Home made PCP airgun

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Sorry but your dad needs to take a look at what you are substituting for a safe air gun, I see nothing good happening with this design of yours. I give you credit for trying but the air pressures you are using can cause fatal injuries. If projectiles can go through cinder blocks where is that energy coming from? Using Plastic pipe for a PCP reservoir is asking for trouble, you already stated that one pipe exploded on you, wasn't that enough of a warning for you, or your Dad? Please take care and listen to the advice of very experienced people who have a lot of knowledge between them, what you are playing with is very dangerous. All the best, Neil.
 
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"Drunk"USABRO, maybe it would also be interesting for you to find out with how much of a TNT equivalent you are dealing while filling/handling that PVC airtube :)

The link below might help you to calculate and maybe reconsider if to move further with those engineering experiments, which are of course cool, bet VERY dangerous considering your current experience and the matherials you are dealing with (tip: a normal hande grenate has about 150 grams (0.33 pund) of TNT). 

http://www.nigelhewitt.co.uk/diving/maths/tank.html 
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The link doesn't work.
 
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Wait until you have an engineering degree, then try to build one of these. Until then, get a Benjamin Discovery or even one of the little CO2 powered pistols. Drain the air out of this and put it on a shelf. You're playing with bombs. I'm not kidding. You're going to hurt yourself, or someone else. I know that at age 16 your frontal cortex hasn't finished developing so cause and effect relationships don't always form, but you need trust me on this. Show this thread to your father. He'll either ground you for 2 years, or shell out the money for a real gun. If he's smart, he'll buy the gun and enroll you at a good engineering school.
 
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High pressure air is extremely dangerous and is not something to mess with unless you have experience in that field. I make LDC's and shrouds on a lathe and have a lot of experience in design, I have been asked many times to make air tube extensions for customers, my answer is always the same, NO. I do not mess around with HPA, it is an area that only people with specialized knoweldge should play with. You can make it safer by getting rid of the gun you have made. If finances are a concern to your father then he should consider the risks you are putting yourself at and the medical costs that could be incurred if you continue along this path. You need to do more than consider the advice people are giving you, you are playing around in a very dangerous area and not one to be taken lightly at all. If you were only using 50psi my concerns would be reduced but would still be there, compressed air can be extremely dangerous and only people experienced in HPA should be going there, all the best, Neil.
 
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"NeilClague"High pressure air is extremely dangerous and is not something to mess with unless you have experience in that field. I make LDC's and shrouds on a lathe and have a lot of experience in design, I have been asked many times to make air tube extensions for customers, my answer is always the same, NO. I do not mess around with HPA, it is an area that only people with specialized knoweldge should play with. You can make it safer by getting rid of the gun you have made. If finances are a concern to your father then he should consider the risks you are putting yourself at and the medical costs that could be incurred if you continue along this path. You need to do more than consider the advice people are giving you, you are playing around in a very dangerous area and not one to be taken lightly at all. If you were only using 50psi my concerns would be reduced but would still be there, compressed air can be extremely dangerous and only people experienced in HPA should be going there, all the best, Neil.
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I know it's dangerous, but then tell the kids who play with water rockets to stop using them too haha. People using water rockets pressurize to 150 psi on a regular basis, and their rockets are made with soda bottles. The world record water rocket launched to 2700 feet was pressurized to over 1000 psi. And some are soda bottles reinforced with carbon fiber, or using FTC tubing.
The only extra danger I see is this type of plastic can be shrapnel rather than just tearing. Kids make spud guns and air cannons all the time without injury. Not that an accident couldn't happen but still.

So then we all shouldn't be using walmart aircompressors that can create 150 psi?

Oh and I've made bombs too! I once filled a 2 liter bottle with oxygen and hydrogen in a 1 to 2 ratio from electrolysis and detonated it with a small model rocket igniter connect to a texas instruments timer that I used for parachute deployment in the past.
 
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Water rockets also use water which is a lot safer than just compressed air, your cavalier attitude is going to get you hurt, you need to listen to people with experience and knowledge in this field otherwise you are going to get hurt badly. You take the advice you are given too lightly which shows your very limited knowledge in this field, do not mess with areas that you are not trained in, it will only end badly. you have been warned by multiple people on here who are fully aware of the dangerous area you are playing in, please pay attention to the advice you are being given and do not come back with some some excuse for what you are doing, maybe as someone else mentioned, you should let your dad read some of the comments on here before you respond to anything else, Neil.
 
