS out of coffee cans with the bottoms cut out in half moon shapes. Then I duct taped them all together and would put rubbing alcohol in the top, shake it up and let it evaporate, and ignite from a nail hole in the bottom can. I could launch Gatorade bottles filled with water about 100 yards. It blew up once and I never bothered to put it back together. Plus my mom was hysterical.
fullspectrumdev 2y ago
Built a bunch of these - both combustion and “compressed air” based as a teenager, with varying results. I had been inspired by a “science demonstration” at a science fair where “Doctor Bunhead” (of “Brainiac” TV fame) shot one through a tennis racquet to make “instant chips”.
demondemidi 2y ago
Back in the late 80s in college a guy in my dorm made a combustion gun. We were watching him shooting spuds from the dorm lawn into the air not caring where it landed. Later that evening he was arrested because one spud gave the parent of a visiting student and orbital fracture 300 yards away and her eyeball literally fell out. Since he was doing it in front of the whole dorm the police had no trouble finding him. He lasted only two weeks in college no idea what happened after he was arrested. Be smart if you make one of these things they are super dangerous.
jsvaughan 2y ago
Good book on this and similar subjects - Backyard Ballistics: Build Potato Cannons, Paper Match Rockets, Cincinnati Fire Kites, Tennis Ball Mortars, and More Dynamite Devices https://www.amazon.com/Backyard-Ballistics-Cannons-Cincinnati-Dynamite/dp/1613740646 https://www.amazon.com/Backyard-Ballistics-Cannons-Cincinnat...
cyrialize 2y ago
A fond memory I had as a teenager was making a potato cannon with my brother and dad. The cannon was in a J shape, where the end of the J had a cap for spraying in fuel - like propane or hairspray. Near the end of the J shape we cut a hole to put in an elongated lighter. This went against the design of the video we watched - the video suggested taking the ignition stuff out of the lighter and making it part of the canon. Cutting a hole and just gluing a lighter was the easiest option... but also caused a lot of problems - namely with ignition. During the building of this, right as my mom came home, I looked down the PVC pipe (there was nothing in it thankfully) and asked my brother to click the lighter so that I could check to see if it was lighting or not. My father was not in the room. This ignited the residual fuel in the pipe and burned ALL of the eyelashes off of my left eye. My father came running in and started to scold us, and then my mom came in the room asking what happened. We all hid everything, because my dad didn't want to get into trouble either. We shot many potatoes that summer, and the whole experience made me realize how useful eyelashes are.
oldgregg 2y ago
ted kaczynski alternate timeline

200 points by cenazoic 2y ago

These are so fun and easy to get started, but quite challenging to tune and make optimal. The differences between "i just glued a tube together and hair sprayed it a bunch" and having optimal chamber/barrel ratios with a proper air/fuel mix are incredible to see!

rolph 2y ago

PSI rating on your spudgun, shouldnot be overlooked e.g. https://www.klkntv.com/one-man-injured-after-potato-gun-explodes-in-north-lincoln/ https://www.klkntv.com/one-man-injured-after-potato-gun-expl... [2017] [ALSO] dont exceed rated pressure, and know that constant pressure is different than repeated shocks https://www.engineersedge.com/fluid_flow/steel-pipe-pressure-ratings.htm https://www.engineersedge.com/fluid_flow/steel-pipe-pressure... https://www.engineeringtoolbox.com/pvc-cpvc-pipes-pressures-d_796.html https://www.engineeringtoolbox.com/pvc-cpvc-pipes-pressures-...

