When I went out to visit Paul Gregg, backyard PVC rollercoaster extraordinaire, he showed me his extensive test results of PVC fracture toughness. He found that PVC lost something like 50% of toughness after a year of daily sunlight (UV exposure causes the plastic to become harder and much more brittle), but painted PVC in the same conditions retained over 98% of the same fracture toughness it started with. Color and type of paint made little difference. From then on I've been painting all my PVC projects.
Building them with my dad as a kid, we always had cut a "duct tape safety" in the rear chamber. If the pressure was too high, it would blow the back off, and remain dangerous directionally (forward and rear) rather than omnidirectionally. He only ever blew the safety when he used acetylene, rather than his usual starter fluid. I never did go back and make a new one when I became an adult, but I wanted to try to build a pneumatic spudgun with an electric solenoid. The pressure can be higher and more consistent, so it's safer than guessing how much starter fluid you used.
What kind of potato gun? Was it compressed air or propane or was it hairspray. Because I imagine a hairspray potato gun would be far safer because pushing a potato out a barrel is far easier than blowing up outwards.
@@BenMyhillJones we usually used starter fluid. Hairspray was ok. Pneumatic would provide a more consistent power, so your safety margins could be higher
My brother’s friend is a steamfitter and he welded a potato cannon out of steel pipe. I believe it was fueled with acetylene and oxygen. It was big and heavy and had its own stand. It launched potatoes out of sight (likely into orbit) with a tremendous bang. Good times.
So, it was the size of a Saturn 5 rocket? The potato cannon? To get into orbit it would have to reach escape velocity. Which is 6 miles a second or roughly 25,000mph.
Second degree burns on my eyelids…I built a potato cannon when I was in high school. Glued all the pieces together and left it over night to cure. The next morning, I hooked up the sparker and looked into the combustion chamber to make sure the leads were close enough to spark. They were. And they ignited all the PVC cement fumes that were still hanging out. The fireball gave me second degree burns on my eye lids. I still have no idea how I was able to close my eyes in time. Careful out there, kids
Yea. I didnt use fire, just air. I didnt use PVC primer with my first. I had it around 100 psi or so when the front barrel blew off. Threw the ~1kg barrel around 10 meters or so in front of me. The air chamber shot backwards and gave my arm a good cut. I still have that scar, and this was 3 or so summers ago I'm hella lucky I didnt get hurt more
I've built half a dozen cannons over the years, always using ABS cellcore, and using butane as the fuel. Never had any of them go catastrophic, even after loading heavy projectiles and abusing the crap outta them. This plastic behaves differently from PVC, particularly when it comes to firing in the wintertime. If you live in a cold climate, never use PVC.
I built a PVC potato cannon many years ago only I used water balloons instead of potatoes. The power, range, and thudding BOOM when I shot the thing were most gratifying. I started off with Aqua-net hairspray but later found that old-school Right Guard deodorant in the brown spray can was much cleaner burning, much more powerful, and left a nice fresh scent! BTW: a cup of paint balls was pretty amazing too. I called it the shotgun of Moses. The paint ball pattern was murder out to 100 feet or so.
I don't think it will break concrete. I did break a wooden privacy fence. It also punched a hole in a plastic dog house one time. I certainly wouldn't shoot it at a person or a pet. Not at a car or a house either. It could easily break a window.@@-jank-willson
if you made one, but used a much smaller diameter pipe, that was too small for potatoes, but just the right size for ball bearings, do you think it would 'end' somebody? AKA a homemade firearm?@@fecklesstech929
I did see a video where somebody broke a concrete slab with a potato launched from one of these. and also put molotovs in it instead of potatoes... @@fecklesstech929
Personally what I would do to secure it is have a loose layer of thick canvas around the cannon and then 2 offset layers of hardware cloth on top of that. I think having something loose around it would be more effective than something tightly hugging it like fiberglass or duct tape because it would give the PVC room to rupture and release the gas inside while still catching the shrapnel.
I would never use any type of PVC at all for any DIY pressure stuff, especially close to you. One of the reasons we use HDPE for fireworks tubes...aside from a decent pressure rating...when it fails, it bulges, stretches, and then shreds.
Dunno; thats kinda what he did and the glass fiber didnt do a very good job of containing the shrapnell. In any case, such a design including the one used here wouldnt improve max pressure; infact the concentrated loads induced by the chicken wire risk substantially weakening the PVC as it gets stretched outward onto the discontinuous metal wire. Pulling a kevlar continuously braided sleeve, or maybe something like UHMWPE (though i dont know thats readily available as sleeve), would provide orders of magnitude more impact toughness than glass, for sure, and if the kevlar is epoxied on, it will provide a crapton of strength and stiffness too, so you can make it so it only blows out the ends and will be safe to hold.
Sensible chuckle: Cutting from a 30k price tag for a suit straight to an ad was one of the best transitions I've seen! Props to the editor/timeline decision maker!
I UNDERSTAND THAT THERE ARE A LOT OF COMMENTS HERE, BUT PLEASE READ IT ! I also try to create interesting content (experiments). Will you write your opinion? dg
The reason there are less hand grenade injuries is entirely due to the fact kids aren't building hand grenades. How many potato guns have you seen in your whole life? Now how many hand grenades?
I was the pressure tester for a company for 2 years. Aluminum tanks with fiberglass and resin covered, used for air/oxygen tanks by Firemen also large tanks for Vans using natural gas also COTA bus natural gas tanks. They almost 6 ft. long and 2.5 ft. diameter. The firemen O2 tanks would blow at 14-20 thousand pounds. They had to fail at the ends also. But of course pop off valves were used when built. Also did fire bomb tests and projectile tests from 30.06. Great job. All was done in a concrete safe and also inside of a metal tube with end caps. The man before me was killed when one blew up wrong, took the safe room door off and hit him. We always crouched down behind the machine on failure tests. D.O.T. was always there watching explosions, recording all findings. All was graphed out on chart paper for reference. Yes we used compressed water thru very thick stainless steel pipe. Each lot of 200 tanks, two were used to test. Testing would used pressure pumps, hydraulics to pump them to 5000 psi over 30 sec. then down to zero over 30 seconds. Then after 10,000 cycles then the pressure went to 7500 psi 30 times, then it went to failure in a concrete reinforced room. Every different size tank had differing pressures. Larger the tank, smaller the pressures.
Pick up your cross and follow Jesus! The world is quickly headed for destruction, and sooner or later you will have to sit at the judgement seat and give an account for your actions. Belief in messiah alone is not enough to grant you salvation - Matthew 7:21-23, John 3:3, John 3:36 (ESV is the best translation for John 3:36). Call on the name of Jesus and pray for Him to intervene in your life! - Revelation 3:20. Contemplate how the Roman Empire fulfilled the role of the beast from the sea in Revelation 13. Revelation 17 confirms that it is in fact Rome. From this we can conclude that A) Jesus is the Son of God and can predict the future or make it happen, B) The world leaders/nations/governments etc have been conspiring together for the last 3000+ years going back to Babylon and before, C) History as we know it is fake. You don't really need to speculate once you start a relationship with God tho. Can't get a response from God? Fasting can help increase your perception and prayer can help initiate events. God will ignore you if your prayer does not align with His purpose (James 4:3) or if you are approaching Him when "unclean" (Isaiah 1:15, Isaiah 59:2, Micah 3:4). Stop eating food sacrificed to idols (McDonald's, Wendy's etc) stop glorifying yourself on social media or making other images of yourself (Second Commandment), stop gossiping about other people, stop watching obscene content etc and you should get a response. Have a blessed day!
Word of advice for next time; you can use argon while it’s on its side. Pressurized gas that’s not liquid can lay sideways and still dispense. Welders do it all the time (I have personally as well). So you could have set the tank next to you behind your barrier for more safety + ease of reading gauges. Great video!
@@recksnfx611 I guess you're right, it just looked like a piece of dark wood to me, but probably it's a rusty sheet. I think it would've been better with legs :D
I just got to say i love that transition into the ad, Showing the suit for 29k, your smug face and then BAM, Ad time! Great work man i love your channel!
When I was a kid my friends dad, who is a mechanical engineer, built us one that we used to set off with hair spray. He used pressure rated pipe and PVC primer and cement and designed it to be fired from about 10 feet away on a stand using long cables with the grill igniter. He also designed it so that if it failed, the end cap would blow off rather than the entire thing exploding. I don’t know how he did it but that’s what he said, and I trust him given the impressive projects he did as an engineer
you could probably friction fit the cap on snugly enough that it is 99.9% less likely to let go than a potato or whatever, using tape or putty or something similarly gap-filling. Look at ... uh, water distillers you can buy online, they're very leaky for the metal (copper) ones, you're supposed to either use PTFE (teflon) tape or "wheat paste" to fill the gaps in the connectors, and that has to both withstand moderate pressure *and* fairly extreme heat (steam under pressure is quite hot)
I UNDERSTAND THAT THERE ARE A LOT OF COMMENTS HERE, BUT PLEASE READ IT ! I also try to create interesting content (experiments). Will you write your opinion? dg
My dad would build ours out of sced 80. We would use hairspray, amd a grill igniter as well. Only we shot them off our shoulders. Obviously looking back it wasn't the safest thing but not the most dangerous either. Never had one blow up luckily
I 'happen to know a kid' back in the day that 100% allegedly made something similar but was like 7ft (2-3ft chamber) and could blast a small pumpkin or multiple potatoes up to 500yds away. normally more in the 200-300 range (even with big hair spray cans 'he' ran into the cost issues a teen has).
When I was in high school my Physics teacher was telling us that when he was in college they had a potato cannon that they would demonstrate for kids are science outreach. One year, their professor decided that "hey shooting flame propelled potatoes at groups of small children is probably a bad idea." And challenged them to come up with a different idea. So some of his buddies had the idea to use liquid nitrogen as a propellant. They would put some liquid nitrogen in a water bottle, drop it down the barrel as a propelling charge with a potato, and let the bottle explode. They, of course, had to test this where there were no people, which is how they were almost arrested for shooting potato canons out on the residence quad green at 3 am.
I have been involved in a failed compressed air fuelled acorn canon incident and it wasn't fun. Couldn't hear anything in one ear for an hour or so and couldn't feel one hand for a couple hours and then all I was feeling was pain for a while. Everything healed alright in the end and I was good. Like he said follow the instructions and test a few times before you go hands on.
The key is to make them out of ABS not PVC. ABS seems to be a bit better at expanding and contracting durring temp change. In Canada, where we have more natural temp changes from summer to winter, all our houses are plumbed with ABS, and not PVC like our southern brothers in America.
When I was a young teenager I wanted to make a potato gun but my parents said no and didn't let me get the materials I needed. Fast forward some time I found some old PVC that had been sitting out in the sun for a couple of years and built a potato gun out of that instead and kept it hidden from my parents. It worked fine for a while but on the last shot it exploded in my hands and even 15 years later I can still hear the ringing in my ears from it.
I had never seen pressure-rated PVC pipe in hardware stores here in the UK, so once, many years ago (like probably 2003 or so) when we were on holiday in Florida, we filled a whole suitcase with assorted fittings and got a couple of 6 foot lengths of pipe back as hold luggage. The guys at the airport didn't know what the hell to make of it 🤣🤣
This is why you should make designated failure points. Something like a plug glued in so if the pressure gets too high it shoots out instead of exploding. The idea is that if it's going to break it'll break in a predictable manner that can planned around and made safe. This is really common in things like water pumps for trains. They have exactly this though the plugs are screwed not glued into place.