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Spud Guns and Canons are actually regulated by the Alphabet org. They use an combustion explosion that propels the projectile. The Alphabet org can really ruin your day about it if they want to. I know that everyone builds them and plays with them, but they're illegal believe it or not. If your barrel isn't long enough, you can run afoul of state laws regarding short-barrel shotguns too.

The guys that built the world record bottle rocket were aerospace engineers if I remember correctly. They weren't 16 year old boys. If you watch their videos they tested their CF wraps and pressurized them from about 200ft away and contained them in metal cages to contain the shrapnel. They experienced multiple 'sudden rapid dis-assembly' incidents captured on video. Kids water bottle rockets are very different from what those guys were doing with pressurized soda bottles. Water bottle rockets use compressed water. If the water bottle ruptures, it becomes a squirt gun. No big deal. Worst case scenario is the rocket cracks and water leaks out. 

Air compressors use a welded steel pressure vessel designed by a certified engineer, tested to ASME standards with a calculated design safety factor included in the design. Even then, you'll notice that they all have a drop-dead date stamped on them. They will eventually fail after cyclic loading. This is why the DOT, OSHA, ASME, EU and numerous other governing bodies have standards for pressure vessel designs, testing requirements and lifespans. Did you ever wonder why the person who drives a train is called an 'engineer'? It's because back in the day, steam locomotives were powered by enormous pressurized cylinders of expanding steam. It required a freaking engineering degree to understand how they worked, and keep them working. Before the creation of ASME standards they would routinely explode killing many many people.

Again, I applaud your curiosity and ingenuity. I've done plenty of stupid things myself that could have killed me involving hydrogen, dry-ice, gasoline, styrene, kerosene, who knows what else. I survived, right? True, but you won't get warnings from the kids who blew themselves up. They don't get to participate in the survey. It's hard to raise your hand if you don't have one. You can't say 'aye' if your jaw is missing. Trust me and learn from my statistics beating experiences. Don't do this. By the way, I do have 2 engineering degrees.
 
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I say kudos to you. Not just anyone can go in the garage and make an air powered rifle that actually works regardless of the dangers involved. 

Im certain this kid understands the risks involved after one of his guns exploded. Yes, you got lucky. Remember that my guy. 

It's easy to sit here and lecture about safety, but what about the Wright brothers? THEY WANTED TO FREAKING FLY!!!! You know how many naysayers they must have had, but the world today is glad they believed they could do it. 

what about Archimedes? Compound pulleys? HA!!!!!! Witches work along with that math nonsense!! 

This kid is an out of the box thinker. So long as he lives to make it through school you may be talking to someone who could change the world in the not so distant future. Let's not stifle him. 

No risk, no reward, bottom line. Yes you are quite cozy with danger every time you fill, shoot and handle that thing, but you got to start somewhere. He may be the next RAW or EdGun or Thomas or NASA who knows!

Try an app called Chrono Connect Lite. The science behind it is sound, but it won't be 100% in comparison to an actual Chrono, but it will give you an idea. Some people struggle to set the phone up correctly to use the app properly, but I don't think you will end up having a problem figuring it out. 
 
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Something else to consider: plastic materials exhibit a property referred to as 'creep'. When you put plastics under a load they will deform ever so slightly. Under continuous load they will permanently deform. When that happens, the strength of the plastic decreases while the load remains the same. This means that less material is resisting the stress that was too much to begin with. This results in even more, and faster deformation. Soon, you have catastrophic failure. You see this frequently with plastic bottle caps. They'll crack around the threads because it was tightened too much. This is why you don't see pressure vessels made out of plastic. It's a bad idea. The good thing about plastic though is that if it's thin enough it will tear releasing the pressure rather than explode like a shrapnel bomb. Some materials are better than others for pressure vessels. Steel is good. Cast Iron, is bad.
 
