Guy Makes 3-D Printed Rail-Gun, Now We Just Need Power Armor - Polidicks

To be fair people should not expect a homemade handheld rail cannon to be effective.

We actually have a 3D printer in our Drafting class, and our teacher explained that it's illegal to make entire firearms with it but you can still make individual components. If someone wanted, they probably could construct an entire functioning pistol or something with a bit of effort.

isnt that the fallout laser rifle?

[QUOTE=AlexGT;48931783]We actually have a 3D printer in our Drafting class, and our teacher explained that it's illegal to make entire firearms with it but you can still make individual components. If someone wanted, they probably could construct an entire functioning pistol or something with a bit of effort.[/QUOTE] You can create a somewhat functional pistol by hand too. The problem is that if you use consumer grade printers, your gun will last one shot and best case will simply break, worst case it will also hurt you in the process. It's been done before.

The latest design of the 3D printed rifle can last a number of shots. It's not big security concern, to be honest. It requires a fairy well calibrated machine and milling or cnc work is still easier. Printers are admittedly cheaper nowadays, but the machines at the bottom of the price spectrum are pretty tiny in terms of build envelope. It's legal to make firearms with it, depending where you live

I'd love to see those caps powering a coilgun [video=youtube;TWeJsaCiGQ0]http://www.youtube.com/watch?v=TWeJsaCiGQ0&ab_channel=JasonMurray[/video]

[QUOTE]The railgun uses 6 300J, 350V, 5500uF capacitors which combined weigh 20lbs and can deliver >1050V and 1.8kJ of energy to the projectile.[/QUOTE] I think what they meant to say is it can hypothetically deliver 1.8kJ to the projectile. If it had a real muzzle energy of 1.8kJ it would be [url=https://en.wikipedia.org/wiki/Muzzle_energy#Typical_muzzle_energies_of_common_firearms_and_cartridges]equivalent to a rifle firing 5.56×45mm rounds[/url], and you can tell from the video it's kind of a mess. It appears to just be melting the projectile, didn't see any real damage to the target, so the energy is not really well employed.

[QUOTE=taipan;48929858]Capable of firing plasma. Euhh what?[/QUOTE] The body of a flame is technically plasma, it's not just high-energy scifi glow goo. It's just another aggregate phase that needs a lot of energy, which something like a railgun can probably provide, even if the phase shift is short lived.

Now what would be the result if you took all that electricity and instead of using it for shooting a projectile, wired it to a sufficiently sturdy laser (aka a laser that won't self destruct under that level of voltage)?

[QUOTE=Elspin;48931955]I think what they meant to say is it can hypothetically deliver 1.8kJ to the projectile. If it had a real muzzle energy of 1.8kJ it would be [url=https://en.wikipedia.org/wiki/Muzzle_energy#Typical_muzzle_energies_of_common_firearms_and_cartridges]equivalent to a rifle firing 5.56×45mm rounds[/url], and you can tell from the video it's kind of a mess. It appears to just be melting the projectile, didn't see any real damage to the target, so the energy is not really well employed.[/QUOTE] The problem with railguns is that you need really really fast switching transistors capable of being controlled with low gate voltages yet handling stupidly high burst voltages through the drain rail. Designs for high power applications commonly use stacked arrays of scaling transistors, configured for fast switching with the highest tier being the low voltage gate transistor and the lowest in the ladder being used for taking the brunt of the electrical and thermal load. Otherwise, as seen here, you just waste most of the energy in the form of heat. Also, the plasma wears the rails down. They have to be replaced and maintained frequently, or coated in expensive materials to slow the abrasion rate. [QUOTE=TheMrFailz;48932054]Now what would be the result if you took all that electricity and instead of using it for shooting a projectile, wired it to a sufficiently sturdy laser (aka a laser that won't self destruct under that level of voltage)?[/QUOTE] Still wouldn't be able to do much. lasers have to be collimated for certain distances. Or focused. Forget exact terms. Me and a friend had an idea of doing something similar and using our club resources (yay, using leadership positions to fund choice projects!) to get it built. Our university didn't really approve, but we had some fancy switching transistors and a chinese friend managed to get us a few grocery bags full of cheap 400v capacitors :(

[QUOTE=TheMrFailz;48932054]Now what would be the result if you took all that electricity and instead of using it for shooting a projectile, wired it to a sufficiently sturdy laser (aka a laser that won't self destruct under that level of voltage)?[/QUOTE] The only type of laser that would surive that is a gas discharge laser, the conversion efficiency is very poor so it's only going to be about the same output power, except it doesn't penetrate anything.

