Simple mass-producable gun

[cheeseboy]

while I voted for 'Lousy.....don't bother with mass producible guns!' I agree that this gun would be good for getting people interested in science, the best thing to do would be to bring in a bad-a$$ copper cannon and then the kids will want to make their own and they will learn valuable skills in the process as was earlier mentioned. The only thing is that the kids are 14 and 15, well they ain't kids no more are they? for the same price you can make a hammer valve as was mentioned earlier by john, the kids in your club are probably smart, and would be able to handle it. I think you are Doing a great job limbeh keep it up and keep it safe!

P.S being 13 I shouldn't be writing like that, I'm younger than the kids in your group!

[brogdenlaxmiddie]

I thought pop bottles were safer in that they don't explode like PVC but rather rip like ABS?

I understand where your coming from that, but perhaps you should take some dry ice and water, put it in a soda bottle, and seal it, and throw it far away from you and see what happens. These bottles don't simply rip open slighty and leak out air, they explode.

PS- I don't know if anyone else mentioned this but I didn't have the time to read the other posts.

[POLAND_SPUD]

one way to turn it into something good is to use malleable iron fittings, pipes and a metal BV...
in this way you wouldn't have any problems with safety..

ohh and it could be upgreaded to a QEV gun using the same parts - so it would be cheaper in the long run

[psycix]

The chamber should be constructed out of pressure rated PVC. Not a coke bottle.
Bottles are unpredictable and could blow, and if the thing blows in the hands of a kid you're in trouble. Even if PVC blows more catastrophically, the PVC has a near 100% chance not to blow when you keep it under its rating (and do not drop it).
Pressure rated PVC or even better; metal; is necessary to ensure safety, along with a pressure gauge (possible on your pump) and a safety pop-off valve.

When a gun is put in the hands of a non-spudder, extreme caution must be taken. Some people do not understand the power of air.

[john bunsenburner]

Persoanally i think you should not do this out of one reason. Not because you are making something wrong not because i think the amounts of "science" YOU used and applyed in this are absolutely pathetic, no i think you should stop because of your absolutely wrong understanding and concepts with science. You are lucky to be on the other sie of the world because its hard to get me this angry and survive... What you said disqualifies you from everything to do with not only using and learning science but teaching it. As you are most probably confused i will add you quote here:

...but as trigun has said, its the 1 or 2 hardcore destructive ones that are the most dangerous ones that I have to prevent.

Saying thatyou will prevent the hardcore dangerous ones goes to show your plain ignorance, why? Because these few hardcore ones are the only ones that will ever manage to become anything worthwhile when it cmes to their scientific qualifications! Look at me, i am as hard core as can get. i have pretty much every high explosive in my cellar, i know the periodic table by eart, i know what the teacher will say once he writes the days topic on the board. I am the youngest in my country to ever join the national chemistry olimpiad being under the 42 best chemists that are not on a university and under twenty. And ym age? I am 13 years old! Am i hard core? Yes. Will i grow up to do anythign scientific? Definately, though how good it will be still needs to be found out. What you are doing is limiting these few hardcore students, so please stop it as you are being unfair. If you where to be any good you wouldn't do it at all but your to ignorant to do so, if you want to help these children get them a good and experienced teacher as a tutor or mentor or what ever, but please don't stop them enjoying science.

[Biopyro]

Some of the kids who might be regarded as "hardcore destructive ones" really are those with unused potential - especially if they seem fairly intelligent with it.
Just make sure to teach them the saftey and to respect the power of what they have.

[maverik94]

I like the Idea, but I agree that you need to use a better air chamber, not only do pop-bottles not hold much pressure, but also, they get weaker every time that you pump them up. You could use some 1 1/4 inch pvc for a chamber, thats what I usually use, and my newest gun that I used that is POWERFUL (for 50 psi). As far as the age thing goes, 14-15 year olds? Sounds ok to me, Im 14 and my parents and I am fine with me shooting my pneumatics. Obviously you have to emphasize safety, but as you said, you have been. I really think this is a good science project for learning about pressure and ratios. You could even have the students figure out the volume of the chamber/ barrel and figure out strength. I agree with the fact that you dont let the kids take the guns home, but I personally think that you should encourage them to optimize their designs, thats how we learn, right? But anyway, cool idea, and that's why its great living in th usa, we dont have these restrictions. But again, I guess in a big metropolitan area like singapore, it's different.
Also, you have to make sure that the students appreciate the power that they have in their hands. I first thought that my little ball valve pneumatic was a toy, but I now know better, It is a weapon, and should be treated as such.

[limbeh]

I did something similar to this this summer. I taught a camp of twenty six 11 to 15 year olds how to make piston valve cannons. Took a little over a week but was well worth it.