indoordin0saur 2y ago
Has anyone tried supplementing the hairspray with the sort of canned oxygen you can find at ski resorts?
- temp0826 2y ago
  Not a traditional spud gun, but my father (who has been a welder for his whole life) built a couple differently sized cannons out of aluminum (one fired wine corks and the other was about tennis ball-sized). We used acetylene gas. Honestly kind of terrifying and incredibly dangerous, not recommended. They only come out on independence day.
  - gorgoiler 2y ago
    We built one using acetylene as the source gas generated from calcium carbide and water, ignited by a spark gap from an electric fence. The combustion chamber was a 40 gallon oil drum and the barrel was a 20’ scaffold pole. Round 1 worked a treat, firing a champagne cork sized wooden baton far away into the distance. Round 2 was a disaster. Calcium carbide needs water to react into acetylene. Our method involved putting a few pints of water into the oil drum (on its side), then a few rocks of calcium carbide, then the igniter, and finally the scaffold pole resting under it’s own weight in the small, off centre oil drum aperture. On this second round the end of the pole was accidentally submerged in the puddle and the wooden baton got jammed. This meant the explosion forced water up the gun barrel — a pole just resting there in the mouth of the oil drum — launching the entire pole down the garden. It must have gone a good 50 feet or so. This is a steel javelin weighing a good 30lbs. Round 3 ruptured the oil drum. It sounded like a bomb going off.
- fkyoureadthedoc 2y ago
  Best my pals and I ever did was engine starter fluid and like 40PSI of air with a duct tape diaphragm to hold the air in. We shot old D batteries wrapped in duct tape out of it. Shot it at a stop sign once and it made a perfect hole with sign peeled back like shooting BB guns at a coke can. The whole thing was stupidly dangerous.
- gnicholas 2y ago
  I was surprised to see hairspray as the recommended fuel, since that what we used growing up 30 years ago, with no particular engineering expertise. I assumed there would be more advanced options now (if for no other reason, because hairspray smells!)
  - tlavoie 2y ago
    I find the 99% isopropyl alcohol from the pharmacy works well, and it's cheap too. Also, I'd get funny looks buying hairspray, when I have very little hair.
  - petee 2y ago
    Aren't many hairsprays just propane? I think its just a convenient option, otherwise you need a tank and/or a hose of something else
    - deleted 2y ago
      [deleted]
- annoyingnoob 2y ago
  I always used starting fluid https://www.petes-tools.com/what-is-starter-fluid/ https://www.petes-tools.com/what-is-starter-fluid/
- petee 2y ago
  Friends and I used MAPP gas mixed with oxygen...had a pretty good kick but you were really just rolling the dice on the ratio
  - no_way_1209567 2y ago
    The way to do this with oxy-fuel is to light the torch, adjust to a neutral flame, then extinguish the flame. The resulting gas coming out of the torch should be pretty close to stoichometric, and should be treated with extreme care.
- beAbU 2y ago
  Thats how you make a bomb. With pure oxygen you can add /much/ more fuel in, and it detonates rather than deflagrates. Search on youtube for some hydrogeh/oxygen baloon explosions to see what I mean.
ben1040 2y ago
30 years ago I was a teenager a friend of mine had a giant plot of empty land in his family, and so we'd go out there and do stupid teenager things things like playing with fireworks and building and shooting potato cannons. We'd discovered dry ice bombs alongside internet plans for potato cannons, and in our infinite wisdom we tried to build a dry ice bomb powered potato cannon. In our mind the sudden increase of air pressure would've sent the payload going ridiculously far. Thankfully when we went to use it the first time, we were smart enough to run as far as we could before it went off. It was far far more pressure than the pipe could handle and it sent little bits of PVC shrapnel flying everywhere.
KennyBlanken 2y ago
The rated pressure is for water, and the rating assumes the pipe is in perfect condition. And no, constant vs shock pressure doesn't make it safer. If you nick it, drop it on something, etc - the rating no longer applies. Over the years numerous shops have used PVC pipe "because the compressor only goes up to 100psi and the pipe says 250", that sort of thing...and had the pipework explode and injure/kill people. ~100 psi in a PVC pipe is enough to tear through a sheet of drywall and then fatally injure someone.

spacecadet 2y ago

Made many spud guns as a kid. Spud mortars. It all ended when we fired a rotten crab apple, missed our target, but struck the door of a passing car. The drive chased us through the woods of our property for a while before giving up. Now my buddy works in defense lol.

dylan604 2y ago
Now that brings back memories. As a kid, my friends and I knew the woods/creek like the back of our hands, and there were many instances of losing a tail that way. The thing that I found the most interesting was civilian tails seemed much more engaged than the boys in blue ever did. Not sure what the civilian rationale was, but I know the boys in blue didn't want to deal with that much paper work for stupid teenage pranks.
- rolph 2y ago
  not to avocate violence,but when i was a kid minors were basically immune to prosecution, it was also well known that when a kid got caught doing a bart simpson they would get the hell thrashed out of them until they escaped. ideally that was supposed to quench the problem right there. then again those were the days of a burning bagfull of [X], on the front steps type of pranks.
dgemm 2y ago
I feel like we would have been friends in high school
- spacecadet 2y ago
  8D Do I tell the thermite charge story? No no, not here.

