Pneumatic Pen-gun Project

[PVC Arsenal 17]

I wonder if you could have used just a bb as a piston. It would probably be lighter and should work just as well.

[iknowmy3tables]

DAMMIT I had this exact Idea, even the part about using the schrader to actuate, do you realize how annoying it is to have you idea taken to be used against you is a competion while his thread has multiple pages while mine only has 5 replies and has been out for longer

i have briefly mentioned it before,

100ft, mini, thats pretty good, I bet you could make a coaxle, and using a rubber schrader as an refill, actuator, even a bumper for pistons

http://www.spudfiles.com/forums/a-mini- ... rt,15.html

and I even have a prototype in the shop for the schrader concept



yeah it a piece of crap because I don't have access to a hardware store execpt this crappy local one that doesn't even have brushings (which is why deus ex machina is all streamlined exept for the large chamber which is scrap), I've had it forever, but I couldn't find a new diaphragm, the last one was made from tire patches but it it got sucked in the barrel somewhere past 40psi I still haven't found a working diaphram

[Hotwired]

Tsk tsk... gotta move fast after showing your ideas otherwise someone else will reinvent them and you'll lose the credit

[clide]

Making a small coaxial triggered by a schrader is nothing new, thats what pretty much all of jack's minis are, and I've even seen it on guns before jack's.

This gun is impressive just because it is so darn small.

[origin unknown]

This gun would be a great way for self defence for like an old person or a woman. They could just carry it in their pocket or purse, just in case a criminal happens to attack. It probably wouldn't severely wound the attacker, but it would give them good wakeup call not to come any closer. A stun gun would be more reliable and safe though.

[jackssmirkingrevenge]

I wonder if you could have used just a bb as a piston. It would probably be lighter and should work just as well.

I considered this option, but since once the parts are epoxied in place, they're fixed for good and I can't access the internals, I though i'd better play it safe and use a conventional piston.

DAMMIT I had this exact Idea, even the part about using the schrader to actuate, do you realize how annoying it is to have you idea taken to be used against you is a competion while his thread has multiple pages while mine only has 5 replies and has been out for longer Evil or Very Mad

No need to bunch up your undies, I've been making mini-coaxials like this for years now, nothing new under the sun

This gun would be a great way for self defence for like an old person or a woman. They could just carry it in their pocket or purse, just in case a criminal happens to attack. It probably wouldn't severely wound the attacker, but it would give them good wakeup call not to come any closer. A stun gun would be more reliable and safe though.

I'd rather they carried one of these, for their sake:

[thrasmussen]

Is your shrader valve modified or does it come that way. Without wrench lugs.

[jackssmirkingrevenge]

The schrader is taken from a bicycle inner tube. I first strip off the rubber to reveal the brass body, this is what it looks like half way through:



Then, depending on the project requirements - as short as possible in this case - I cut it down with a hacksaw. There is a minimum length of course, you have to leave at least the equivalvent length of the threaded portion otherwise you'll cut through the internal mechanism.

[Los Frijoles]

This gun is so insanely cool . I am now seriously inspired to make something like this...

[jackssmirkingrevenge]

Thanks It's really not that hard, you just have to be a little patient with working with messy epoxy and small components.

I added some marine epoxy reinforcement to the leaky area, so expect some 400 psi+ tests some time tomorrow afternoon

[Hotwired]

Is the barrel wide enough to allow a cheap non-sprung ball point pen cartridge in? They're a couple of mm in diameter including the brass ball nib.

I've used them before on a 3.5mm bore barrel with the end split and flared to fill out the bore and they make lethal darts.

Fire them fast enough and the plastic tube of ink behind the brass nib splinters into inky shards from the impact... after burying the nib up to an inch into green wood or softwood.

In this case I think they could be perfect, particularly as it's disguised as a pen.

[jackssmirkingrevenge]

brilliant idea, sadly only the nib fits I tried shooting a headless nail at a CD clamped in a vice and it blew it in half, so I think some further investigation of more substantial projectiles is in order. Not just yet though, got an FT competition tomorrow morning so I'm dedicating my time to my beloved Daystate for now

[thrasmussen]

Now you said machining. What machining?

[jackssmirkingrevenge]

Now you said machining. What machining?

I did? No machining involved whatsoever, simpling cutting tubes to size. I used my improvised lathe simply to be able to clean up the ends of the tubes with a file and sandpaper.

[thrasmussen]

That's good. I don't like to much machining