Wa kao.......I haven't mastered the art of piston cannons myself. My latest piston cannon can't seal properly..... And as far as I know nobody in Singapore has ever built a working piston cannon yet or anything beyond simple chamber-ballvalve-barrel guns. Wa kao........I am the blind leading the blind indeed.

Spudgunning is not an end in itself in my science club. I use it as a means to teach people stuff, mainly safety - as the danger is clear, obvious and easily spotted. What is taught to everybody is the very basics - how not to kill yourself, a bit of basic construction and so on. If they are interested and wish to continue further, I can and do help them as much as possible, though the extent I can do so is very limited.

Attention span is one factor, but a lot of the things are hands on, so they take notice. After they see the youtube videos, they start to take stuff more seriously.

As for gun safety, I wish I was able to teach it more in the open, but this is Singapore and the norms here are different from that in the West. The killjoy mentality is somewhat prevalent here - any sign of danger and the thing gets banned. Airsoft, for example.

Yes, although the strict law works and keeps our streets safe, on the other hand we spudders can also get into trouble because of it. That is the main reason why I store the guns like a military armoury - to prevent them from getting into the wrong hands, which could easily get us into trouble.

[limbeh]

perhaps you should take some dry ice and water, put it in a soda bottle, and seal it, and throw it far away from you and see what happens. These bottles don't simply rip open slighty and leak out air, they explode.

Thanks. We don't have much secure areas to conduct destructive testing of bottles, so we didn't really know that much about it. I'll probably change the basic design to PVC, it shouldn't add much to my costs.

As has been raised by a number of people, I would like to clarify that "preventing hardcore people" means to restrict possible destructive mischief that could be done using spudguns & other dangerous stuff, not enthusiasm. Obviously, as a leader in my science club I want all the enthusiasm that I can get my paws on.......

Now, replying to some interesting comment by john bunsenburner using the same American tone that I learned from this site:

You are lucky to be on the other sie of the world because its hard to get me this angry and survive...

Wow. I'm quaking in my socks indeed (using the American sacarsm that I learned from this site), because that kid going by the name john bunsenburner is gonna beat me to death with a Chem Olympiad textbook.

your to ignorant to do so

i have pretty much every high explosive in my cellar, i know the periodic table by eart, i know what the teacher will say once he writes the days topic on the board. I am the youngest in my country to ever join the national chemistry olimpiad being under the 42 best chemists that are not on a university and under twenty.

OK, we know you are very smart, but can you please note that not everybody is as smart or fortunate to have the same opportunities to realise their interests and talents as you. Not everything in your society can be applied to mine.

Yes, we may not know much, but we are just starting out. I myself only learned about them 2.5 years back when I stumbled upon this site. Obviously, we want experienced people like Killjoy to help us out, but there aren't many such people in the region. We have to learn everything by scratch.

and ym age? I am 13 years old!

Good. Hope you grow up fast. With your arrogant attitude, narrow mindedness, and belligerent tone, I doubt it'll be long before you find yourself in a lot of trouble with other people.

[littlebro05]

I think it's a great idea!

In Australia, we can't build these projectiles so good on ya. Out of curiosity what kind of ammo are you planning to use? Maybe wet wadded toilet paper or something, I wouldn't use anything too solid.

I agree that's it's not too scientific, but I reckon you could apply some gas laws into this like Boyle's gas law. The only thing I'm worried about is the age group of 14-15. I'm abit worried that they might get out of control. Growing up till I was 17 this year, there were a lot of idiots. Btw are they taking their construction "home" with them. And I think you should maybe limit the pressure to 40PSI-50PSI because at those pressures it can still do some serious damage.

@john bunsenburner - I think you're being ignorant and arrogant don't you think, your 13 years of age and your in the "olympiad" BIG deal! It's not like your special or anything. Just because your smart that was a pretty immature thing to do, to flame about his idea and calling yourself hardcore. Hardcore? Not really. And I know because people in my school who are considered as nerds and are arrogant at the same time are usually the ones who get bullied.

You could of simply said "no I don't like this idea' add a little reason. If you continue this ignorance there will be a lot of people who will not like you in real life. I think you should apologize for this because getting angry over something so trivial is really making us "spudders" look *unprofessional* as you might say it. I dunno any other way to explain it.

[Ragnarok]

I'm going to poke my head in here.

I don't necessarily agree with limbeh's application of teaching people to make cheap and easy launchers without very careful regard to who is getting the information.