blastro 2y ago

My best friend in grade school was a bit of a deviant and we definitely experimented with these things. Very powerful!

skrbjc 2y ago

I remember the first time we fired one of these. It was dusk and my brothers and I had rigged a remote igniter, and I was elected to hold the cannon itself. We loaded it up, sprayed hairspray in and my brother pushed the igniter. None of us had any idea of how powerful one of these was! The flame that came out the front was over a foot long. We thought maybe the potato would reach the back fence of our yard, but it was launched into oblivion. Luckily our house backed up onto a nature preserve, so at least no-one had a surprise potato land on them. We had much fun that summer iterating on designs and trying every type of various projectile we could find.

lagniappe 2y ago
You probably started a small field of potatoes if it stayed mostly intact!
mavamaarten 2y ago
I remember shooting a potato into a wall, hoping to laugh at the potato becoming mush. There was no mush. Only potato dust.
- rolph 2y ago
  you have to freeze the potato for more "lolz"
  - RicoElectrico 2y ago
    If you freeze it, it won't cut to the diameter of the barrel.
    - rolph 2y ago
      you make a number of spud pellets, you freeze them after
      - BizarroLand 2y ago
        I like how when someone offered an idea that turns a mildly dangerous toy into a decidedly lethal weapon, rather than dissuade others of the terrible notion we went into problem solving mode to increase reliability, quality, and to minimize the potential hassles inherent with the lethal solution.

deleted 2y ago

[deleted]

lowdest 2y ago

The links on the 404 page bought me to some very nostalgic feeling pages. Very late-90s aesthetic. An MP3 directory index. A webcam with a frame that hasn't refreshed since 2009. I miss the old internet.

readingnews 2y ago
So many dead links... so many links going to AOL or CNN or domain-squatters. Heck a lot of links on the first page are empty. On the flip side, like so many others here, I had a friend who went overboard with his. Automatic reloading systems, piezo trigger so you did not need lighters and such, scopes, automatic cutting devices for the spuds. He tore it apart after a spud went through both sides of a car (it was a junk car he was intending to shoot) and ended up "who knows where" on the other side.

jasonpeacock 2y ago

> Took a bit of doing to code the design by hand in Notepad with all the nested tables originally, however with Dreamweaver it's only taken a few hours, not weeks. So many memories...

Certified 2y ago

I wish Supah Valves [1] were still available so I could recommend them. They use a smaller sprinkler valve as a pilot to move a much larger piston based valve _very_ quickly. That lets a lot more of your reservoir pressure get to the barrel before your projectile has shot out the end. The result? More range. More grins. [1] https://www.spudtech.com/store/index.php?main_page=product_info&cPath=8&products_id=12 https://www.spudtech.com/store/index.php?main_page=product_i...

lenerdenator 2y ago

This is going to be the last week someone in this thread has all ten of their fingers, working ears, or both.

kedarkhand 2y ago
You can bet it is going to be me!

jetrink 2y ago

I was doing ecological work in a lake when we came under spudgun fire. Someone (kids?) began slowly firing from a distant treeline on the side of one of the hills that surrounded the lake. I knew the distinctive thump, so I was looking out for the first splash, which ended up being much closer than I expected it to be! I had assumed they would be aiming somewhere else. I informed my shipmates that we were under attack and we rowed to shore as fast as possible. They got in about three or four shots, but we escaped injury and no one was ever caught.