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Thanks guys. I'm trying to convince him to let me buy one, and I'll show him these comments. Even if those people were areospace engineers who built that rocket, there are plenty of kids including me who have built them to go 300+ feet high. I think the reason they're less dangerous is because filling and launching is done at a distance from living things.
However, I play with dry ice bombs too, and they're on the same level of danger. But I try to be careful, and I think I may dismantel my gun until I get strong metal pipe, so I'm not temped to play with it, if it's as dangerous as the vets are saying.

Yes cast iron is brittle. I'd find it hilarious if someone made a scuba tank out of cast iron :)
 
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"Swing360"I say kudos to you. Not just anyone can go in the garage and make an air powered rifle that actually works regardless of the dangers involved. 

Im certain this kid understands the risks involved after one of his guns exploded. Yes, you got lucky. Remember that my guy. 

It's easy to sit here and lecture about safety, but what about the Wright brothers? THEY WANTED TO FREAKING FLY!!!! You know how many naysayers they must have had, but the world today is glad they believed they could do it. 

what about Archimedes? Compound pulleys? HA!!!!!! Witches work along with that math nonsense!! 

This kid is an out of the box thinker. So long as he lives to make it through school you may be talking to someone who could change the world in the not so distant future. Let's not stifle him. 

No risk, no reward, bottom line. Yes you are quite cozy with danger every time you fill, shoot and handle that thing, but you got to start somewhere. He may be the next RAW or EdGun or Thomas or NASA who knows!

Try an app called Chrono Connect Lite. The science behind it is sound, but it won't be 100% in comparison to an actual Chrono, but it will give you an idea. Some people struggle to set the phone up correctly to use the app properly, but I don't think you will end up having a problem figuring it out.
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Thanks so much. Yes I do understand the risks. One of these things exploding could cause permanent eye injury or blindness plus shrapnel wounds and/or lacerations. And as someone here said air entering the bloodstream, and property damage.
NeilClague said:
Water rockets also use water which is a lot safer than just compressed air, your cavalier attitude is going to get you hurt, you need to listen to people with experience and knowledge in this field otherwise you are going to get hurt badly. You take the advice you are given too lightly which shows your very limited knowledge in this field, do not mess with areas that you are not trained in, it will only end badly. you have been warned by multiple people on here who are fully aware of the dangerous area you are playing in, please pay attention to the advice you are being given and do not come back with some some excuse for what you are doing, maybe as someone else mentioned, you should let your dad read some of the comments on here before you respond to anything else, Neil.
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Well you may think that water rockets use water, but they only use about 1/4-1/3 water. That leaves liters and liters of air compressed to easy 13 bar.


And I did the calculation of joules for the gun. 12 cubic inches is equal to 0.197 liters. Times 16 bar X 450 is 1415.84 joules. Is that a lot of energy? I don't know.1415.8423296
So people seem to be saying that 1 gram of tnt produces 4184 joules of energy. Well then my gun contains the equivalent of 0.33839 grams of tnt when pressurized to 230 psi. An average shot I take is at 110 psi. 
 
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I'd think a Benjamin 392 or 397 would do well for a rifle. A Crosman 1377 or 1322 with a Carbine stock would be another option. If you want to go PCP, a Discovery is a good place to start. The Marauder Pistol is also a good option. You won't be putting holes in cinderblocks, but you also won't be risking death and dismemberment.

Crosman 1377 with Carbine stock:$100
http://www.pyramydair.com/s/pre_packaged_deals/Crosman_1377C_PC77/561

Wally World and Amazon have the 392 for $144.
http://www.walmart.com/ip/Benjamin-392-.22-Air-Rifle/5420297
http://smile.amazon.com/Benjamin-392-Action-Variable-Rifle/dp/B002J1OZ8G/ref=sr_1_1?ie=UTF8&qid=1449784191&sr=8-1&keywords=benjamin+392

Benjamin Discovery/Pump Combo: $325
http://smile.amazon.com/Crosman-Benjamin-Discovery-Pre-Charged-Pneumatic/dp/B0018LETH0/ref=sr_1_1?ie=UTF8&qid=1449784274&sr=8-1&keywords=benjamin+discovery+combo

Benjamin Marauder Pistol Combo: $575
http://www.pyramydair.com/s/pre_packaged_deals/Benjamin_Marauder_PCP_Air_Pistol/4738


 
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