I have personally been present in a room when a pvc potato Cannon exploded. My brother had made one using compressed air for the Oklahoma D-Day paintball game and we were testing it a bit. Then he thought it would be funny to put a piece of paper in it and launch it at my other brother's butt in the kitchen without him knowing. So Brother A pressurizes the potato Cannon, keeps it REALLY low pressure so he doesn't risk hurting Brother B, (like 15-20psi tops) and goes to shoulder it. While lifting it up, his shoulder bumped the valve and dumped a little more pressure into it. I saw it happen, I reached up and shut off the valve and tried to stop Brother A before he fired, but he didn't hear me in time, he opened the barrel's valve and the rapid expansion of air made the whole barrel go kablooey. Shrapnel went everywhere, put a hole through a cabinet, took a small chunk out of the countertop, and one piece went clean through an entire roll of paper towels, out the other side and still managed to stick into the plaster wall behind it. It was crazy. By SOME miracle, no one got hurt or injured except Brother A who had a medium sized cut on his hand that had opened the firing valve, but nothing that needed stitches, and some ringing ears. I still remember it all like it was in slow motion. Have never forgotten it. And it's why my kids will not be left home alone unattended for extended periods of time when they're in their teens 😂
This is why I always stayed clear of compressed air cannons. While it seemed you could control the pressure more than using ignitable fuels, it just added another chance for something going wrong to me. I stuck to hairspray, and not clogging the barrel.
I've been making quality potato cannons for years. Only time I've ever had a problem was when I went on vacation and my roommate decided to put a mortar firework into my newest build that had a 3" pipe for the combustion chamber tapered down to a 2" for the barrel. Firework obviously got stuck in the chamber and exploded in his hands. I was very surprised that he was surprised that it shattered on him.
so youre good at making potato cannons, so a specific question. can i make a 29" barrel with a 2" diameter with a 5" long chamber 3" diameter? possibly 4" but taper it? trying to make it resemble an at4 for halloween lol
"I want to test when they explode" - *puts himself into an even more dangerous situation by almost dropping a gas bottle* Seriously though, pressurized gas bottles must ALWAYS stored such that they can not tip to the side, either by securing them with a chain or belt (as shown a few seconds later) or by simply laying them flat on the ground. If they tip and the valve gets sheared off, you've got yourself a missile that will easily make its way through a cinderblock wall.
I saw that happen on a Skyscraper Roof, with a bottle of HVAC Refrigerant. The boys were laying it down on its side when one slipped. The bottle spun in circles for a bit, getting faster and faster, and then launched itself off the roof. And rocketed like the missile it was between Skyscrapers down a Major Municipality's Street. And then went kerplunk in the Bay, about a half-mile away.. It was a good day to burn off some excess luck.
@@TimeSurfer206 One of my teachers always told us the story of how he sat in his garden when suddenly a gas bottle impacted a few meters next to him. Turns out it was from a gas station 2 km away. Tipped on its side and flew off. Edit: Typos
About 50 years ago we used duct tape, steel beer cans and lighter fluid. The building process always seemed to involve alcohol. Probably even more dangerous than using PVC.
I just used metal pipes for the barrel and pressure chamber, and an air compressor. Last one I made when I was 14 could put a pretty good size dent in a car door. I only quit messing with them because I couldn't afford to make the one I wanted. Plus I'm not sure the one I wanted to make would be legal.
My brother works for consumer testing laboratories (UL) and he says everything usually has to test 2 to 3 times over its rated limit. Swing set loads, pipe psi, shoe wear, you name it.
2.5 to 10 times for fluid conveyance. In some rare instances it is only 1.5 but that's usually for very large diameter or ultra high pressure products. 4 times is the norm.
@@thomasbarlow4223 "They are tested to 125 psi and have to remain operational and to 500 psi and must not burst or leak but don't have to work after." -My brother
@@fordmanfinis tell him I said thanks. I am building something and want make sure its safe. 5000psi operation pressure surely must withstand 10k psi but I couldn't see much more than double safety margin. But hey I've been wrong before....
Finally! The other day I was thinking about your channel, I was worried if you had abandoned it. Don't leave us too long. I miss your scientific experiments
@@Heroo01 that's so rude, I'm making a joke and you're flexing your nonreligiousness like it makes you superior. Which is funny because it's really you that lacks common sense. AND I'm not actually religious I'm doing a bit. You really thought "prayer sesh" and praying backyard scientist back was sincere! Do you realize how absurd that is, and that you took it so serious that you felt like you had to insult religious people for it! It's so funny how oblivious you were, I think, I've been drinking bleach and that messes my judgment so maybe I'm the dummy and people take the youtube comments section seriously these days, which would be a good thing, let's clean this cesspool 🌻🌻♥️😊😊😊😊😊
I’ve gotten pretty crazy with potato guns when I was young. From overloading them to using crazy fuel, never had one blow up. Just gotta do a good job cleaning and gluing the pipe.
Glad you enjoyed the quad cannon! It was ridiculously fun to make (even more so to test it), and I truly appreciate the mention. I'll tell ya, though, your MGL style launcher looks absolutely amazing. I need one in my life like now. Can't wait to see the full video!
When it comes to hydrostatic testing, the goal generally isnt to pressurize untill means of failure. To add on to this, you used a pnumatic over hydrolic test which at high pressures (above 135 psig) can quickly become unstable due to a large void forming on the top of the tank. I test hazmat and high pressure tanks as my career, seeing a quick or semi false statement as to say "it diddnt make a difference" just urks me. Even though you would use a hydrostatic pump to correctly test your rig, we use posthole hydrostatic pumps to test NH3 and LPG tanks, it DOES reduce the explosive potential, but its still 400+ psig. Never do this unless you are a trained professional and always wear your PPE Florida man! Haha! Edit: this is just for the grammar nazi. Im not checking my spelling for you 🤙
@@EC-dz4bq if you over pressure them then there is always a possibility. Always keep within the maximum allowable working pressure. There are also factors like material fatigue and tempurature cycling. Look up the data sheet on your tanks and see what or if there is a expiry for wear. If its say 10 years of use then ditch it then and get a new one, but composites are much different than stainless, mild steel and aluminum.
@@shout_2000 I assume the burst disks would prevent that (for the most part?) My pump I use pump it up, also has burst disks. (Mine is not homemade.) Also, all my tanks are made by the rifle manufacturer. They claim to have a lifetime warranty(rifle + tanks), with proper care. So I assume I don't need to change them out? Edit: Not a sponsor, but if the tanks/rifles themselves may help answer. They are Airforce Texans, and Texan SS. Also, I have larger recharging tanks...would those be different?
@@EC-dz4bq not an expert, but I would assume that the lifetime warranty would be trustworthy, as long as you don’t do things like subject the tank(s) to over-pressure, high temperatures, long exposure to sunlight, etc.
Try using Sch 80 PVC.. The grey stuff.. They also make "FRP PVC" used for Seawater RO systems with 1000lb rating.. BTW, my potato gun uses compressed air in a Sch 80 gun..
Wrap the chicken wire LOOSELY a few times around. That way, it will contain the fragments by bending and absorbing their energy. A solid, tight wrap only increases the stiffness, therefore raising the pressure rating - and also the damage it does when it ruptures at those higher pressures it can now whithstand.
I UNDERSTAND THAT THERE ARE A LOT OF COMMENTS HERE, BUT PLEASE READ IT ! I also try to create interesting content (experiments). Will you write your opinion? dg
PVC is transparent to X-rays also if I recall correctly. So the only way to find all the shrapnel in you is through exploratory surgery. Yup, they just gotta dig til they hopefully find it all.
If you ever end up doing fictional content, would LOVE you in a series about a bare budget super villain trying to work your way up... cause your non-fiction content fits that motif perfectly
As an old guy I can tell you that young people like yourselves have a lot on the ball. Experimenting is science, and science is a fantastic thing. We had so much fun with science experiments as a kid. Exciting, yes! Dangerous….sometimes.
I used to sell plastic piping systems. I had a customer (a municipality) have a 16” sch 80 PVC manifold explode with only a 60PSI “bubble” caused by a failed air release valve. While the system was being filled with water after a backwash cycle, the air release valve failed and all the air in the system had nowhere to go. The explosion was heard a mile away and sent shrapnel up to 300 yards away including multiple 100+ lb chunks. One of them totaled a car that it hit. The operator was protected by a concrete wall. But he’s now deaf. There are compressed air plastic piping systems that are specifically designed for that. Either ABS, or polypropylene. Those materials are far more ductile and tear when they fail. PVC fractures because it’s brittle. PVC SHOULD NEVER BE USED FOR COMPRESSED AIR. OR COMPRESSED GAS OF ANY KIND. I DON’T CARE IF ITS “DONE RIGHT” OR NOT. DON’T DO IT!
The 60 psi in a 16" pipe makes me wonder if it was something like that torque vs. horsepower thing in engines. 16" of air would exert more force than 3". So less psi may be needed to burst
Glad to know I'm safe. The canon I built uses 4" pressure rated PVC and a bicycle valve to inflate up to 90PSI held back by a large ball valve. Turn it quick for maximum range. I think the hairspray or other explosive powered ones are more dangerous due to the higher (and uncontrollable) pressures possible.
yes the shockwave pressure spike can be far higher than the expected average gas pressure. Plus shock loading of a material has completely different effects than static loading.
@@fungdark8270 that isn't the issue, its the spike of pressure at the wave colliding with the wall of the tube. And if the spike is too high... well we've seen the results.
4:39 This, IMO, is a great demonstration why mindlessly reinforcing everything might not be the gteatest idea. Sometimes engineers design stuff to have a specific weak points, so in case an item in question fails, it does so in a comtrolled, safer manner. Not exactly the same thing as I tried to describe, but look for example at a rupture valve Holy crap, that pressure... I bet, that could cause not only lacerations, but also ruptured eardrums
Super excited for the next video. In high school, I envisioned a pump-action, cylinder-fed semi-automatic potato cannon. I went so far as to draw up plans and purchased valves and PVC, but never got around to building the thing. Mine was designed around the action also pumping a specific amount of propane and air into the chamber, and in hindsight I seriously doubt it would have worked at all.
For those who are unfamiliar with hydrostatic tests: The cannon exploded because it was still pressurized with a compressible gas. To ensure a safe hydrostatic test the system needs to be pressurized using a water pump. The presence of gas anywhere in the pressurized system can cause a failure to become explosive.
I UNDERSTAND THAT THERE ARE A LOT OF COMMENTS HERE, BUT PLEASE READ IT ! I also try to create interesting content (experiments). Will you write your opinion? dg
@@supremesloth105 He filled the cannon with water, but you can see he is using the same air line used in every other test to pressurize the cannon. The compressed gas in the line (and in the off-camera tank) is what caused the explosion.
I had a potato cannon when I was like eight, and I was showing it to my friends when they were over for a play date. My mom called us up from the treehouse because we had to go, so I want to relieve the pressure in the chamber so I just pulled the valve. Somehow, someway, the CO2 cartridge that was loaded at the time angled itself perfectly and hit my mom square in the forehead.
