tiny pen gun... with videos....

[jook13]

So its pretty much a copy of JSR's pen gun, but about an inch shorter. Another difference is my piston has the sealing face on it, versus his with the sealing face on the barrel. As you can see in the videos, it went through 3 beer cans lined up (empty) so I am pretty impressed. The ammo of choice is shot from a shotgun shell...

The chamber is 1/4 inch brass tubing. the barrel is also brass tubing that measures just under 1/8 inch outer diameter... The piston is a small epoxy cast. actuater by the schrader of course... I also like the idea of making a trigger out of a pen cap, since a pen cap fits perfectly on this thing...

Sorry about not having pictures of the internals, its all epoxied together.

The videos both are shot at around 350 psi:
http://smg.photobucket.com/albums/v13/j ... CF0076.flv
http://smg.photobucket.com/albums/v13/j ... CF0078.flv

new easier to see video....
http://smg.photobucket.com/albums/v13/j ... =Movie.flv

[cannon monkey]

how does it work?
i never seen any thing like that before

[rp181]

your should consider making a epoxy cone at the end that sloped toward the barrel, and paint it black =)

[littlebro05]

Cooolll, through 3 cans.

Hmm you filmed it in like a dark place, didn't know what was going on lol.

[cannon monkey]

how did u make it and how does it work?

[MrCrowley]

how did u make it and how does it work?

It's a coaxial piston valve. He made it like any other co-ax, just on a smaller scale.

[CasinoVanart]

Very cool dude, JSR will be so proud!!

[Mr.Sandman]

Those penguns are really hard to make....... on second thought maybe i just suck at building co-axials. you know ive never made a working coaxial.

[jook13]

shoot. sorry about the videos. It looked fine, but then photobucket made it darker when it was compressed. I'll get a better vid of it.

your should consider making a epoxy cone at the end that sloped toward the barrel, and paint it black =)

that would be sweet. but I love the look of the brass. now if the had brass colored epoxy....

how does it work?
i never seen any thing like that before

read this link : http://www.spudfiles.com/forums/piston- ... t8157.html

Very cool dude, JSR will be so proud!!

Thanks buddy.

Those penguns are really hard to make....... on second thought maybe i just suck at building co-axials. you know ive never made a working coaxial.

Keep trying man... one time it will work for you and things will just click inside your brain

[Eddbot]

Nice job, i agree with rp181, it would look pretty inconspicuous with a tapered end

btw what's the song playing in the background of the first vid?

[Dgealy]

Did you modify the schrader valve to fit, or were you able to find/buy one? If so, where might I look for a smaller, specialized brass one like this?

Also, did you epoxy in the schrader valve, or did you somehow thread the outer chamber?

Last: Can you fit a normal pen tip from one of those pens into the barrel, including the whole plastic ink tube?

Looks amazing.

[jook13]

Here is a link to a much easier to see video.... I didnt realize how dark the others were till After the post.
http://smg.photobucket.com/albums/v13/j ... =Movie.flv
I added the video to the original post as well

Nice job, i agree with rp181, it would look pretty inconspicuous with a tapered end

btw what's the song playing in the background of the first vid?

I agree it would look sweet tapered, but I love the brass... maybe if the taper was black and the rest was brass? And that fist video had the song Barracuda by heart... my friend was playing Guitar Hero 3.

Did you modify the schrader valve to fit, or were you able to find/buy one? If so, where might I look for a smaller, specialized brass one like this?

Also, did you epoxy in the schrader valve, or did you somehow thread the outer chamber?

Last: Can you fit a normal pen tip from one of those pens into the barrel, including the whole plastic ink tube?

Looks amazing.

The schrader was from a bike inner tube. I just stripped away all the rubber from around it and was left with a small nub on the other end of the schrader that fit into the tube... from there it was epoxied in.

And no, the ink tube wont fit in the barrel, my barrel is actually way too small for that.

also... thanks!

[jackssmirkingrevenge]

Very cool dude, JSR will be so proud!!

He is, nice one!

Seems more powerful than mine too, it's crap with shot as ammo. On the other hand, due to sealing problems I never managed to take it to really high pressure levels.

[jook13]

earlier today I used my fridge compressor and maxed out the psi... I am not sure what psi it was, but my 300 psi guage was pegged for a few seconds... I am guessing 700 psi? the gun held up fine.

the main issue is mine wont seal until around 150 psi or so...

I was thinking of making a mini pump from some brass tube the same size as the chamber, just to have it match and be a cool little set. anyone try to make a pump on this scale?

[jackssmirkingrevenge]

I know I keep saying this but I'm either going to get my hands on one of those fridge compressors, or make a schrader adapter for my SCUBA tank. I'm sure the construction can take at least 1,000 psi assuming good use of quality epoxy.

A mini-pump would not only be cool but also give you the opportunity to reach higher pressures, for example at 1,000 psi assuming a 6mm tube the force you need to apply is 43 lbs, which is equivalent to the force you need to apply to a typical bicycle pump to get it to to around 25 psi.