My version of Keychain Pen gun

[CpTn_lAw]

You could have soldered the shrader valve in place, you could have unscrewed the midle part, solder the body to the gun, screw the middle part back in...

Very nice mini

[john bunsenburner]

The middle is called the core...But yeat that works well

[jor2daje]

Actually that wouldnt have worked because theres still a plastic piston with a rubber sealing face that would have melted if I had soldered the schrader without a core.

[THUNDERLORD]

That looks top notch!
Why not fill it with a tyre filler 8, 12 or 16 gram co2 cart?

My first thought was same as JSR and others (cigarette shooter).
I read somewhere a shrader can loose about 3 psi per month on car tires.
Mostly from hitting bumps or turning against curbs...car tires loose psi through shraders somehow though...seems more so during cold weather(?).
Awesome pengun there, (hadn't noticed this post before)!!! 8)

[FORE!!!!]

Can i ask where you got your brass tubeing from??

Im now interested in replicating this device somewhat

[jor2daje]

I got if from Channel City lumber, but I've seen it at other hardware stores, and hobby stores.

[FORE!!!!]

Another thing getting your piston to hit back using a shrader valve, what are the main principles in aquiring this feat?
or should it just WORK! if the piston has a tight enuff fit?

o rings maybe?? i plan on using an expoxy cast piston without o-rings,would it still work??

[qwerty]

On my coaxail i can actuate it using the scrader its just down to the piston being tight enough.

[jor2daje]

Ya that should work fine, because the pilot volume is so small even a shrader can easily pilot, a relatively loose piston.

[jackssmirkingrevenge]

because the pilot volume is so small even a shrader can easily pilot, a relatively loose piston.

The key element is that the area of the space around the piston (ie, area of chamber inner diameter - area of piston outer diameter) should be less than the area through which air can flow out of the schrader. If the reverse is true, then the pilot volume will be filled up by the main chamber volume faster than it can be emptied through the schrader and the piston will never actuate.