Me and my best friend in HS made a couple of these back in 01-02. We took them to the local football field during summer break and would sit in either of the end zones and fire potatoes at each other like we were enemy mortar squads. We used hairspray, and eventually swapped to butane because over time whatever additives where in the hairspray would stick to the side of the chamber, would stay lit and we didn't want to melt the sides.
I know i caught this video kinda late but what nobody mentions somehow is that pvc shrapnel is very dangerous for one particular reason if it happens to become embedded in a person its a real pain to remove all of it since it has a similar density as human tissue and does not show up on xrays
True, it is much harder. But the army has come up with some pretty amazing methods for detecting non-metallic shrapnel in the last decade and they are making it to the general public
Hydrotesting or otherwise testing it is of limited value if you don't know what the peak combustion pressure is. I'd love to see someone do a series of tests with combustion of different fuels and fuel air ratios, potato types and weights, and other factors - with a pressure transducer hooked up to an oscilloscope or other fast measurement device
By the first law of thermodynamics, the pressure within a fixed-size container is proportional to number of particles (molecules of gas) times absolute temperature, so the combustion has to either produce lots of gaseous molecules, or heat the gases by a lot to increase pressure. Like to increase pressure by 10 times (say, from 1 atm. to 10 atm.), the number of co2 and h2o molecules produced by the combustion has to be 5x greater than the number of molecules consumed by the combustion and the whole thing has to heat to 2x the room temperature (~590 kelvin or ~600 °F). Solid explosives do both of those, therefore you get a detonation and a fast-moving pressure wave, but hey, if you put that in your potato canon, you already know what to expect. For anything more conventional we can assume your fuel and oxidiser are both gaseous and at normal pressure of 1 atm. (fuels such as gasoline or methanol are still gaseous, because only the vapours actually burn). With conventional fuels you can't really get a detonation unless you use high compression like inside an engine, so the pressure across your entire container will be more or less uniform, no need to worry about peaks and how to measure them. Also with conventional fuels the number of particles produced by the combustion is pretty close to the number of particles consumed for the combustion, so the only factor that actually increases the pressure is the heat. Now to answer your question: as long as you use gaseous fuel and oxidiser and don't pressurise them, the only way the pressure inside a potato canon could ever reach 10 atm. would be if your combustion heated the whole thing to 2950 kelvin (4850°F), and 10 atm. is still way below anything shown in this video. Just don't put explosives or pressurised fuel inside and you're good.
When pressure testing with water you have to make absolutely sure there is no air anywhere in the part or that will be the result, I worked at a water treatment equipment manufacturer for 22 years and we pressure tested tanks about every day and when done properly it makes a loud bang but doesn't send shrapnel flying
Was involved in many pressure tests in construction. Doesn't take much to have a failure. Also have hit a few pieces of PVC pipe when excavating. That stuff grenades uncontrollably. Always cut it with a saw instead of the excavator. I enjoyed others and their potato guns, from a distance that is. I don't trust any explosives 100 percent. Seen the unexpected even in the Army, in a controlled safe environment. Energy/explosives is something to be wary of.
A few years ago, I saw a video of a French youtuber who built a potato canon out of steel that used oxygen and acetylene and with a barrel which had the exact diameter for golf balls. Let's just say it was pretty powerful.
You should probably wear a mask when blasting fiberglass like that. It's not as bad as asbestos, but it still isn't great for your lungs, and this is almost certainly blasts a punch of small fibers all into the air. It's at least not really a carcinogen (that we can tell) but it is still pretty irriating and can cause some asthma/bronchitis like symptoms
I made one many years ago out of copper pipe with an mip on the rear and a threaded pvc cap. The cap was the weak point so any failure would be controlled and directed in a safer direction. It worked really well with aquanet. Also, I sharpened the end of the barrel so it would trim the potato to tight fit as you pushed it in.
@@893R6-w8t 2" barrel 4" combustion chamber. It was 25 years ago, copper was cheaper back then, but I still don't pay anywhere near $30 per foot for 2" type l.
They need to grab an ASME reference for PVC piping and look at the yield/strain curves and yield stresses vs temperature. The calculation for hoop stress is pretty simple too.
WFT are you using for propellant, I shot my spud gun off multiple times in a row. Never got hot, I had also tested it with different length barrels to see how far I could shoot. Best distance was between 500’ and 600’ with a 4” long spud, I used a street female adapter glued into a 3 x 1 1/2 coupling and a male adapter on the barrel. I could split the gun, jam the spud into the male, screw back on, without having to shove the spud down the length of the barrel. A lot easier to load and the male is just slightly smaller than the pipe , so there’s a tiny bit of space for the spud to slide. Also use a tiny amount of WD-40 for barrel lubricant and for propellant, found WD works great and doesn’t get sticky like hairspray.
@@geneticdisorder1900 I always used the cheapest hair spray I could find (White Rain brand usually iirc). it would get pretty hot after a few shots. but not so hot you couldn't touch it or anything. Just can't fire it too fast
7:23 I like your definition of "safe" "Glue everything together properly so that the canon rips itself apart and disintegrates into 1000 pieces rather than blowing off the bottom"
It might not be a bad idea to create a deliberate weak point in the cannon, so you have a reproducible failure pathway. Maybe a shallow cut 1/4" wide by 0.05" deep at the front of the large chamber. Make sure the cut profile is rounded to prevent very low failure pressures due to the creation of stress risers in the plastic. A round file might be a good tool.
Dude- I've seen countless honey ads, but when I saw you could save $1000 on something as obscure as a bomb disposal suit, I finally joined and with your discount.
15 years ago my brother and I had a cannon building contest. He built PVC with a grill igniter and some hairspray. I built mine with 1/8th inch thick, 2 inch diameter steel tube, 1\4 in steel wrapped lower for chamber, that runs on Oxygen and acetylene from my cutting torch. It sounds like a tank cannon, turns potatoes to a fine mist, and puts tennis balls thru 1\2 in plywood. I won......
I have made many potato canons in my youth. I always used the pressure rated pipes. I always duct taped mine for looks, not because I thought it was safer. I always used the cheap, old school hairspray. Always sprayed the minimum, always got a good pop, plenty of power and more than enough thump from the end result. Never had a problem. Problem is the types of fuel a lot of idiots think is a great idea to use as an accelerant. Over complicate it, then yes, prepare for potential consequences of an extremely overpowered, over pressured potato canon. Use a practical fuel, properly glue together, use proper pressure rated pipes and you’ll likely never have an issue. It absolutely comes down to the person constructing it properly
Before PVC, we used empty tin cans, before they punched them from Aluminum. Taped together, built right, they'd send a tennis ball quite a distance on just lighter fluid. I was in the Air Force, couldn't keep it together, but in a box, with a few cut up to make model airplane tanks, the others could be taped together in minutes, fired to wake everyone up, and tear it down in seconds and look just as surprised as anyone.
Just started watching the video but already I want to clarify that the failure PSI rating for PVC varies WILDLY by ambient temp. At colder temps it becomes quite brittle. This is also true for CPVC (the more yellow variant used for drinkable water supply lines), but less so.
My dad and I made a pneumatic tennis ball “cannon” out of schedule 40 PVC when I was a kid. He based it on a design he’d come across while researching where the tank sat under the barrel to shorten the overall length, so it needed two 90° pieces to connect the tank and barrel. One time I thought it would be cool to fill the barrel with water and dump about 100psi. The weight of the water was too much and instead of blowing the water out in a spectacular mist like I’d imagined, it instead just blew the piece between the 90° fittings and the water just drain out the back. The piece that blew out was just inches from my feet and somehow I didn’t get so much as a scratch… afterwards, he tweaked the design by adding two T pieces to increase the area and it still works today, 20 years later
Put it in a kevlar sleeve but don't wrap it tight, it will allow for some expansion and will decelerate the shrapnel since the loose kevlar has time to slow it down
I made the ultimate potato gun. I started with a Gaither Bead Bazooka, an air-powered tool for tire shops to help seat difficult tire beads. It just uses compressed shop air. I unscrewed the diffusing tip and replaced it with a male-threaded copper connector that replaced the diffuser, sweat-soldered to a 14 inch length of 1-1/2 or 2 inch copper pipe. You simply press the open end of the copper pipe into a potato, getting a perfectly-fitting projectile. Charge the Bead Bazooka with compressed air, aim and fire. I get powerful and fairly accurate shots at about a hundred yards. If you want less distance / power, use less air pressure.
Great video! People often ask us if they should build water rockets from PVC, and we always recommend against it for the reasons you show here. I'll be able to point them to this video from now on.
0:10 To be fair, this is what I call the "Dog-Lion Fallacy" or the "Cow-Shark Fallacy". You see, you're more likely to be killed by a Dog than a Lion, yes, but this is not because lions are less dangerous than dogs. It's because we interact with dogs more. Same goes with Potato Cannons.
another good tip is if you have any doubts, make a deliberate failure point. knowing where something is going to fail means you can prepare for that failure much better for instance if you used a hot knife to scratch a weak spot into the pvc, you would KNOW where it was going to fail from, and could point that side away from you, and thereby hopefully be spared the brunt of the failure. that being said, safety first, and if you have any doubts, maybe just dont do it!!!
I used a T fitting and glued the plug in but didn't prime it. After a couple years it blew out so I figured time for a new cannon. It failed while shooting a peach out of it .
Not for this application, because PVC is strain rate sensitive! The material acts differently depending on how fast the strain (due to load or pressure) is applied. Thus the design may be perfectly sound when pressurized with water slowly, as opposed with a gas bottle or air compressor receiver tank which can pressurize the device rapidly. Just a word of caution.
Happened to me, we modded one to accept a propane tank fill, my friend had picked it up for a test shot and walked out from the garage, I looked up and noticed he was filling it a little too much. Just as I began to speak to tell him to not fire, he pressed the igniter, 4" pvc blew into about 1000 pieces, pressure wave hit me pretty good, amazingly my friend didn't get hurt as he was holding it against his body when he pressed the igniter. Got a couple pieces in my mouth as it was open when it happened, but no worse for wear, we laughed it up over beers a little later.
ive made like 10 potato cannons in "not for pressure" pvc pipes and never had an issue. I had a 3 inch rear and a 2 inch barrel and used a bbq spark switch. Anyway, I think properly loading it is a huge variable.
When I was a kid there was still a lot of old metal plumbing/oilfield pipe around. And one of my friends made a monster of a potato cannon out of one. We kept putting more and more dangerous propellant in it. And finally one of us had the bright idea of using propane. The back lid flew off like 20 feet hitting my friend in the ribs breaking 3 of them and cracking his sternum. The Dr said if it was just a inch over it could have killed him. We never shot the potato cannon ever again after that.