umvi 2y ago
I wonder if most of the dangerous levels of kinetic energy in the potato would have bled off from air resistance though by the time it reached your ship. Sort of like how you can shoot a shotgun at animals that are way off in the distance without the BBs being able to penetrate skin because they've bled off too much energy to air resistance.
- lazide 2y ago
  A potato likely has a pretty good ballistic co-efficient due to its mass to surface area ratio. It would be even better if it was denser of course, but if a nice green one, it’s still pretty dense. That’s why artillery can hit 20-30 miles away even though muzzle velocities are roughly the same as a rifle, which would be lucky to go a couple miles even if fired at the same angle.
- beAbU 2y ago
  Throw a potato as high up in the air as you can, and catch it with your face.
deleted 2y ago
[deleted]
lukan 2y ago
And there was no second part with sneaking through the forest, surrounding and confronting them? Maybe you had more important things to do, but this is what I would have done. Playing artillery on humans is not a prank I think.

cantSpellSober 2y ago

>> sees link to slashdot in the header Can we add (2008) to the title please?

gnicholas 2y ago
The site is old-school, but don't "(year)" markings only go on articles that were published on a particular date, as opposed to websites that are modified over time?
- cantSpellSober 2y ago
  I don't see any updates in the archive since then
  - randomsolutions 2y ago
    spud guns are timeless

epiccoleman 2y ago

William Gurstelle's Backyard Ballistics and The Art of the Catapult were two extremely influential books in my development as a young engineering minded person. Countless hours of fun were had experimenting with spud guns of varying designs.

Ductapemaster 2y ago

Ahh good memories. Over the summer in college, I made a pretty advanced propane-powered one with an integral mixing fan for the chamber and an cheap taser for electronic ignition. Fired every time. Had great fun with my roommates shooting them out into the ocean off our balcony (UCSB — how lucky we were!). Sadly it was confiscated by the police shortly after. They drove by me loading it into my car at night. The 8ft barrel was fairly obvious...

Qworg 2y ago

If this is of interest, be sure to check out https://www.spudfiles.com/ https://www.spudfiles.com/ - multiple types and versions of cannons, including very clever single inlet piston style ones that shoot incredibly far. Here's an example: https://nighthawkinlight.wonderhowto.com/how-to/make-powerful-pvc-air-cannon-with-coaxial-piston-valve-0141605/ https://nighthawkinlight.wonderhowto.com/how-to/make-powerfu...

ubj 2y ago

Potato cannons first inspired my love of physics. In high school I was amazed when I discovered that I could fire one vertically, time how long it took for the potato to hit the ground, and then mathematically reconstruct both the potato's exit velocity and the maximum height it reached. It felt like magic. I ended up performing a science fair project on the effect of the potato cannon barrel length on the potato's max speed and height. (My experiments also led to a short encounter with the police, but that's a different story.)

NortySpock 2y ago
> a science fair project on the effect of the potato cannon barrel length on the potato's max speed and height Don't just leave us hanging out here, what was the optimal barrel length for your chamber volume?

dtx1 2y ago

Fun Fact: There are Countries where Spudguns are illegal and treated like a weapons charge. Germany being one of them.

mschuster91 2y ago
Fellow German here, I think this actually makes sense. Primarily, unlike the US we just lack the void space. Even if you're in a "rural" area you'll still annoy dozens of people firing a spud gun with compressed air, and one fired with explosives will be thought of as someone firing guns - which is damn rare to hear, only during hunting season in the forests. The same argument also holds valid for a number of other things common in the US but not in Germany like keeping entire residential properties filled with cars in various states of (dis)repair, firing guns in general, producing nuclear waste, flying experimental planes, starting planes and choppers from anywhere else than a licensed airstrip, ...
- jpt4 2y ago
  It makes no objective sense at all, and merely reflects hypersensitive German policy regarding civilian ownership of anything resembling the means of force application.
  - mschuster91 2y ago
    It's not just Germany that is very sensitive towards guns - that's an attitude prevalent on the entire continent, maybe except the Balkans and Switzerland. The UK has even stricter regulations on guns, and not just guns but also other kinds of weapons like knives.
  - numpad0 2y ago
    No, it's the US gun control that is abnormally relaxed compared to the rest of the world, especially among developed nations. Not the other way around. The reason why it's never gets fixed for the US must be that the US also has total global socioeconomic dominance and none of you guys want to rock the boat and accidentally fix that too in the process.

