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My version of Keychain Pen gun

Unread postPosted: Sat Jul 04, 2009 4:06 am
Author: jor2daje
I saw Jook's keychian gun and decided I needed one too. I had pipe left over from my brass pen gun so I decided to build it out of that. Its nothing to special 2.5" long about 8mm wide with a 3mm barrel. I built another firing cap similar to the one on my larger pen gun.

Shortly after building it I looked at another pen gun and saw this that JSR posted and decided to try my hand at building a small pump. It was surprisingly easy about an hour at the drill press and I had a floating oring piston that works great in my 8mm brass tubing. Im not sure exactly what pressure it can achieve but same gun firing same ammo penetrates much more using my pump as apose to a bike pump.

I normally fill the gun with about ten pumps from my small pumps, after that the power increase isnt significant enough to warrant more effort.

No damage pics right now but I got a nail to go through both sides of a coke can.

Unread postPosted: Sat Jul 04, 2009 4:12 am
Author: inonickname
Nice! I never really got the hang of building penguns reliably..

How about a keychain/keyring epoxied to it? A good source is cheap rubber keychain additions sold for charity. You help sick people, and get a keychain!

Good job, what's the stroke of the pump? With info like that we could give rough estimates of pressure.

Unread postPosted: Sat Jul 04, 2009 10:17 am
Author: Technician1002
Very nice.. Well done. Looks like something 007 would carry.
:wav:

Unread postPosted: Sat Jul 04, 2009 12:21 pm
Author: twizi
very well done
btw you should make ahow to on the pump

Unread postPosted: Sat Jul 04, 2009 1:00 pm
Author: qwerty
what did you use to seal the barrel on the chamber ,epoxy putty?

Unread postPosted: Sat Jul 04, 2009 8:58 pm
Author: jor2daje
Everything except for the schrader is soldered together, I epoxied the schrader becuase I would have melted the piston if i tried to solder it.

Unread postPosted: Sat Jul 04, 2009 9:14 pm
Author: theBOOM
How hard was it to build the shock pump? :?:

Unread postPosted: Sun Jul 05, 2009 4:56 am
Author: jackssmirkingrevenge
very nice, a lick of paint and you have yourself a "cigarette gun" :)

good work on the pump too, been wanting to build one myself, though now I have the option of 800 psi fills from my paintball tank. I don't think I'd trust a schrader past that pressure anyway.

Unread postPosted: Sun Jul 05, 2009 1:57 pm
Author: MountainousDew
Good job mate! (I'm unfortunately not Australian)

Do you think you could take a picture from the barrel side(at the barrel)?

Unread postPosted: Sun Jul 05, 2009 2:06 pm
Author: jook13
I love this! looks much nicer than my keychain gun. Great work on the pump as well. I made a pump that worked, but too well. I had the issue of getting past the crack pressure of my schrader, so it didnt fill very fast. I like my shock pump anyways.

I have the option of 800 psi fills from my paintball tank. I don't think I'd trust a schrader past that pressure anyway.


I remember gipetto testing a schrader up to 10,000 psi and it showed no signs of letting up. I would worry about the epoxy more than anything at those pressures.

Unread postPosted: Mon Jul 06, 2009 1:15 pm
Author: jackssmirkingrevenge
jook13 wrote:I remember gipetto testing a schrader up to 10,000 psi and it showed no signs of letting up. I would worry about the epoxy more than anything at those pressures.


I seem to have missed this particular snippet of info :shock: well technically I have a maximum of 4,500 psi available in my SCUBA tank :D

I wouldn't worry about epoxy as long as there's enough of it. Remember, even air is technically "bulletproof armor" if you put enough of it between you and the bullet ;)

Back to the subjecto f this thread, seriously it's begging to be painted half white, half brick orange ;)

Unread postPosted: Mon Jul 06, 2009 1:53 pm
Author: Gippeto
Setting the record straight, the valve core of the schrader (the sealing face to be specific) was destroyed by the 10000psi test. However, it did not leak.

Replacing the valve core brought it back to "good as new".

Gotta go with Jack on this one. It does look like some sort of James Bond'ish cigarette assassin weapon. 8)

Unread postPosted: Mon Jul 06, 2009 1:55 pm
Author: spudtyrrant
shoot it with your tongue lol

Unread postPosted: Sat Aug 15, 2009 1:41 am
Author: theBOOM
Maybe a little how to on the mini pump?
And btw nice gun, has it been painted yet ? Any damage pics or videos anytime soon?

Unread postPosted: Sat Aug 15, 2009 2:45 am
Author: john bunsenburner
I don't see why two people need to ask for how to's if there is already one (that is very good) on pumps, and the pump above is so darn simple you should be able to build it from having a few looks at the pics.

Otherwise I ditto on the cigarret look and recomend some one makes a ciggar gun some time soon.
Could you give us a rough estimate of pressure and maybe even a video of a shot seeing as how performance is hard to estimate on minis, though really performance isn't the main goal, or achievement in one.

Anyway good job, very clean and simple build, one of the nicer penguns up here.

Oh and by the way, shrader valves are fairly big in mini's there needs to be a smaller solution found for smaller minis, and for small minis with larger chambers and barrels. A shrader core would solve the problem(you screw it into a small, threaded hole in the back of the gun), but i can't think of much else.