@@MrDmadness probably that butane canisters tend to only let out a bit at a time, propane ones you can let out a ton of gas pretty quickly because theyre used for much higher btu applications. At least in my country butane is just for lighters and some small portable stove burners, propane is usually used for heating or soldering or the like where the Gas output is much greater. A small butane canister you push to let gas out may only emit a few ml per second whereas a propane canister with a twist valve for industrial or home heating uses could let out a much larger volume. I know because I have a turbo propane torch for plumbing soldering, it’s 30K btu. My butane torch for cigars is like 1500btu. It’s not about the energy density in this case, it’s the overall volume of gas. Teenagers are not measuring how much they’re putting in a potato cannon in any accurate way, I really doubt anyone would weigh or take the volume of the charge unless they’re like a legitimate engineer. Stop trying to call out fake stories or whatever you were getting at when you aren’t really thinking that detailed about the situation lmao. Mr iamverysmart LOL. yes butane is more energy dense, but it will still make a bigger boom if you accidentally add 5x as much volume of propane than butane since the valve lets far more through at a time than the tiny valves on butane cans that are made to refill lighters.
@@mrjjman2010 no dude, I'm a gasfitter with red seal. Butane burns hotter period. While obviously a greater volume will burn hotter this doesn't change the burn temperature just the size of the gas expansion. The reason your torch works is because it's ported and draws in more air.. its essentially a venturi. Also why not just use Mapp for soldering ? Regardless. Butane has a greater Btu output and a faster trough burn speed. Though you are correct about how the volume is dispensed and since both c4h8 and c4 h10 are more dense than air they can both pool
A Canadian here. I have built a couple of spud guns 15 years ago. We use ABS here. All I learned was on a few webpages and a couple of guys at the lake, mostly on the volume ratio to barrel volume and how to measure propane charges. I never used propane. Under arm deodorant spray was my fuel of choice. Right Guard or Axe. (Axe has about 3 times the amount of solvent and butane in it. So you only use 1/3 as much as Right Guard.) My guns were all breach loaders with threaded connectors and a threaded clean out at the butt end. I had interchangeable barrels, 1.5", 2" and 3" . the different barrels all have different sounds. Smaller crack like a shotgun and the 3" gives a good thump. I have only had one safety issue, a gun fired one day due to static and left a mist of potato in the house when the spud hit the ceiling. In cold weather it was always best to load a warm gun indoors before taking it outside to fire otherwise there is a problem with the mixture. Some of the videos used speed guns to check velocity and one guy had a device to rifle the bore which increased the accuracy significantly into tight groups. He made 2" x48"ABS which I think he sold a few online.
he was just one inciting incident away from becoming a supervillain!! he was a really cool guy, gone way before his time, he is missed... the structure of the cottage is still standing, and I think he'd get a kick out of the fact that we shot a thrash metal music video in it...
Wouldn’t it be safer to purposefully leave it weaker towards the back and make sure to no one stands behind the cannon when firing? Like, use the string PVC pipe strengthened with fiberglass except in the back.
You need an expandable mesh. To catch fragments you slow them down gradually. If you try to contain them at their initial velocity you'll need rigid containment. This is how kevlar body armor works, it's basically a tightly woven fabric (net) with room to move and stretch. Still, pointy bullets will penetrate it so a rigid containment vessel might be wise.
You have to do all the reinforcement but engineer a failure point at the back. If you double up on reinforcement especially with chicken wire, it just becomes more shrapnel. Make a sort of burst point in the back like carving a slight groove in a circle in the back
3:38 When the pressure at the cylinder is 200 it will not be 200 at the pvc pipe under the dynamic conditions of your experiment . The gas is travelling along a very small bore long tube . You have to increase pressure VERY slowly for reading to have any meaning.
This man gets it. For the electric crowd, the PVC pipe is like a capacitor being filled through a resistor from a voltage source - we would have to calculate the air mass (charge) that had already flowed into or is currently flowing into it to infer the pressure.
I made a "blow gun" out of a medium sized fire extinguisher to shoot marbles at stray dogs and raccoons. It recharges from an ordinary compressor to 195 psi through a short air valve screwed into the tank, secured by a nut on the inside. I use a lever valve to "fire" it. I've used it with homemade "spears" made of PVC and sharpened spikes as well. They fit over the smaller PVC tube that I use to shoot the marbles with and I gave them fins to help stabilize their flight. Not long ranged but fun with a backyard target.
Literally built one a week ago and the end cap exploded into my hand! My fingers are still struggling to bend and hurt alot! If only this video was posted 7 days earlier...
For a few years now I don't glue on the end cap properly on purpose so that in the case of to much pressure buildup there is a place that gives and the pipe doesn't explode in my hip or cheek. It's scary how often people build something without any predetermined breaking point, safety valve or whatever is suitable for the built...
That's not too bad an idea, but a pressure relief valve or burst disc is a better one. They are considerably safer and will act at a known pressure. They can be had on Amazon for under $10.
I recently made my third (and largest at 6'4" long) Potato cannon. I've thus far made all of them combustion style out of black schedule 40 ABS. The only issue I've had as far as explosion goes was due to an ignition system mounting bolt that I (very stupidly) mounted through the blast chamber wall. However, instead of completely shattering or sending shrapnel everywhere, it cracked about halfway around the chamber in an arc shape and singed some arm hairs in the process. I was recently trying to figure out pressure levels created by one of these cannons and would be interested to see you explore this a bit as well. I have a few videos of my current and past cannon models on my own youtube channel for reference.
Now I think about that, using a weak end cap seal or other part could be a safety device for overpressures as a controlled release. Like the M1 Abrams blowout panels.
When I went out to visit Paul Gregg, backyard PVC rollercoaster extraordinaire, he showed me his extensive test results of PVC fracture toughness. He found that PVC lost something like 50% of toughness after a year of daily sunlight (UV exposure causes the plastic to become harder and much more brittle), but painted PVC in the same conditions retained over 98% of the same fracture toughness it started with. Color and type of paint made little difference. From then on I've been painting all my PVC projects.
Well, that makes sense. I'm gonna paint my outdoor pipes.
So it's suntan lotion for PVC lol
Cooll
Can't wait for your next upload
What type of paint? UV resistent acrylic paint?
Make videos bro
Babe wake up the backyard scientist just posted
@Don't Read My Profile Photo L
@Don't Read My Profile Photo ok
And he has POTATO CANNONS!
Let's gooooooo!!!!!!
@Don't Read My Profile Photo ok
Building them with my dad as a kid, we always had cut a "duct tape safety" in the rear chamber. If the pressure was too high, it would blow the back off, and remain dangerous directionally (forward and rear) rather than omnidirectionally. He only ever blew the safety when he used acetylene, rather than his usual starter fluid.
I never did go back and make a new one when I became an adult, but I wanted to try to build a pneumatic spudgun with an electric solenoid. The pressure can be higher and more consistent, so it's safer than guessing how much starter fluid you used.
What kind of potato gun? Was it compressed air or propane or was it hairspray. Because I imagine a hairspray potato gun would be far safer because pushing a potato out a barrel is far easier than blowing up outwards.
@@BenMyhillJones we usually used starter fluid. Hairspray was ok.
Pneumatic would provide a more consistent power, so your safety margins could be higher
@Don't Read My Profile Photo ok
Did you say acetylene?!
We would wrap ours in bailing wire and/or fiberglass. Never had an RUD.
My brother’s friend is a steamfitter and he welded a potato cannon out of steel pipe. I believe it was fueled with acetylene and oxygen. It was big and heavy and had its own stand. It launched potatoes out of sight (likely into orbit) with a tremendous bang. Good times.
I'd love to have one of those.
I love this!
Classic combo of gasses, great for old fashioned welding
Bring out the tater 8 pounder! tally ho lads!
So, it was the size of a Saturn 5 rocket? The potato cannon?
To get into orbit it would have to reach escape velocity. Which is 6 miles a second or roughly 25,000mph.
Second degree burns on my eyelids…I built a potato cannon when I was in high school. Glued all the pieces together and left it over night to cure. The next morning, I hooked up the sparker and looked into the combustion chamber to make sure the leads were close enough to spark. They were. And they ignited all the PVC cement fumes that were still hanging out. The fireball gave me second degree burns on my eye lids. I still have no idea how I was able to close my eyes in time. Careful out there, kids
Thankfully, the blinking reflex is the fastes reflex we have. Eyes are precious.
Yea. I didnt use fire, just air.
I didnt use PVC primer with my first. I had it around 100 psi or so when the front barrel blew off. Threw the ~1kg barrel around 10 meters or so in front of me. The air chamber shot backwards and gave my arm a good cut. I still have that scar, and this was 3 or so summers ago
I'm hella lucky I didnt get hurt more
Thank god you can still see
I did the exact same thing when I built my first one
@@bagelsgarage seriously? Haha glue fumes are the hidden killer
I've built half a dozen cannons over the years, always using ABS cellcore, and using butane as the fuel. Never had any of them go catastrophic, even after loading heavy projectiles and abusing the crap outta them. This plastic behaves differently from PVC, particularly when it comes to firing in the wintertime. If you live in a cold climate, never use PVC.
My ABS cannon is 18+ years old.
We used to use hairspray on the cannons we built in high school in the 90s
@@djhaloeight I didn't like hairspray as it gummed everything up. I had good success with a generic Dollar Store version of Right Guard deodorant.
Yeah, I have multiple 10 plus year old cannons. Never used PVC. I use aqua net hair spray and some heavy and tight fiting objects. Never had a failure
@@minter_fab_mafia Walnuts right off the tree with their husks still on will kill a deer. At least that's what I hear.
I'm sorry, did this man take a Bong hit through a potato cannon? Legend
I laughed for a good 10 minutes at that
I just started the video and haven't gotten past this spot. I was like omg. I came here for this comment.
@@lucivarsadiablo4191 happy to provide
I thought I was going crazy does he usually do stuff like that lol
lol that was funny
I built a PVC potato cannon many years ago only I used water balloons instead of potatoes. The power, range, and thudding BOOM when I shot the thing were most gratifying. I started off with Aqua-net hairspray but later found that old-school Right Guard deodorant in the brown spray can was much cleaner burning, much more powerful, and left a nice fresh scent! BTW: a cup of paint balls was pretty amazing too. I called it the shotgun of Moses. The paint ball pattern was murder out to 100 feet or so.
you used deoderant as fuel?? was it powerful enough to break concret (or bones?)
I don't think it will break concrete. I did break a wooden privacy fence. It also punched a hole in a plastic dog house one time. I certainly wouldn't shoot it at a person or a pet. Not at a car or a house either. It could easily break a window.@@-jank-willson
if you made one, but used a much smaller diameter pipe, that was too small for potatoes, but just the right size for ball bearings, do you think it would 'end' somebody? AKA a homemade firearm?@@fecklesstech929
I did see a video where somebody broke a concrete slab with a potato launched from one of these. and also put molotovs in it instead of potatoes...
@@fecklesstech929
Love how the blast shield is basically just a -sheet of plywood- small metal plate they have to crouch behind. Love it.
That's not plywood it's a metal plate.
@@FearThePegasus *inflates you, making you big and round*
how did you cross that out??
@@johnyray6801 ˙ɔıƃɐɯ
@@ChrisD__ *detaches argon hose* Not today bud
Personally what I would do to secure it is have a loose layer of thick canvas around the cannon and then 2 offset layers of hardware cloth on top of that. I think having something loose around it would be more effective than something tightly hugging it like fiberglass or duct tape because it would give the PVC room to rupture and release the gas inside while still catching the shrapnel.