GaryNumanVevo 2y ago

Here are some good tips for a spud gun: - Schedule 80 PVC where possible - Use anti-static spray instead of hair spray, it's cheaper and doesn't leave a tacky combustion chamber - Put a small PC fan into the combustion chamber to mix the fuel and air, this will ensure you get a fuller combustion. If you're an adult, you can make one out of metal pipe and use an oxy acetylene torch to fuel it. Perfect stoichometric ratio, very very energetic!

rolph 2y ago

IANAL : Potato cannon legality https://en.wikipedia.org/wiki/Potato_cannon_legality https://en.wikipedia.org/wiki/Potato_cannon_legality in US: bare minimum it is a dangerous device as in pelletgun or archery equipment. how/why its used, as well as ballistic features may cross a threshold. if you construct a firearm, you must not have legal restrictions on ownership. if the projectile of a firearm,is an actual .50calibre or greater,that is a destructive device and you must be rigorously vetted to construct or own that

msandford 2y ago
I just read the US section and it seems to contradict what you just stated above. If you use incendiary tennis balls it qualifies as a "destructive device" but then it's not really a potato cannon anymore. It also says if you use compressed air that completely disqualifies it from "destructive device" potential classification in the eyes of the law.
- rolph 2y ago
  take note that dangerous device, and destructive device are different classifications. "it must be muzzle loaded, not rifled, and not use any projectile which is intended to be used as a weapon." compressed gas propulsion is not a firearm, unless it [gas] is produced by combustion or explosion of a chemical [incl. propane. ] magazine or breech loading, rifled barrel, a cartridge holding projectile, and charge as part of design will seal the deal for definition as firearm.
01100011 2y ago
A friend of mine who is a former JPL mech engineer was working on an amazing, high pressure golf ball cannon until his city issued him a citation for his smaller gun. That pretty much ended his foray into pneumatic weapons. Shame, because his gun looked amazing. He even custom built a road case to store it all. Guy is on the spectrum and has ADHD which has resulted in some amazing, but completely over-engineered, work over the years. He engineered his own gluelam support beams in his garage which could lift a car. He rewired his house using all stranded wire, bus bars and crimp connectors and it was all mil-spec.

ugh123 2y ago

Can parts of these be 3d printed?

mulmen 2y ago
Maybe external mounting brackets? Say for the ignition system or maybe a sight of some kind? I wouldn’t trust a 3D print for any of the high pressure stuff but I don’t actually know if that’s feasible. I’d love to find out I’m wrong.
wepple 2y ago
Not strong enough
annoyingnoob 2y ago
If you like shrapnel.
AngryData 2y ago
Theoretically yes with the right materials, but realistically 3d printing is too sensitive to safely and reliably print pressure vessels of any significant size without putting yourself in danger. Some plastics are going to have weak points between layers that could splint apart instantly and without warning, and other plastics that don't have that problem are often brittle and could throw large chunks. But pressure rated plastic pipe extrusions are fairly cheap (just be aware some are only rated for water pressure, not air pressure). And if you need something small and lightweight, pop bottles can hold up to 100 PSI. Tom Stanton's channel on youtube does a bunch of air powered RC planes and stuff using pop bottles to hold air.

xivzgrev 2y ago

wow this is a fancy one. the one friends & I built in high school was more simple 1) a narrow tube to put potato in 2) a larger tube for firing chamber with a screw cap 3) a sealed hole cut into firing chamber for a lighter put potato in one end, unscrew the cap, spray hairspray liberally inside, screw cap back on, aim, and fire

wepple 2y ago

I built the fauxtato a while back; a small capsule to simulate a potato but with a 32g accelerometer (8g is wildly insufficient) and WiFi to be able to log data and make basic analyses about different cannon & fuel usage. Really interested run some tests based on things in this thread, like different propellants.

wepple 2y ago
Correction: it was a ADXL375 200g sensor
- nehal3m 2y ago
  That is amazing. Can you tell us if the potato referred to in this comment [0] could have done serious damage? [0] https://news.ycombinator.com/item?id=40798939#40812811 https://news.ycombinator.com/item?id=40798939#40812811
  - wepple 2y ago
    That’s really interesting, I haven’t spent much time looking at the data from the landing impact. I’m also not confident in my skills to translate G-forces into velocities or such. I guess it depends largely on what type of surface it lands on? You’ve definitely got me thinking now. There’s a bunch of ways I could roughly come up with a model for this.