I don't however think he's done anything to deserve the assault he's getting.

~~~~~

As an aside to John Bunsenburner, boasts of one's intelligence or skill don't normally go down too well on a forum. I speak from experience on that one.

I know I do things like that to a lesser extent - for example, I will remind people that I am doing a degree in engineering when it's appropriate or important, but I don't spend my time reeling off stuff like the fact that I have an IQ within the top fraction of the top percent, hold a world record, have been published, can stick my tongue up my nose, prefer to shower in pitch darkness, am a certified Lord of Karma, or other crap like that.

People don't like being told they're not as good as you, and telling people how good you are, especially if you're doing it to try and prove a point has an automatic tendency to do that.

[limbeh]

Ah.... finally Ragnarok comes. Was waiting for him to comment on the gun.

Ammo for the guns - toilet paper soaked in water. Used AA Batteries if we intend to do damage shots, but then and again we don't destroy things, we salvage them. However, should any damage videos appear, obviously I would be using batteries (try penetrating your target with wadded soaked toilet paper lol)

I agree with Ragnarok that it's a hard to restrict information from troublemakers though, but then this is our method:

Usually, we teach this as part of the basic training that new members get. Initially, we just show the exploding cannons at the start to remind them about the dangers, the details of actually building the gun come near the end of the basic training (a few months). During these few months, people would learn everything else first and then after they learn the basics of plumbing they go clean some old woman's clogged sink before we teach them how to abuse plumbing for spudding.

This weeds out the more undesirable elements - people who are only interested in destroying things and not in science (we don't mind people with both, provided they can limit their urges to destroy to the right time).

Tight security is something that Singapore is very good at, and we also follow their practices. Kids using their weapons or building weapons must surrender their handphone, & ezlink card (which you need to take public transport here) IC (equivalent to driver's license, money cellphone) and they are supervised by those experienced in building spudguns. Even if they somehow escape with the gun, they won't be able to go very far before we get them. Obviously, they can't take their spudguns home with them either.

I don't mind being insulted by John Bunsenburner, just that my science club spudders helping with the teaching program had a lot of fun laughing over what he said - the much vaunted Chemistry Olympiad which he derives his sense of identity from, we have people taking multiple olympiads lol.......

[maggotman]

^I agree

I think if you want to make a cheep gun make it out of use one size of pipe im not sure what pipe is avalabul but i think something that would fit paint balls would be good. i would use a small chamber to keep power down and reduce the filling time witch nobody likes like a 50cm barrel and a 20cm chamber with a simple ball valve

if you are evolving other people i would not use a bottle as a chamber.if it blows on you its bad but if it goes bang on one of your mates im sure you would feel a bit crap about it.

[limbeh]

I think if you want to make a cheep gun make it out of use one size of pipe im not sure what pipe is avalabul but i think something that would fit paint balls would be good. i would use a small chamber to keep power down and reduce the filling time witch nobody likes like a 50cm barrel and a 20cm chamber with a simple ball valve

Paint balls......mass producible paintball guns are another project we're currently designing. Massive chamber for multiple shots, QEV and regulator. But then and again that's more of a BBMG thing than pneumatics, so not here.

True. The lousy C:B ratio is due to the size of the bottle lol. It's obviously not practical to run around carrying a 3m long barrel (even if you ignore the fact that the pipe will bend considerably) lol.......

[john bunsenburner]

I am not boasting, i wouldn't of posted any of this if not to prove a simple point: That preventing the harcore kids is simply the wrong way about it!

I doubt that making these "mass producable" guns is really very scientific at all, nor do i think it is safe that you use them with that age group seeing as how stupid things happen very quickly during the act of carelessness.

I didnt mean to flame you as bad as i did and i appologize for any hurt feelings but i was tryign to bring a point across.

Again i ask wether or not this club is volantrayry and if the children gain anything from attending it?
If the children gain nothing and it is just volantray then i think you are a little too baisic seeing as how, atleast in my school, things start getting a little more complex in that year's science classes. Also it would be intresting to know what kind of children you are dealing with here after all there is a difference between leading a club for average pupils and one for the more intelegent ones.
If you are dealing with the average the project is not all that bad, if with "problematic" kids of any kind i wouldn't deem this all that safe if you are dealing with mor intelegent or more complexly thinking children then i think you should try something more chalanging(perhaps, if you have a group of very bright and ambitious students trying to break the sound barrier, though alot of safety and resources would be required that is a great project).

Again i am sorry for any hurt feelings i was really just talking from experience, and i am not sure if you can imagin how horrible it feels when a teacher doesn't let you develop or learn. I have made even worse experiences with older students who where teaching one of these clubs as they often(i am not talking about you in specific, just over all) have no clue what they are doing and just want to earn some kind of credit.
These experiences can be really unconfortable for certain children and so you have to know with whom you are dealing with.

Please take my appologies as i did not mean to flame you as bad as i did but also please consider my points. And again there was no intension to boast it was really just an attempt to demonstrate that the kids that sometimes behave like "harcore" children are acctually the brightest ones. All i want to say is that each and every one of these children might or might not become soemthing great accademically speaking and that you have to give each of them a fair chance. Thank you.

Regards, John.