[QUOTE=paindoc;48932093]The problem with railguns is that you need really really fast switching transistors capable of being controlled with low gate voltages yet handling stupidly high burst voltages through the drain rail. Designs for high power applications commonly use stacked arrays of scaling transistors, configured for fast switching with the highest tier being the low voltage gate transistor and the lowest in the ladder being used for taking the brunt of the electrical and thermal load. Otherwise, as seen here, you just waste most of the energy in the form of heat. Also, the plasma wears the rails down. They have to be replaced and maintained frequently, or coated in expensive materials to slow the abrasion rate.[/QUOTE] There's plenty of problems beyond that but honestly all that really needs to be said is a rail gun doesn't belong in your hands. They would have been much better off using all that power for a coil gun.

[QUOTE=Elspin;48932155]There's plenty of problems beyond that but honestly all that really needs to be said is a rail gun doesn't belong in your hands. They would have been much better off using all that power for a coil gun.[/QUOTE] Yeah, didn't see a need to go here. Coil guns or hybrid coil/railguns are better.

[QUOTE=Bat-shit;48929752]And that probably isn't even illegal to make..? How's the law side of things when it comes down to manufacturing guns for self, or home defense anyway? And specifically 3-D printing them. Now that thing itself is huge, but get yourself a compact design with nice materials and print out a home defense tool.. Jesus Christ, I begin to question what am I even talking about, but it's not that much worse off than a conventional firearm. I wouldn't wanna be on the receiving end of either of those things, much less break into a home.[/QUOTE] It is totally legal in the United States to make weapons at home nor are you required to register them or inform the government, provided they do not fall under the classification of Title III firearms aka fully-automatic/have a barrel shorter than 16". Even still, it is legal to manufacture Title III weapons assuming you register them and get a Title III license for them. You just can't sell them. I'm pretty sure theres a way to sell personally made firearms, but i dont know the specifics, so i'm not going to pretend like i know. as for Rail/Coilguns.... I assume they'd have to meet a lethal velocity requirement individualized for the projectile to even be considered weapons at all. Even then, if it's not fully-automatic or the barrel/coil is shorter than 16", no worries.

[QUOTE=General;48930283]So in theory how powerful can this weapon be?[/QUOTE] 1.8kilojoules is applied to the projectile. That is reasonably powerful IIRC.

[QUOTE=NeverGoWest;48932415]1.8kilojoules is applied to the projectile. That is reasonably powerful IIRC.[/QUOTE] Too bad virtually none of that is being converted into kinetic energy, with most of it being lost as heat and ablation of the rails and projectiles.

[QUOTE=ExplodingGuy;48932516]Too bad virtually none of that is being converted into kinetic energy, with most of it being lost as heat and ablation of the rails and projectiles.[/QUOTE] Reeks of some sort of design flaw. Now I know what to do with all my electronics equipment stuff! I can put together the first railgun for plinking purposes!

[QUOTE=NeverGoWest;48932606]Reeks of some sort of design flaw. Now I know what to do with all my electronics equipment stuff! I can put together the first railgun for plinking purposes![/QUOTE] Or more likely, if you don't know what you're doing, kill yourself when you incorrectly discharge 1.8kJ of HV power right into your body.

Honestly you could make a far more dangerous weapon by attaching those capacitors to a metal stick and poking people with it :v

Looks like one of the prawn guns from district 9

[QUOTE=Kyle902;48935669]Honestly you could make a far more dangerous weapon by attaching those capacitors to a metal stick and poking people with it :v[/QUOTE] or making a really wicked taser [editline]19th October 2015[/editline] although the wiring for the probes would have to be like 14AWG haha

[QUOTE=Biotoxsin;48930421]The projectile seems comparable in energy to one which would have a force somewhere between that of a .357 mag and a 7.62×39mm round. (Closer to the 7.62) 1.8 kJ isn't insane, but it would still kill easily. Seems more like a novelty at the moment, but it is still badass.[/QUOTE] You're joking right? Either of those rounds would blow the cantaloupe up and keep on going, these slugs don't even pass through the cantaloupe. I think you're confusing the joules of energy available to launch the projectile with the actual joules of energy the projectile is imparting upon the target when it hits, which we have no way of knowing unless we're able to get a mass of the projectile and a projectile speed at time of impact. That being said it's obviously very underpowered for what it is, which is really sad because it's amazing, but until we get some sort of hypercapacitor with a super high energy storage vs capacitor body size ratio we'll never see 'small arms' railguns.