deleted 2y ago

[deleted]

flyinghamster 2y ago

A buddy of mine had a compressed-air spud gun that he made from an air compressor tank, a ball valve, and a length of 3" copper pipe. That thing could put dents in a 1/4" thick scrap steel plate.

deleted 2y ago

[deleted]

jprd 2y ago

I have NEVER EVER used one of these to fire across a US Interstate at night (successfully). Mind your PSI and test your ballistics prior to using it for more, artful, purposes.

mejare777 2y ago

[flagged]

rehevkor5 2y ago

Relevant: this video with some info about dangers/safety especially related to non-pressure-rated PVC: https://www.youtube.com/watch?v=KqstP9ics2A https://www.youtube.com/watch?v=KqstP9ics2A

reducesuffering 2y ago

Silicon Valley, the show, is a documentary. https://youtu.be/Q1QPXyebhiY?si=5YWYlCuI2aJ2fu-l&t=474 https://youtu.be/Q1QPXyebhiY?si=5YWYlCuI2aJ2fu-l&t=474

gnarcoregrizz 2y ago

I made few of these when I was a kid. My pièce de résistance was a 10' 'coaxial piston launcher'. It scared the bejeezus out of most people... I usually shot ice slugs, which would throw a hole in a piece of plywood at 50 psi. A golf ball with a chipped off shell fits perfectly in a 2" PVC barrel. The problem with chipping off the shell (along with an unrifled barrel) is that it makes it like a knuckleball - you have no idea where it's going to go. They would curve violently in any direction. One of the few times I shot one of these, it curved directly upwards, and I'm guessing landed a half a mile or so away. Hopefully it didn't hit anyone or anything. That was the last time I shot it.

deleted 2y ago

[deleted]

eigenvalue 2y ago

I used to think these were really cool and harmless fun as a teenager. Then at college, some guys I knew made one (and they weren’t dumb at all, pretty competent people). They were firing it near where people were sitting on the lawn and it suddenly shattered, sending sharp jagged pieces of PVC flying. One of the pieces hit a girl sitting nearby and gave her a nasty cut near her eye. Her face was covered in blood and it was totally horrific for her and everyone else. It made me realize that the fun of the activity was just significantly outweighed by the possible safety downside. It could have been so much worse, too— she could have been blinded instead of just gotten a nasty scar on her face.

spike021 2y ago
I think the key is using them in an open space away from people and where you can have some measure of safety. My friends would use theirs in an uninhabited valley off a ridge.
- eigenvalue 2y ago
  Yes but even then the person firing it is at risk. At a minimum you should use serious eye and face protection.
  - macNchz 2y ago
    When my friends and I made these 20 years ago we leaned into the "cannon" vibe and mounted them on sawhorses held down with sandbags, then the ignition was on a wire so you could step back to fire it. At the time I think it was... not about safety so much as it just seemed cool to do it like that, but I guess that's one way not to actually be holding the thing while it fires.
    - lazide 2y ago
      Notably, cannons also used to sometimes explode randomly when fired.
petee 2y ago

m-i-l 2y ago

Surprised to see people talking about spudguns firing whole potatoes! I didn't even know that was a thing. The spudgun I had when I was young just fired small parts of a potato, with a whole potato enough to last for ages. I think it was the Lone Star Spudmatic. Not only safer but less wasteful. FWIW, it looks like Wikipedia differentiates the smaller spudgun from the larger potato cannon: https://en.wikipedia.org/wiki/Spud_gun https://en.wikipedia.org/wiki/Spud_gun vs https://en.wikipedia.org/wiki/Potato_cannon https://en.wikipedia.org/wiki/Potato_cannon

spjwebster 2y ago
Yours is definitely the spud gun I remember, and I suspect that's true for most folks of a particular age from the UK: a small die cast red gun and a monster potato to feed it ammunition. If we're talking home made back garden arsenal, the go-to for my generation was the peg gun: https://www.instructables.com/A-Great-Peg-Gun/ https://www.instructables.com/A-Great-Peg-Gun/, which is, in retrospect, absolutely irresponsibly lethal with the right tension elastic bands.