This is what they do with cevlar jackets around drive shafts /gear boxes at racing
I would never use any type of PVC at all for any DIY pressure stuff, especially close to you. One of the reasons we use HDPE for fireworks tubes...aside from a decent pressure rating...when it fails, it bulges, stretches, and then shreds.
Dunno; thats kinda what he did and the glass fiber didnt do a very good job of containing the shrapnell. In any case, such a design including the one used here wouldnt improve max pressure; infact the concentrated loads induced by the chicken wire risk substantially weakening the PVC as it gets stretched outward onto the discontinuous metal wire. Pulling a kevlar continuously braided sleeve, or maybe something like UHMWPE (though i dont know thats readily available as sleeve), would provide orders of magnitude more impact toughness than glass, for sure, and if the kevlar is epoxied on, it will provide a crapton of strength and stiffness too, so you can make it so it only blows out the ends and will be safe to hold.
Works good for hydraulic hoses with tiny wire shrapnel. It's usually nylon webbing.
Just go with a larger PVC pipe outside the one you're pressurizing...
Sensible chuckle: Cutting from a 30k price tag for a suit straight to an ad was one of the best transitions I've seen! Props to the editor/timeline decision maker!
I UNDERSTAND THAT THERE ARE A LOT OF COMMENTS HERE, BUT PLEASE READ IT !
I also try to create interesting content (experiments). Will you write your opinion? dg
The reason there are less hand grenade injuries is entirely due to the fact kids aren't building hand grenades. How many potato guns have you seen in your whole life? Now how many hand grenades?
the way how he looked at the price of a bombsuit (30k) then looked at the camera before it cut to a sponsor is hilarious.
I was about to say that as well, but hey, you could probably label it as a business expense right?
Made me laugh ngl
Too funny
now that's how you transition to an ad
too bad Honey is kinda a scam.
I was the pressure tester for a company for 2 years. Aluminum tanks with fiberglass and resin covered, used for air/oxygen tanks by Firemen also large tanks for Vans using natural gas also COTA bus natural gas tanks. They almost 6 ft. long and 2.5 ft. diameter. The firemen O2 tanks would blow at 14-20 thousand pounds. They had to fail at the ends also. But of course pop off valves were used when built. Also did fire bomb tests and projectile tests from 30.06. Great job. All was done in a concrete safe and also inside of a metal tube with end caps. The man before me was killed when one blew up wrong, took the safe room door off and hit him. We always crouched down behind the machine on failure tests. D.O.T. was always there watching explosions, recording all findings. All was graphed out on chart paper for reference. Yes we used compressed water thru very thick stainless steel pipe. Each lot of 200 tanks, two were used to test. Testing would used pressure pumps, hydraulics to pump them to 5000 psi over 30 sec. then down to zero over 30 seconds. Then after 10,000 cycles then the pressure went to 7500 psi 30 times, then it went to failure in a concrete reinforced room. Every different size tank had differing pressures. Larger the tank, smaller the pressures.
Ever have any close calls yourself?
Yeah... should I be worried about putting 4500psi carbon fiber tanks on my face while shooting my rifle? (Also have a 3000psi aluminum)
4th of July every work day want more could you ask for? Bring you Kid to work day. Where do you work now?
Pick up your cross and follow Jesus! The world is quickly headed for destruction, and sooner or later you will have to sit at the judgement seat and give an account for your actions. Belief in messiah alone is not enough to grant you salvation - Matthew 7:21-23, John 3:3, John 3:36 (ESV is the best translation for John 3:36). Call on the name of Jesus and pray for Him to intervene in your life! - Revelation 3:20.
Contemplate how the Roman Empire fulfilled the role of the beast from the sea in Revelation 13. Revelation 17 confirms that it is in fact Rome. From this we can conclude that A) Jesus is the Son of God and can predict the future or make it happen, B) The world leaders/nations/governments etc have been conspiring together for the last 3000+ years going back to Babylon and before, C) History as we know it is fake. You don't really need to speculate once you start a relationship with God tho.
Can't get a response from God? Fasting can help increase your perception and prayer can help initiate events. God will ignore you if your prayer does not align with His purpose (James 4:3) or if you are approaching Him when "unclean" (Isaiah 1:15, Isaiah 59:2, Micah 3:4). Stop eating food sacrificed to idols (McDonald's, Wendy's etc) stop glorifying yourself on social media or making other images of yourself (Second Commandment), stop gossiping about other people, stop watching obscene content etc and you should get a response. Have a blessed day!
Compressed water? I thought water was incompressable
Word of advice for next time; you can use argon while it’s on its side. Pressurized gas that’s not liquid can lay sideways and still dispense. Welders do it all the time (I have personally as well). So you could have set the tank next to you behind your barrier for more safety + ease of reading gauges. Great video!
I would also suggest a thicker plate of cardboard for protection. Like, at least two layers :D
Plus it won't fall over sideways and hit you in the head while you're hiding behind it...
@@TheWinjin That was sheet metal
@@recksnfx611 I guess you're right, it just looked like a piece of dark wood to me, but probably it's a rusty sheet. I think it would've been better with legs :D
I just got to say i love that transition into the ad, Showing the suit for 29k, your smug face and then BAM, Ad time! Great work man i love your channel!
When I was a kid my friends dad, who is a mechanical engineer, built us one that we used to set off with hair spray. He used pressure rated pipe and PVC primer and cement and designed it to be fired from about 10 feet away on a stand using long cables with the grill igniter. He also designed it so that if it failed, the end cap would blow off rather than the entire thing exploding. I don’t know how he did it but that’s what he said, and I trust him given the impressive projects he did as an engineer
you could probably friction fit the cap on snugly enough that it is 99.9% less likely to let go than a potato or whatever, using tape or putty or something similarly gap-filling. Look at ... uh, water distillers you can buy online, they're very leaky for the metal (copper) ones, you're supposed to either use PTFE (teflon) tape or "wheat paste" to fill the gaps in the connectors, and that has to both withstand moderate pressure *and* fairly extreme heat (steam under pressure is quite hot)
I UNDERSTAND THAT THERE ARE A LOT OF COMMENTS HERE, BUT PLEASE READ IT !
I also try to create interesting content (experiments). Will you write your opinion? dg
You just need to make sure the threads on the end cap will shear off well before the pressure gets to dangerous levels.
My dad would build ours out of sced 80. We would use hairspray, amd a grill igniter as well. Only we shot them off our shoulders. Obviously looking back it wasn't the safest thing but not the most dangerous either. Never had one blow up luckily
I 'happen to know a kid' back in the day that 100% allegedly made something similar but was like 7ft (2-3ft chamber) and could blast a small pumpkin or multiple potatoes up to 500yds away. normally more in the 200-300 range (even with big hair spray cans 'he' ran into the cost issues a teen has).
When I was in high school my Physics teacher was telling us that when he was in college they had a potato cannon that they would demonstrate for kids are science outreach. One year, their professor decided that "hey shooting flame propelled potatoes at groups of small children is probably a bad idea." And challenged them to come up with a different idea. So some of his buddies had the idea to use liquid nitrogen as a propellant. They would put some liquid nitrogen in a water bottle, drop it down the barrel as a propelling charge with a potato, and let the bottle explode. They, of course, had to test this where there were no people, which is how they were almost arrested for shooting potato canons out on the residence quad green at 3 am.
Done this with dry ice, tons of fun! Until one doesn't go off...
I agree with Adam, the scariest explosive is the one that doesn't actually explode XD
*after a few drinks and some engineering.
@@Lizlodude A BB gun will take care of the ones that don't go off. ;)
@@8180634 better be a fricken pellet gun and not something you'd give a 10 year old
@@TheHippyProductions when they are almost ready to pop, it doesn't take much to finish the job.
I have been involved in a failed compressed air fuelled acorn canon incident and it wasn't fun. Couldn't hear anything in one ear for an hour or so and couldn't feel one hand for a couple hours and then all I was feeling was pain for a while. Everything healed alright in the end and I was good. Like he said follow the instructions and test a few times before you go hands on.
Good thing you healed up, ear damage is no fun.
Any damage isnt really but ear damage can be a menace for a while
As a "retired" long time club DJ: hear loss and ear drum rupture isn't as much fun as you might think...
@@Seelenschmiede Huh, guess I should cross that off my bucket list?
@@Seelenschmiede It was awful, felt like one of those war movies after the shell hits next to the protagonist.
The key is to make them out of ABS not PVC.
ABS seems to be a bit better at expanding and contracting durring temp change.
In Canada, where we have more natural temp changes from summer to winter, all our houses are plumbed with ABS, and not PVC like our southern brothers in America.
When I was a young teenager I wanted to make a potato gun but my parents said no and didn't let me get the materials I needed. Fast forward some time I found some old PVC that had been sitting out in the sun for a couple of years and built a potato gun out of that instead and kept it hidden from my parents. It worked fine for a while but on the last shot it exploded in my hands and even 15 years later I can still hear the ringing in my ears from it.
Ik heb 2 aardappelkanonnen, en er is er één nog maar een paar keer ontploft! Veilig zat!😌
@@superkip5920 net 'n paar keer...
@@Sundownnnn lol
Waarom praten we ineens Nederlands?
@@BigBodyBiggolo omdat Nederlands de beste taal ter wereld is!😀
I had never seen pressure-rated PVC pipe in hardware stores here in the UK, so once, many years ago (like probably 2003 or so) when we were on holiday in Florida, we filled a whole suitcase with assorted fittings and got a couple of 6 foot lengths of pipe back as hold luggage. The guys at the airport didn't know what the hell to make of it 🤣🤣
Damn plumbing enthusiasts with their product samples.
Wow that is a genuinely amusing story lmao
I imagine the TSA dude's just thinking "none of this is actually against the rules, but I really don't want it on the plane..."
Sorry sir but we are going to confiscate your Spud Gun parts. They have no serial numbers on them.
Same in ireland
highly recommend making the bottom part the weakspot.
its way safer having it just blow out the bottom instead of acting like a frag grenade
Exactly this - fail safe should be the design goal.
who cares about safety?
@@squidwardo7074 Is that you, Cyrus?
ua-cam.com/video/47Yxa9IeJEc/v-deo.html
How about making the combustion chamber out of metal tubing where welding and fasteners are used instead of glue?
@@iceho6460 that sir is a pipe bomb
This is why you should make designated failure points. Something like a plug glued in so if the pressure gets too high it shoots out instead of exploding. The idea is that if it's going to break it'll break in a predictable manner that can planned around and made safe.
This is really common in things like water pumps for trains. They have exactly this though the plugs are screwed not glued into place.
I have personally been present in a room when a pvc potato Cannon exploded. My brother had made one using compressed air for the Oklahoma D-Day paintball game and we were testing it a bit. Then he thought it would be funny to put a piece of paper in it and launch it at my other brother's butt in the kitchen without him knowing.
So Brother A pressurizes the potato Cannon, keeps it REALLY low pressure so he doesn't risk hurting Brother B, (like 15-20psi tops) and goes to shoulder it. While lifting it up, his shoulder bumped the valve and dumped a little more pressure into it. I saw it happen, I reached up and shut off the valve and tried to stop Brother A before he fired, but he didn't hear me in time, he opened the barrel's valve and the rapid expansion of air made the whole barrel go kablooey. Shrapnel went everywhere, put a hole through a cabinet, took a small chunk out of the countertop, and one piece went clean through an entire roll of paper towels, out the other side and still managed to stick into the plaster wall behind it. It was crazy.
