SpudFiles

sparktech wrote:jakethebeast, you said its fairly dangerous with unregulated co2, what if i used this

As I said before, I have filled pen guns w¡th unregged CO₂ as well as HPA at 850 psi without incident, as long as it's well made with suitable adhesive you have nothing to worry about.

The adapter you linked to is made for airsoft weaponry, if your pengun has a schrader fill valve/pilot it will not be suitable. Something like this is much cheaper and connects directly to the schrader.

I've put my paintball tank strait to epoxy( putty and adrility) and they survived. For the fill valve try a presta valve, cayse they are threaded and will hold well. They make make good triggers

well thanks you all of your guys' help i have finished my mini pneumatic pen gun!! i have yet to test it with a projectile though..i will do that tomorrow [/img]

could the rubber piston be replaced by a machined piece of nylon? or at least with small piece of rubber attached to the front?

Yes, but if the barrel is perfectly square-cut, then you don't even need to use rubber with some plastics.

When I first thoght of making this one thing had me in doubt.
The support that keeps the barrel centred at the breech would not work because the washer that centres the barrel has to be touching the air cylinder wall.
So I figured out a way around this problem. I decided to take a hacksaw and cut diagonal notches around the outside of the barrel (kind of like rifling but on the outside) and then apply a thinly cut tape over the barrels diagonally cut notches.

(note that this hasn't been tested as it is drying)

qyuubi786 wrote:The support that keeps the barrel centred at the breech would not work because the washer that centres the barrel has to be touching the air cylinder wall.

I direct the right honourable gentleman to point 3

It didn't quiet work out
It must be the hot glue gun piston that's leaking air.
Any ideas on what else to use as the piston guys?

Use thin rubber from those door bumbers, and a peice of plastic as the piston, wrap in tape if needed

Ok I will check if it works first thing tomorow morning

A solid rubber piston is a simple and durable solution.



Just a piece of thick rubber cut using a sharpened section of chamber tubing:

What kind of rubber?
I have 3mm neoprene will this work?

As long as you keep the distance between the rear of the piston and end of the schrader small (say 1mm) it should be ok. What's the inner diameter of your chamber?

It's 9mm's. Can I glue two or three layers of neoprene together as the distance between the piston and the schrader valve can be 1mm?

I would use only one layer, glued rubber parts tend to fail. Make sure that the total distance between schrader end and barrel end is 4mm, so the 3mm piston has 1mm of free movement.