Would there even be an advantage to having "small arms" railgun? Even if it was as effective as a handgun in force, what would make it better than a normal gun?

[QUOTE=itisjuly;48942988]Would there even be an advantage to having "small arms" railgun? Even if it was as effective as a handgun in force, what would make it better than a normal gun?[/QUOTE] I would imagine that you could scale the firepower, or the velocity of the projectile at the risk of fucking ruining the weapon. Don't take my word for it though, I don't know shit about rail guns, I'm just fascinated by them.

[QUOTE=ossumsauce;48932311]I'm pretty sure theres a way to sell personally made firearms, but i dont know the specifics, so i'm not going to pretend like i know.[/QUOTE] The only real way to do this is to buy a completed receiver and build a rifle from it, because that's usually the part treated as "the gun". You're right about registration. [editline]20th October 2015[/editline] [QUOTE=itisjuly;48942988]Would there even be an advantage to having "small arms" railgun? Even if it was as effective as a handgun in force, what would make it better than a normal gun?[/QUOTE] Close combat ultra silenced weaponry?

[QUOTE=itisjuly;48942988]Would there even be an advantage to having "small arms" railgun? Even if it was as effective as a handgun in force, what would make it better than a normal gun?[/QUOTE] The short answer is there really isn't one. Railguns have an interesting application in extremely high power navy carriers but in handheld terms it's just not possible with current technology to ever get anywhere to close to the reliability, power, and compact size of a real gun. It's literally physically impossible with the energy density of capacitors/batteries. Coil guns at least have some interesting possible advantages, for example the very [i]low[/i] wear on the gun (whereas rail guns fuck themselves up real bad constantly). Still though, coil guns are not going to get anywhere near as powerful as real guns for many years. Even if you could build a near perfectly efficient railgun/coilgun in terms of efficiency of converting electrical energy to muzzle energy, the capacity of capacitors and batteries is just too low to make them viable. There are some limits you can engineer around, but there are some that are completely literally physically impossible to pass without improved base components.

[QUOTE=Elspin;48945374]The short answer is there really isn't one. Railguns have an interesting application in extremely high power navy carriers but in handheld terms it's just not possible with current technology to ever get anywhere to close to the reliability, power, and compact size of a real gun. It's literally physically impossible with the energy density of capacitors/batteries. Coil guns at least have some interesting possible advantages, for example the very [i]low[/i] wear on the gun (whereas rail guns fuck themselves up real bad constantly). Still though, coil guns are not going to get anywhere near as powerful as real guns for many years. Even if you could build a near perfectly efficient railgun/coilgun in terms of efficiency of converting electrical energy to muzzle energy, the capacity of capacitors and batteries is just too low to make them viable. There are some limits you can engineer around, but there are some that are completely literally physically impossible to pass without improved base components.[/QUOTE] Its not so much the capacitors that are the issues, or batteries and such. You could still use battery/capacitor packs as magazines, and make the weapon an anti-material type weapon like the Barrett M82/M107. The magazines would be large, but with the usage of film capacitors leakage wouldn't be a problem. The problem is that we are held back by how much current we can dump into the weapon and how fast we can dump said current, due to limitations of the switching transistors used. The stackable transistors are an idea, but even these aren't fast enough. This guy is using electrochemical capacitors, but I wonder if using film capacitors would work better due to their lower internal ohmic resistance and much lower leakage rate. Pretty sure properly constructed can still dump current just as fast too, but they are much much pricier. Hell, I wonder if the Naval design uses film capacitors since those would work better for charging and leaving the capacitor charged (film caps are the choice for sample-and-hold circuits, it would make sense). While the capacitor and battery capacity issue does not help, it is only one of the many issues we face with these weapons. I'm interested to know what materials science magic the Navy worked to even make the idea of a railgun on a DDG feasible, they'll still have to refurb it from time to time and I'm pretty sure part of the forecasted cost includes bringing a spare set of rails. [editline]20th October 2015[/editline] to be fair, all I know about capacitor types and differences in their fundamental properties comes from analog synthesizer design manuals