ElCapitanMarkla 2y ago

This takes me back. Dad was a plumber so I had ready access to all the gear for this growing up. I was introduced to it when he turned up at home one day with one, we launched a few spuds into the neighbouring paddock using Mum's hairspray. I was about 13 at the time so I spent hours on this site planning different launchers. Managed to blow my friend's Dad's air compressor up while firing a smaller one. I don't know how the hell I still have all my fingers / eyes but I had some fun :)

vlachen 2y ago

In the summer of 2004 I was enjoying the mountainous view and ample sun of Kandahar, Afghanistan. It was there, eating one of my allotted MREs, that I noticed the MRE heater was printed in large letters "Do not expose to flame." Being a bored jarhead, I couldn't help but try and figure out why. Being able to rub a few brain cells together, I thought about how the heaters are activated by the addition of water. Since water is hydrogen and oxygen, I was willing to bet that those were some of the reaction products. I never bothered to look it up, but I did find that whatever was coming out with the steam was also quite flammable. Once that was proven, I recalled that recently a contractor had dug a well near our work site. I ambled over and found a 3 foot long, ~3 inch diameter steel pipe that had a 90 degree elbow with a quick release cap. All that was required after that was a touch hole, added with a drill, some MRE heaters, and projectiles. Potatoes were not available there, but fruit like oranges and pears were. I started with an orange and just jammed it into the very end of the barrel, it was too big to go all the way in, and went for it. The distance was laughable, 1 or 2 feet, but the sound? Everyone came running out of the work center tents because they thought I had just loosed a round from my weapon. After being called an idiot by the local Lieutenant, I switch to only pears, which were easy to jam in hard enough to cut the excess off. At this point, I was lobbing pears across the perimeter road, into the scrub / minefield outside the wire. Never found a mine with it though. All my fun ended one faithful day when I accidentally dropped a pear in front of a Romanian MP truck on patrol around the perimeter. The 50 cal on top turned to point at me, I dropped the pear cannon and walked away, never to return.

bityard 2y ago
> The 50 cal on top turned to point at me, I dropped the pear cannon and walked away Pretty sure I would have dropped something else and RUN away
- vlachen 2y ago
  Kind of like a cat, I didn't want to tickle their predator instinct. If I was on the other side of the wire, it'd probably be a different story. Or no story.
2y ago

gothink 2y ago

I had an amazing science teacher in high school who brought a potato cannon he had built into to class to show us. Except he called it a "sock cannon" and had loaded it with a large tube sock that he had rolled up. He explained how it worked, how he built it from a few basic plumbing parts anyone could get at the hardware store, how the fuel was just hairspray and how we definitely shouldn't build one ourselves. Naturally, I went home and decided to construct a much bigger version of the one he showed us. After convincing my parents to drive me to the hardware store, I picked out what I needed -- including 7 feet of PVC. The clerk immediately figured out what I was building and that was the first time I heard the term potato cannon. They seemed concerned that my mom was on board with the whole thing, but I stuck to my guns and said it was a science project and was for shooting socks. I had figured I could wrap the sock around a smaller projectile, but that clerk made me realize I didn't even need the sock. My friend and I put it all together pretty quickly the next day and set it up in my backyard for testing. I think we probably started with socks, but I honestly can't recall. What I do remember is taking a hacky-sack I had lying around that fit perfectly into the barrel to try and fire it at our back fence. We were using a piezo igniter from a lighter I had disassembled, and it took some trial and error to get the fuel to air mixture just right. It took both of us to operate: one person aimed the barrel, the other operated the trigger. This time, I was aiming and he was lighting. But it just wasn't lighting... so I turned around to try and help and BOOM the cannon went off like, well, a cannon. Except I wasn't pointing at the fence anymore, but well above it. The hacky-sack tore through the branches of several trees before exploding on the metal siding of the house on the opposite side of our block. The sound could probably be heard for blocks. We both just looked at each other with a mixture of delight and panic before immediately running back into my house. We saw someone come out of the house we hit looking utterly confused, trying to figure out what just happened. We started laughing uncontrollably, realizing how close we were to causing a lot of damage, or possibly injuring someone. Luckily, nothing every came of that incident, and we made sure later tests were done in a nearby park. We never did attempt to put an actual potato in the thing. Perhaps 7 feet was a little overkill... PS - Dr. Vince, if you're out there, thank you for being one of the best teachers I've ever had. I'll never forget that class, or that "sock cannon"!

