need help w/ airgun valve mod

[ThudThumper]

i'm modding a pellet rifle to accept a constant air source from a 12oz CO2 tank instead of the default 12g disposables.  i've drilled and tapped threads into the valve and end cap and run a grease gun hose from my tank adapter to the end cap.  now all i have to do is bridge the 3" gap between the valve and the end cap.

i was originally going to tap threads on a section of brass tubing and screw in between the two, but i'm no machinist and my holes don't line up perfectly..so no go.  i can't find any steel braided hoses that are 3", so that's no good either.  i don't think i have a tubing bender small enough for 1/8" pipe.  is there a material soft enough for me to work with that can withstand 850psi?  i'm not familiar witht the burst pressure of copper pipe and such.

btw, i only need to make a very slight bend to make the two line up properly.[/img]

[Nobade]

You might see if there are any hydraulic shops near you and show them the problem. They should be able to make up a hose for you. I wouldn't use copper tubing, it'd be ugly to have it blow up in your hand. Also remember you want to keep the diameter as big as possible so as to not restrict the flow of gas.

[gunnut69]

I am really unfamiliar with airgun tech but I'd look at the local car parts store. They handle double flaired steel brake line tuning. That stuff handles a heck of a lot of pressure when dealing with boosted brakes..

[PeterF.]

A lot of guys go to "bulk fill" from the little CO2 cartiridges.  I don't know what brand you're trying to convert, but check with MAC1 airguns (www.mac1airgun.com); they mostly work on Crosmans, but they may have a "standard" part that solves your problem.  A Google search on "airgun bulk fill" will pop up a few other possibile sources.  HTH. Peter F.

[DMPelton]

I am an airgun tech for many paintball guns, and we use a flexible hose in some applications (it is rated for the 850 psi you are looking for) and you can cut it to the desired length.  I generally prefer the use of steel braided lines at pressures over 500 psi, and unless you are regulating that co2 tank you will be most likely operating at pressures over 850 psi, most co2 tanks (depending on the ambient air temperature) run between 1200-1500 psi (65-85 degrees fahrenheit.)  Those are rough guesstimates, as i've never scientifically tested co2 output, but i know this from the velocity changes in paintball guns as the days warm up.

You should be able to pick up the hose at a local paintball store, along with 2 quick disconnects ( they are like compression fittings) for either end of your connections.  

Also, when cutting the hose, use a razor blade as opposed to another form of cutting tool, as this will give you a clean edge and reduce the likelihood of leaks.

[ThudThumper]

thx, guys.  i finally just decided to bypass the whole problem and use an 18" grease gun hose from the local hardware store to run straight to the valve from the asa adapter.  no leaks to date, and it works great!  thanks for all the ideas.