By SOME miracle, no one got hurt or injured except Brother A who had a medium sized cut on his hand that had opened the firing valve, but nothing that needed stitches, and some ringing ears.
I still remember it all like it was in slow motion. Have never forgotten it. And it's why my kids will not be left home alone unattended for extended periods of time when they're in their teens 😂
This is why I always stayed clear of compressed air cannons. While it seemed you could control the pressure more than using ignitable fuels, it just added another chance for something going wrong to me. I stuck to hairspray, and not clogging the barrel.
One boy has half a brain when you put two boys together, they have a quarter brain when you put three boys together, they have no brain
I've been making quality potato cannons for years. Only time I've ever had a problem was when I went on vacation and my roommate decided to put a mortar firework into my newest build that had a 3" pipe for the combustion chamber tapered down to a 2" for the barrel. Firework obviously got stuck in the chamber and exploded in his hands.
I was very surprised that he was surprised that it shattered on him.
make way, mr brain is coming in
How do you make a potato cannon? Or what defines a potato cannon and what are some do's and don'ts when trying to make one, sorry if I'm asking much
He stoopeed
so youre good at making potato cannons, so a specific question. can i make a 29" barrel with a 2" diameter with a 5" long chamber 3" diameter? possibly 4" but taper it? trying to make it resemble an at4 for halloween lol
Does your roommate just randomly play with your things, trying on your used condoms???
"I want to test when they explode" - *puts himself into an even more dangerous situation by almost dropping a gas bottle*
Seriously though, pressurized gas bottles must ALWAYS stored such that they can not tip to the side, either by securing them with a chain or belt (as shown a few seconds later) or by simply laying them flat on the ground. If they tip and the valve gets sheared off, you've got yourself a missile that will easily make its way through a cinderblock wall.
I saw that happen on a Skyscraper Roof, with a bottle of HVAC Refrigerant. The boys were laying it down on its side when one slipped. The bottle spun in circles for a bit, getting faster and faster, and then launched itself off the roof. And rocketed like the missile it was between Skyscrapers down a Major Municipality's Street. And then went kerplunk in the Bay, about a half-mile away..
It was a good day to burn off some excess luck.
"A cinder block wall"????
More like a dozen cinder block walls.
@@TimeSurfer206 One of my teachers always told us the story of how he sat in his garden when suddenly a gas bottle impacted a few meters next to him. Turns out it was from a gas station 2 km away. Tipped on its side and flew off.
Edit: Typos
@@whynotjustmyusername I am not at all surprised or skeptical. I grew up IN a Welding Shop: My Grandpa's.
the cap was on
About 50 years ago we used duct tape, steel beer cans and lighter fluid. The building process always seemed to involve alcohol. Probably even more dangerous than using PVC.
I just used metal pipes for the barrel and pressure chamber, and an air compressor. Last one I made when I was 14 could put a pretty good size dent in a car door. I only quit messing with them because I couldn't afford to make the one I wanted. Plus I'm not sure the one I wanted to make would be legal.
"lock a kid in a room with a potato cannon and a live hand grenade"
Wise words to live by
imagine a soldier launching unpinned grenades from a potato canon.
the grenade would strike open as it leaves the barrel.
hahahahha
My brother works for consumer testing laboratories (UL) and he says everything usually has to test 2 to 3 times over its rated limit. Swing set loads, pipe psi, shoe wear, you name it.
2.5 to 10 times for fluid conveyance. In some rare instances it is only 1.5 but that's usually for very large diameter or ultra high pressure products. 4 times is the norm.
Hey ask him about water valves. What is their safety rating
@@thomasbarlow4223 "They are tested to 125 psi and have to remain operational and to 500 psi and must not burst or leak but don't have to work after." -My brother
PVC pressure pipe is generally designed to withstand 3.2x the rated pressure in short term rupture tests. Check out ASTM D2241 or AWWA C900.
@@fordmanfinis tell him I said thanks. I am building something and want make sure its safe. 5000psi operation pressure surely must withstand 10k psi but I couldn't see much more than double safety margin. But hey I've been wrong before....
Finally! The other day I was thinking about your channel, I was worried if you had abandoned it. Don't leave us too long. I miss your scientific experiments
I thought the same thing and you must have also done a prayer sesh the same time I did cuz we brought him back
@@corncobjohnsonreal LMFAO like praying is gonna make him upload a new video
How come religious folk lack common sense
@@Heroo01 I FELT THE VIBES
@@Heroo01 that's so rude, I'm making a joke and you're flexing your nonreligiousness like it makes you superior. Which is funny because it's really you that lacks common sense. AND I'm not actually religious I'm doing a bit. You really thought "prayer sesh" and praying backyard scientist back was sincere! Do you realize how absurd that is, and that you took it so serious that you felt like you had to insult religious people for it! It's so funny how oblivious you were, I think, I've been drinking bleach and that messes my judgment so maybe I'm the dummy and people take the youtube comments section seriously these days, which would be a good thing, let's clean this cesspool 🌻🌻♥️😊😊😊😊😊
If one day Backyard Scientist stops uploading, I don't think it'll be because he abandoned it
I’ve gotten pretty crazy with potato guns when I was young. From overloading them to using crazy fuel, never had one blow up. Just gotta do a good job cleaning and gluing the pipe.
Glad you enjoyed the quad cannon! It was ridiculously fun to make (even more so to test it), and I truly appreciate the mention. I'll tell ya, though, your MGL style launcher looks absolutely amazing. I need one in my life like now. Can't wait to see the full video!
That was a badass creation man 😎
It's mgs for metal gear solid
Seem like you really like that bomb suit. Maybe you can make one and then try and see how effective it is for a future episode?
When it comes to hydrostatic testing, the goal generally isnt to pressurize untill means of failure. To add on to this, you used a pnumatic over hydrolic test which at high pressures (above 135 psig) can quickly become unstable due to a large void forming on the top of the tank.
I test hazmat and high pressure tanks as my career, seeing a quick or semi false statement as to say "it diddnt make a difference" just urks me. Even though you would use a hydrostatic pump to correctly test your rig, we use posthole hydrostatic pumps to test NH3 and LPG tanks, it DOES reduce the explosive potential, but its still 400+ psig.
Never do this unless you are a trained professional and always wear your PPE Florida man! Haha!
Edit: this is just for the grammar nazi. Im not checking my spelling for you 🤙
Yeah... can that happen to my 3000psi and 4500 psi carbon fiber and aluminum tanks for my rifle?
@@EC-dz4bq if you over pressure them then there is always a possibility. Always keep within the maximum allowable working pressure. There are also factors like material fatigue and tempurature cycling. Look up the data sheet on your tanks and see what or if there is a expiry for wear. If its say 10 years of use then ditch it then and get a new one, but composites are much different than stainless, mild steel and aluminum.
@@shout_2000 I assume the burst disks would prevent that (for the most part?) My pump I use pump it up, also has burst disks. (Mine is not homemade.)
Also, all my tanks are made by the rifle manufacturer. They claim to have a lifetime warranty(rifle + tanks), with proper care. So I assume I don't need to change them out?
Edit: Not a sponsor, but if the tanks/rifles themselves may help answer. They are Airforce Texans, and Texan SS. Also, I have larger recharging tanks...would those be different?
@@EC-dz4bq not an expert, but I would assume that the lifetime warranty would be trustworthy, as long as you don’t do things like subject the tank(s) to over-pressure, high temperatures, long exposure to sunlight, etc.
@@gruntopolouski5919 Thank you
Try using Sch 80 PVC.. The grey stuff.. They also make "FRP PVC" used for Seawater RO systems with 1000lb rating.. BTW, my potato gun uses compressed air in a Sch 80 gun..
HEY,.. SHUT UP 😳
These guys are Experts.
And have No Idea what Schedule Piping Is 😂👍🤤
Wrap the chicken wire LOOSELY a few times around. That way, it will contain the fragments by bending and absorbing their energy. A solid, tight wrap only increases the stiffness, therefore raising the pressure rating - and also the damage it does when it ruptures at those higher pressures it can now whithstand.
I UNDERSTAND THAT THERE ARE A LOT OF COMMENTS HERE, BUT PLEASE READ IT !
I also try to create interesting content (experiments). Will you write your opinion? dg
I prefer using Kevlar condoms and duct tape. You’ll never have to worry about it blowing a load right next to your face .😂
PVC is transparent to X-rays also if I recall correctly. So the only way to find all the shrapnel in you is through exploratory surgery. Yup, they just gotta dig til they hopefully find it all.
If you ever end up doing fictional content, would LOVE you in a series about a bare budget super villain trying to work your way up... cause your non-fiction content fits that motif perfectly
Might have to give them names like "Potato Launch-inator" 😁
Oh no, Potatoelaunchinator has striken again with his Potatoelauncher 3.000!"
As an old guy I can tell you that young people like yourselves have a lot on the ball. Experimenting is science, and science is a fantastic thing. We had so much fun with science experiments as a kid. Exciting, yes! Dangerous….sometimes.
I used to sell plastic piping systems. I had a customer (a municipality) have a 16” sch 80 PVC manifold explode with only a 60PSI “bubble” caused by a failed air release valve. While the system was being filled with water after a backwash cycle, the air release valve failed and all the air in the system had nowhere to go. The explosion was heard a mile away and sent shrapnel up to 300 yards away including multiple 100+ lb chunks. One of them totaled a car that it hit. The operator was protected by a concrete wall. But he’s now deaf. There are compressed air plastic piping systems that are specifically designed for that. Either ABS, or polypropylene. Those materials are far more ductile and tear when they fail. PVC fractures because it’s brittle. PVC SHOULD NEVER BE USED FOR COMPRESSED AIR. OR COMPRESSED GAS OF ANY KIND. I DON’T CARE IF ITS “DONE RIGHT” OR NOT. DON’T DO IT!
Are you family of Juan ?
Now I want to make something that can be heard a mile away too!
The 60 psi in a 16" pipe makes me wonder if it was something like that torque vs. horsepower thing in engines. 16" of air would exert more force than 3". So less psi may be needed to burst
I am wondering if this might draw a "Destructive Device" visit from the BATFE... wouldn't be the first time youtubers have been visited.
I'd want to see a link to the news story on this before I believe it. Schedule 80 failing at just 60 psi?
Glad to know I'm safe. The canon I built uses 4" pressure rated PVC and a bicycle valve to inflate up to 90PSI held back by a large ball valve. Turn it quick for maximum range. I think the hairspray or other explosive powered ones are more dangerous due to the higher (and uncontrollable) pressures possible.
yes the shockwave pressure spike can be far higher than the expected average gas pressure. Plus shock loading of a material has completely different effects than static loading.
@@avroarchitect1793 haven’t people found out the perfect dimensions for the pressure wave to hit the projectile or something?
@@fungdark8270 that isn't the issue, its the spike of pressure at the wave colliding with the wall of the tube. And if the spike is too high... well we've seen the results.