[QUOTE=Biotoxsin;48931097]If you go onto youtube, there's a ton of hilarious/terrifying videos of people doing this[/QUOTE] that sounds fun

[QUOTE=paindoc;48946391]Its not so much the capacitors that are the issues, or batteries and such. You could still use battery/capacitor packs as magazines, and make the weapon an anti-material type weapon like the Barrett M82/M107. The magazines would be large, but with the usage of film capacitors leakage wouldn't be a problem. The problem is that we are held back by how much current we can dump into the weapon and how fast we can dump said current, due to limitations of the switching transistors used. The stackable transistors are an idea, but even these aren't fast enough. This guy is using electrochemical capacitors, but I wonder if using film capacitors would work better due to their lower internal ohmic resistance and much lower leakage rate. Pretty sure properly constructed can still dump current just as fast too, but they are much much pricier. Hell, I wonder if the Naval design uses film capacitors since those would work better for charging and leaving the capacitor charged (film caps are the choice for sample-and-hold circuits, it would make sense). While the capacitor and battery capacity issue does not help, it is only one of the many issues we face with these weapons. I'm interested to know what materials science magic the Navy worked to even make the idea of a railgun on a DDG feasible, they'll still have to refurb it from time to time and I'm pretty sure part of the forecasted cost includes bringing a spare set of rails. [editline]20th October 2015[/editline] to be fair, all I know about capacitor types and differences in their fundamental properties comes from analog synthesizer design manuals[/QUOTE] This is not correct, the capacitors/batteries are an issue. Look at that massive fucker, a rifle which is fairly light and compact packs way more punch than this thing would even if it delivered the full capacity of energy with 100% efficiency and it can do it over and over again replacing 10s of shots instantly. Capacitors simply cannot hold enough power to deliver many shots at a comparable power to guns. Basically what it comes down to in any weapon is Energy in * efficiency = energy out, where energy in can be a wide variety of types and energy out is the kinetic energy of the projectile at the muzzle. The energy in you can get from capacitors at the size is just not good enough to be a viable at a portable size. The construction of your capacitor based gun literally does not matter because your efficiency is not going to over 100%, and capacitors energy density can only be so good. The fact that these weapons are also much harder to make and easier to ruin from environmental conditions is just the icing on the nasty cake of electronic weapons. Basically here's your answer in number form of why capacitors (in their current state, not necessarily the future!!) can't possibly be viable: Specific energy of gunpowder: 3MJ/kg (and easily compacted to harness) Specific energy of capacitors: 0.000036MJ/kg (much more difficult to harness)

[QUOTE=Elspin;48946712]This is not correct, the capacitors/batteries are an issue. Look at that massive fucker, a rifle which is fairly light and compact packs way more punch than this thing would even if it delivered the full capacity of energy with 100% efficiency and it can do it over and over again replacing 10s of shots instantly. Capacitors simply cannot hold enough power to deliver many shots at a comparable power to guns. Basically what it comes down to in any weapon is Energy in * efficiency = energy out, where energy in can be a wide variety of types and energy out is the kinetic energy of the projectile at the muzzle. The energy in you can get from capacitors at the size is just not good enough to be a viable at a portable size. The construction of your capacitor based gun literally does not matter because your efficiency is not going to over 100%, and capacitors energy density can only be so good. The fact that these weapons are also much harder to make and easier to ruin from environmental conditions is just the icing on the nasty cake of electronic weapons. Basically here's your answer in number form of why capacitors (in their current state, not necessarily the future!!) can't possibly be viable: Specific energy of gunpowder: 3MJ/kg (and easily compacted to harness) Specific energy of capacitors: 0.000036MJ/kg (much more difficult to harness)[/QUOTE] Eh probably should wait until they start making Graphene capacitors before they can store energy in smaller spaces.