tonetegeatinst 2y ago

Iv been interested in this on and off for a few years. My most sunkworks idea was based of atechnology connections video, to use a stocheometric ratio of liquid hydrogen and liquid oxygen, dump it into a steel pressure chamber....then let the liquids convert into a gas, then detonate the mixed gas using a high voltage arc. The detonation force blows a burst disk open and blasts the projectile slug forward at what I hoped to be hypersonic speeds. Never really got to into it though cuz I'd need some machining equipment and a budget for the materials

fallinditch 2y ago

Adam Savage made something similar, with compressed air, for the Slow Mo Guys - https://youtu.be/w9i9rwg1L_A?feature=shared https://youtu.be/w9i9rwg1L_A?feature=shared

alexpotato 2y ago

My username comes from the fact that I built and sold potato guns back when I was in high school. I should really write up a thread on some of the stories from those days.

hyperdimension 2y ago
Please do! Quirky fun personal websites used to be what the Internet was all about! You have at least one guaranteed reader.

austinkurpuis 2y ago

This website was my dad’s second bible when I was a kid. He went down the rabbit hole and ended up building a massive steel spud gun that had a 10 foot copper barrel. That thing could throw a potato close to a quarter mile. Some great childhood memories right there.

jschveibinz 2y ago

Related vegetable ballistics: Punkin' Chunkin' Championship https://www.punkinchunkin.com/ https://www.punkinchunkin.com/

chasd00 2y ago

I made something like this in HS out of coffee cans with the bottoms cut out in half moon shapes. Then I duct taped them all together and would put rubbing alcohol in the top, shake it up and let it evaporate, and ignite from a nail hole in the bottom can. I could launch Gatorade bottles filled with water about 100 yards. It blew up once and I never bothered to put it back together. Plus my mom was hysterical.

fullspectrumdev 2y ago

Built a bunch of these - both combustion and “compressed air” based as a teenager, with varying results. I had been inspired by a “science demonstration” at a science fair where “Doctor Bunhead” (of “Brainiac” TV fame) shot one through a tennis racquet to make “instant chips”.

demondemidi 2y ago

Back in the late 80s in college a guy in my dorm made a combustion gun. We were watching him shooting spuds from the dorm lawn into the air not caring where it landed. Later that evening he was arrested because one spud gave the parent of a visiting student and orbital fracture 300 yards away and her eyeball literally fell out. Since he was doing it in front of the whole dorm the police had no trouble finding him. He lasted only two weeks in college no idea what happened after he was arrested. Be smart if you make one of these things they are super dangerous.

jsvaughan 2y ago

Good book on this and similar subjects - Backyard Ballistics: Build Potato Cannons, Paper Match Rockets, Cincinnati Fire Kites, Tennis Ball Mortars, and More Dynamite Devices https://www.amazon.com/Backyard-Ballistics-Cannons-Cincinnati-Dynamite/dp/1613740646 https://www.amazon.com/Backyard-Ballistics-Cannons-Cincinnat...

cyrialize 2y ago

A fond memory I had as a teenager was making a potato cannon with my brother and dad. The cannon was in a J shape, where the end of the J had a cap for spraying in fuel - like propane or hairspray. Near the end of the J shape we cut a hole to put in an elongated lighter. This went against the design of the video we watched - the video suggested taking the ignition stuff out of the lighter and making it part of the canon. Cutting a hole and just gluing a lighter was the easiest option... but also caused a lot of problems - namely with ignition. During the building of this, right as my mom came home, I looked down the PVC pipe (there was nothing in it thankfully) and asked my brother to click the lighter so that I could check to see if it was lighting or not. My father was not in the room. This ignited the residual fuel in the pipe and burned ALL of the eyelashes off of my left eye. My father came running in and started to scold us, and then my mom came in the room asking what happened. We all hid everything, because my dad didn't want to get into trouble either. We shot many potatoes that summer, and the whole experience made me realize how useful eyelashes are.

oldgregg 2y ago

ted kaczynski alternate timeline