The way he looked at the camera is like: "I'd preferably die" 5:48
4:39
This, IMO, is a great demonstration why mindlessly reinforcing everything might not be the gteatest idea. Sometimes engineers design stuff to have a specific weak points, so in case an item in question fails, it does so in a comtrolled, safer manner. Not exactly the same thing as I tried to describe, but look for example at a rupture valve
Holy crap, that pressure... I bet, that could cause not only lacerations, but also ruptured eardrums
Super excited for the next video. In high school, I envisioned a pump-action, cylinder-fed semi-automatic potato cannon. I went so far as to draw up plans and purchased valves and PVC, but never got around to building the thing. Mine was designed around the action also pumping a specific amount of propane and air into the chamber, and in hindsight I seriously doubt it would have worked at all.
It may work
For those who are unfamiliar with hydrostatic tests: The cannon exploded because it was still pressurized with a compressible gas. To ensure a safe hydrostatic test the system needs to be pressurized using a water pump. The presence of gas anywhere in the pressurized system can cause a failure to become explosive.
I UNDERSTAND THAT THERE ARE A LOT OF COMMENTS HERE, BUT PLEASE READ IT !
I also try to create interesting content (experiments). Will you write your opinion? dg
He tried that in the video
@@supremesloth105 He filled the cannon with water, but you can see he is using the same air line used in every other test to pressurize the cannon. The compressed gas in the line (and in the off-camera tank) is what caused the explosion.
@@nathank7989 ahh, yea that is interesting
I had a potato cannon when I was like eight, and I was showing it to my friends when they were over for a play date. My mom called us up from the treehouse because we had to go, so I want to relieve the pressure in the chamber so I just pulled the valve. Somehow, someway, the CO2 cartridge that was loaded at the time angled itself perfectly and hit my mom square in the forehead.
Was your mom ok?
@@infinitespiral4151 She died
@@sawyerh6838 you could've worded that better 💀
@@Yami_gd true, it made for a poor epitaph
@@sawyerh6838 how do you know?
Me and my best friend in HS made a couple of these back in 01-02. We took them to the local football field during summer break and would sit in either of the end zones and fire potatoes at each other like we were enemy mortar squads. We used hairspray, and eventually swapped to butane because over time whatever additives where in the hairspray would stick to the side of the chamber, would stay lit and we didn't want to melt the sides.
I know i caught this video kinda late but what nobody mentions somehow
is that pvc shrapnel is very dangerous for one particular reason
if it happens to become embedded in a person its a real pain to remove all of it
since it has a similar density as human tissue and does not show up on xrays
how small of a shard does it have to be to not show up on an x-ray or does it just not show up at all?
@@acewmd. As far as I know, it is really hard to see, no matter the size.
@@joetuktyyuktuk8635 oh, well thanks.
Good knowledge..
True, it is much harder. But the army has come up with some pretty amazing methods for detecting non-metallic shrapnel in the last decade and they are making it to the general public
0:15 geez, who would have though that DIY things used masses cause more injuries than things not used by masses :)
Hydrotesting or otherwise testing it is of limited value if you don't know what the peak combustion pressure is. I'd love to see someone do a series of tests with combustion of different fuels and fuel air ratios, potato types and weights, and other factors - with a pressure transducer hooked up to an oscilloscope or other fast measurement device
By the first law of thermodynamics, the pressure within a fixed-size container is proportional to number of particles (molecules of gas) times absolute temperature, so the combustion has to either produce lots of gaseous molecules, or heat the gases by a lot to increase pressure. Like to increase pressure by 10 times (say, from 1 atm. to 10 atm.), the number of co2 and h2o molecules produced by the combustion has to be 5x greater than the number of molecules consumed by the combustion and the whole thing has to heat to 2x the room temperature (~590 kelvin or ~600 °F). Solid explosives do both of those, therefore you get a detonation and a fast-moving pressure wave, but hey, if you put that in your potato canon, you already know what to expect. For anything more conventional we can assume your fuel and oxidiser are both gaseous and at normal pressure of 1 atm. (fuels such as gasoline or methanol are still gaseous, because only the vapours actually burn). With conventional fuels you can't really get a detonation unless you use high compression like inside an engine, so the pressure across your entire container will be more or less uniform, no need to worry about peaks and how to measure them. Also with conventional fuels the number of particles produced by the combustion is pretty close to the number of particles consumed for the combustion, so the only factor that actually increases the pressure is the heat.
Now to answer your question: as long as you use gaseous fuel and oxidiser and don't pressurise them, the only way the pressure inside a potato canon could ever reach 10 atm. would be if your combustion heated the whole thing to 2950 kelvin (4850°F), and 10 atm. is still way below anything shown in this video. Just don't put explosives or pressurised fuel inside and you're good.
@@hitnovak i like your funny words magic man
@@hitnovakmakes sense to me. Maybe just don’t use Oxy Acetylene as your gas.
@@Binford2500 Yeah, pretty much the take-away here. Hopefully people with access to acetylene already know that.
So you mean.... bomb making instructions on youtube?
at exactly 5:51, a thought was processed.... "Will my wife kill me, what do you guys think? Should I buy it"
0:30 I was so confused when I heard my local new’s jingle! I thought they interrupted UA-cam for a weather alert haha
When pressure testing with water you have to make absolutely sure there is no air anywhere in the part or that will be the result, I worked at a water treatment equipment manufacturer for 22 years and we pressure tested tanks about every day and when done properly it makes a loud bang but doesn't send shrapnel flying
Was involved in many pressure tests in construction. Doesn't take much to have a failure. Also have hit a few pieces of PVC pipe when excavating. That stuff grenades uncontrollably. Always cut it with a saw instead of the excavator. I enjoyed others and their potato guns, from a distance that is. I don't trust any explosives 100 percent. Seen the unexpected even in the Army, in a controlled safe environment. Energy/explosives is something to be wary of.
A few years ago, I saw a video of a French youtuber who built a potato canon out of steel that used oxygen and acetylene and with a barrel which had the exact diameter for golf balls. Let's just say it was pretty powerful.
You should probably wear a mask when blasting fiberglass like that. It's not as bad as asbestos, but it still isn't great for your lungs, and this is almost certainly blasts a punch of small fibers all into the air. It's at least not really a carcinogen (that we can tell) but it is still pretty irriating and can cause some asthma/bronchitis like symptoms
I made one many years ago out of copper pipe with an mip on the rear and a threaded pvc cap. The cap was the weak point so any failure would be controlled and directed in a safer direction. It worked really well with aquanet. Also, I sharpened the end of the barrel so it would trim the potato to tight fit as you pushed it in.
Jesus what size pipe did you use. 2 inch copper is 30 bucks a foot, 3in 60, and 4in 90 where i live
@@893R6-w8t 2" barrel 4" combustion chamber. It was 25 years ago, copper was cheaper back then, but I still don't pay anywhere near $30 per foot for 2" type l.
Temperature is what you didn't consider. After a couple of shots the PVC gets hot and at 150F the ratings drop to about 20% of rated pressure.
They need to grab an ASME reference for PVC piping and look at the yield/strain curves and yield stresses vs temperature. The calculation for hoop stress is pretty simple too.
add methanol? lol
WFT are you using for propellant, I shot my spud gun off multiple times in a row. Never got hot, I had also tested it with different length barrels to see how far I could shoot. Best distance was between 500’ and 600’ with a 4” long spud, I used a street female adapter glued into a 3 x 1 1/2 coupling and a male adapter on the barrel. I could split the gun, jam the spud into the male, screw back on, without having to shove the spud down the length of the barrel. A lot easier to load and the male is just slightly smaller than the pipe , so there’s a tiny bit of space for the spud to slide. Also use a tiny amount of WD-40 for barrel lubricant and for propellant, found WD works great and doesn’t get sticky like hairspray.
PS, I’m a master plumber.
@@geneticdisorder1900 I always used the cheapest hair spray I could find (White Rain brand usually iirc). it would get pretty hot after a few shots. but not so hot you couldn't touch it or anything. Just can't fire it too fast
7:23 I like your definition of "safe"
"Glue everything together properly so that the canon rips itself apart and disintegrates into 1000 pieces rather than blowing off the bottom"
you're never going to get 1000 psi out of any kind of potato cannon when its not blocked
It might not be a bad idea to create a deliberate weak point in the cannon, so you have a reproducible failure pathway. Maybe a shallow cut 1/4" wide by 0.05" deep at the front of the large chamber. Make sure the cut profile is rounded to prevent very low failure pressures due to the creation of stress risers in the plastic. A round file might be a good tool.
Dude- I've seen countless honey ads, but when I saw you could save $1000 on something as obscure as a bomb disposal suit, I finally joined and with your discount.
15 years ago my brother and I had a cannon building contest. He built PVC with a grill igniter and some hairspray. I built mine with 1/8th inch thick, 2 inch diameter steel tube, 1\4 in steel wrapped lower for chamber, that runs on Oxygen and acetylene from my cutting torch. It sounds like a tank cannon, turns potatoes to a fine mist, and puts tennis balls thru 1\2 in plywood. I won......
I have made many potato canons in my youth. I always used the pressure rated pipes. I always duct taped mine for looks, not because I thought it was safer. I always used the cheap, old school hairspray. Always sprayed the minimum, always got a good pop, plenty of power and more than enough thump from the end result. Never had a problem. Problem is the types of fuel a lot of idiots think is a great idea to use as an accelerant. Over complicate it, then yes, prepare for potential consequences of an extremely overpowered, over pressured potato canon. Use a practical fuel, properly glue together, use proper pressure rated pipes and you’ll likely never have an issue. It absolutely comes down to the person constructing it properly
When you're relying on atmosphere for your oxygen supply, less is more when it comes to propellant.
Ditto. I tried other things here and there, but determined that hairspray was perfect. I also learned quick not to load more than one projectile...
It's a year later, what happened to the "mgl" version of the launcher you teased at the end?
Before PVC, we used empty tin cans, before they punched them from Aluminum. Taped together, built right, they'd send a tennis ball quite a distance on just lighter fluid. I was in the Air Force, couldn't keep it together, but in a box, with a few cut up to make model airplane tanks, the others could be taped together in minutes, fired to wake everyone up, and tear it down in seconds and look just as surprised as anyone.
Though Illegal, its very papular on the Philippines to celebrate new years though various degrees of safety and quality.
Ahhhhh 1972 again!
@@rdm5190 Oh to be 21 again. I wake up feeling twenty-five, look in the mirror, to shave, that reflection tells me no, I'm not 25 anymore.
Just started watching the video but already I want to clarify that the failure PSI rating for PVC varies WILDLY by ambient temp. At colder temps it becomes quite brittle. This is also true for CPVC (the more yellow variant used for drinkable water supply lines), but less so.
0:23 I love that they used the minecraft tnt sound effect
And the potato cannon from the create mod
I'm a welder and when we where younger at the workplace, we made a potato cannon from steel pipes and used acetylene gas.
My dad and I made a pneumatic tennis ball “cannon” out of schedule 40 PVC when I was a kid. He based it on a design he’d come across while researching where the tank sat under the barrel to shorten the overall length, so it needed two 90° pieces to connect the tank and barrel. One time I thought it would be cool to fill the barrel with water and dump about 100psi. The weight of the water was too much and instead of blowing the water out in a spectacular mist like I’d imagined, it instead just blew the piece between the 90° fittings and the water just drain out the back. The piece that blew out was just inches from my feet and somehow I didn’t get so much as a scratch… afterwards, he tweaked the design by adding two T pieces to increase the area and it still works today, 20 years later
Put it in a kevlar sleeve but don't wrap it tight, it will allow for some expansion and will decelerate the shrapnel since the loose kevlar has time to slow it down
Start by using something like HDPE instead of PVC...
Learn from the pyros.
There is a reason regular pvc isnt used for mortor tubes.
I made the ultimate potato gun. I started with a Gaither Bead Bazooka, an air-powered tool for tire shops to help seat difficult tire beads. It just uses compressed shop air. I unscrewed the diffusing tip and replaced it with a male-threaded copper connector that replaced the diffuser, sweat-soldered to a 14 inch length of 1-1/2 or 2 inch copper pipe. You simply press the open end of the copper pipe into a potato, getting a perfectly-fitting projectile. Charge the Bead Bazooka with compressed air, aim and fire. I get powerful and fairly accurate shots at about a hundred yards.
If you want less distance / power, use less air pressure.
Great video! People often ask us if they should build water rockets from PVC, and we always recommend against it for the reasons you show here. I'll be able to point them to this video from now on.
0:10 To be fair, this is what I call the "Dog-Lion Fallacy" or the "Cow-Shark Fallacy". You see, you're more likely to be killed by a Dog than a Lion, yes, but this is not because lions are less dangerous than dogs. It's because we interact with dogs more. Same goes with Potato Cannons.
Or maybe those who were injured by the hand grenades are dead?
That’s literally the whole joke bruh
You said to glue on the end caps well for safety, but if you expect them to potentially fail it seems like the best place for the cannon to explode.
The m32 rotary potato launcher is a lightweight 40 mm six-shot revolver-type potato launcher developed by a lunatic
another good tip is if you have any doubts, make a deliberate failure point.
knowing where something is going to fail means you can prepare for that failure much better
for instance if you used a hot knife to scratch a weak spot into the pvc, you would KNOW where it was going to fail from, and could point that side away from you, and thereby hopefully be spared the brunt of the failure.
that being said, safety first, and if you have any doubts, maybe just dont do it!!!
Or...wait for it...install an overpressure safety valve!
I used a T fitting and glued the plug in but didn't prime it. After a couple years it blew out so I figured time for a new cannon. It failed while shooting a peach out of it .
very good idea!
Awesome tests! Test a steel one next😬💥😄. Just wondering though, would the hydrostatic pressure test be safer if charged with water instead of air?
Yes. You need to push the water in with hydraulics
Not for this application, because PVC is strain rate sensitive! The material acts differently depending on how fast the strain (due to load or pressure) is applied.
Thus the design may be perfectly sound when pressurized with water slowly, as opposed with a gas bottle or air compressor receiver tank which can pressurize the device rapidly. Just a word of caution.
Do not follow this person's advice, a "steel one" would actually go through your thin piece of metal.
Happened to me, we modded one to accept a propane tank fill, my friend had picked it up for a test shot and walked out from the garage, I looked up and noticed he was filling it a little too much. Just as I began to speak to tell him to not fire, he pressed the igniter, 4" pvc blew into about 1000 pieces, pressure wave hit me pretty good, amazingly my friend didn't get hurt as he was holding it against his body when he pressed the igniter. Got a couple pieces in my mouth as it was open when it happened, but no worse for wear, we laughed it up over beers a little later.
Not as interesting story but my cousin attempted to launch a potato cannon he had made and ended up burning off both his eyebrows lol
Here, hold my beer. Because no good story started with hold my salad.
@@johnwidell8092 that’s got to be the funniest thing I’ve heard today
@@johnwidell8092 beer is what I turned away to get lol
doubt it was because he filled it too much, propane air fuel ratio is about 4% to 8%, more or less and it wont do anything
Ramp it up with seamless steel pipe. Larger diameter of course, then different mixes of fuel and oxygen.
Or you could build a small Sherman tank or a 36" model battleship that has stainless turrets that use propane and oxygen. Wait... that's what I did😉
ive made like 10 potato cannons in "not for pressure" pvc pipes and never had an issue. I had a 3 inch rear and a 2 inch barrel and used a bbq spark switch.
Anyway, I think properly loading it is a huge variable.
When I was a kid there was still a lot of old metal plumbing/oilfield pipe around. And one of my friends made a monster of a potato cannon out of one. We kept putting more and more dangerous propellant in it. And finally one of us had the bright idea of using propane. The back lid flew off like 20 feet hitting my friend in the ribs breaking 3 of them and cracking his sternum. The Dr said if it was just a inch over it could have killed him. We never shot the potato cannon ever again after that.
Butane has both a higher trough burn speed and is far more energy dense than butane c4h8 == 2500btu ft/3 c4h10 == 3000 plus btu/ft3
@@MrDmadness probably that butane canisters tend to only let out a bit at a time, propane ones you can let out a ton of gas pretty quickly because theyre used for much higher btu applications. At least in my country butane is just for lighters and some small portable stove burners, propane is usually used for heating or soldering or the like where the Gas output is much greater. A small butane canister you push to let gas out may only emit a few ml per second whereas a propane canister with a twist valve for industrial or home heating uses could let out a much larger volume. I know because I have a turbo propane torch for plumbing soldering, it’s 30K btu. My butane torch for cigars is like 1500btu. It’s not about the energy density in this case, it’s the overall volume of gas. Teenagers are not measuring how much they’re putting in a potato cannon in any accurate way, I really doubt anyone would weigh or take the volume of the charge unless they’re like a legitimate engineer. Stop trying to call out fake stories or whatever you were getting at when you aren’t really thinking that detailed about the situation lmao. Mr iamverysmart LOL. yes butane is more energy dense, but it will still make a bigger boom if you accidentally add 5x as much volume of propane than butane since the valve lets far more through at a time than the tiny valves on butane cans that are made to refill lighters.
@@mrjjman2010 no dude, I'm a gasfitter with red seal. Butane burns hotter period. While obviously a greater volume will burn hotter this doesn't change the burn temperature just the size of the gas expansion. The reason your torch works is because it's ported and draws in more air.. its essentially a venturi. Also why not just use Mapp for soldering ? Regardless. Butane has a greater Btu output and a faster trough burn speed. Though you are correct about how the volume is dispensed and since both c4h8 and c4 h10 are more dense than air they can both pool
A Canadian here. I have built a couple of spud guns 15 years ago. We use ABS here. All I learned was on a few webpages and a couple of guys at the lake, mostly on the volume ratio to barrel volume and how to measure propane charges. I never used propane. Under arm deodorant spray was my fuel of choice. Right Guard or Axe. (Axe has about 3 times the amount of solvent and butane in it. So you only use 1/3 as much as Right Guard.) My guns were all breach loaders with threaded connectors and a threaded clean out at the butt end. I had interchangeable barrels, 1.5", 2" and 3" . the different barrels all have different sounds. Smaller crack like a shotgun and the 3" gives a good thump. I have only had one safety issue, a gun fired one day due to static and left a mist of potato in the house when the spud hit the ceiling. In cold weather it was always best to load a warm gun indoors before taking it outside to fire otherwise there is a problem with the mixture. Some of the videos used speed guns to check velocity and one guy had a device to rifle the bore which increased the accuracy significantly into tight groups. He made 2" x48"ABS which I think he sold a few online.
my late father-in-law built one ages ago, and used it to blast the walls off a small, abandoned cottage into oblivion!!
he was just one inciting incident away from becoming a supervillain!! he was a really cool guy, gone way before his time, he is missed... the structure of the cottage is still standing, and I think he'd get a kick out of the fact that we shot a thrash metal music video in it...
Wouldn’t it be safer to purposefully leave it weaker towards the back and make sure to no one stands behind the cannon when firing? Like, use the string PVC pipe strengthened with fiberglass except in the back.
Intentionally planned breaking points are always prefferable above chaotic pattern breakage.
Or you could just duct tape the rear cap on so it would blow off before the whole thing goes kaboom.
You need an expandable mesh. To catch fragments you slow them down gradually. If you try to contain them at their initial velocity you'll need rigid containment. This is how kevlar body armor works, it's basically a tightly woven fabric (net) with room to move and stretch. Still, pointy bullets will penetrate it so a rigid containment vessel might be wise.
You have to do all the reinforcement but engineer a failure point at the back. If you double up on reinforcement especially with chicken wire, it just becomes more shrapnel. Make a sort of burst point in the back like carving a slight groove in a circle in the back
Where can I find the next video he said at the end of this one? That street sweeper like gun is pretty cool. I can't find the video, anyone?
Very cool, thanks for including my spud tank! Your tests are great, and a good reminder what can go wrong if someone isn't careful with these!
3:38 When the pressure at the cylinder is 200 it will not be 200 at the pvc pipe under the dynamic conditions of your experiment . The gas is travelling along a very small bore long tube . You have to increase pressure VERY slowly for reading to have any meaning.
This man gets it. For the electric crowd, the PVC pipe is like a capacitor being filled through a resistor from a voltage source - we would have to calculate the air mass (charge) that had already flowed into or is currently flowing into it to infer the pressure.
Rescue Randy is such a trooper! He’s been through so much for the sake of science, and yet he’s still going strong for what he believes in!
I made a "blow gun" out of a medium sized fire extinguisher to shoot marbles at stray dogs and raccoons. It recharges from an ordinary compressor to 195 psi through a short air valve screwed into the tank, secured by a nut on the inside. I use a lever valve to "fire" it. I've used it with homemade "spears" made of PVC and sharpened spikes as well. They fit over the smaller PVC tube that I use to shoot the marbles with and I gave them fins to help stabilize their flight. Not long ranged but fun with a backyard target.
Literally built one a week ago and the end cap exploded into my hand! My fingers are still struggling to bend and hurt alot! If only this video was posted 7 days earlier...
For a few years now I don't glue on the end cap properly on purpose so that in the case of to much pressure buildup there is a place that gives and the pipe doesn't explode in my hip or cheek.
It's scary how often people build something without any predetermined breaking point, safety valve or whatever is suitable for the built...
That's not too bad an idea, but a pressure relief valve or burst disc is a better one. They are considerably safer and will act at a known pressure. They can be had on Amazon for under $10.
I was about to say, like a pressure cooker valve
The power of the potato is unmatched, as an irish person I can confirm, if that wasn't obvious.
There’s no way you took a bong rip or if your potato cannon. I love you Kevin
I recently made my third (and largest at 6'4" long) Potato cannon. I've thus far made all of them combustion style out of black schedule 40 ABS. The only issue I've had as far as explosion goes was due to an ignition system mounting bolt that I (very stupidly) mounted through the blast chamber wall. However, instead of completely shattering or sending shrapnel everywhere, it cracked about halfway around the chamber in an arc shape and singed some arm hairs in the process.
I was recently trying to figure out pressure levels created by one of these cannons and would be interested to see you explore this a bit as well.
I have a few videos of my current and past cannon models on my own youtube channel for reference.
7:45 You still had a lot of air in it.
Now I think about that, using a weak end cap seal or other part could be a safety device for overpressures as a controlled release. Like the M1 Abrams blowout panels.
It hurts like hell as well.
But then again I was using o² acetylene torch for fuel and was shooting potato half a mile