What brand and model?
Pictures?

What thread is your 3/4 pipe? NPT. BSPT, BSPP

If you have caliper, measure ID of extinquisher thread.

Here is example of extinquisher as chamber.
http://www.spudfiles.com/forums/viewtopic,p,236916.html#236916


Note internal construction:

Yeah mine has that tube ...

hey i have a fairly new fire extinguisher that would be a great air tank for a current project but how can i make an air tight seal in connecting it to standard piping? when i screw in 3/4 inch galvanized piping it only goes an 1/8 th of an inch deep before getting stuck and askew. im sure this has ...

That littlebit of blowby could be huge in comparison.
How big is the barrel?
If that takes up a large portion of the sealing face and you have blowby...

well.....
there's your problem..

If you are able to machine the pistons, why not add a floating O-ring that works like a checkvalve..

what do ...

i have a tattoo on my right hand. i got it when i was 8 from a bad cut that i colored in with a fountain pen every day

streetfire wrote:maybe the air isn't getting past the piston so there is nothing to fire make a small cut in the piston to let air through

its under size, the tube inner diameter is .478 and my piston is .465

I have been trying to make a few mini co-axial piston valve guns and have not been succeeding very much. the problem i keep having is that the piston will seal but it wont pilot? i am using a schrader valve to fill and pilot and my pistons have all been machined nylon with rubber sealing faces. what ...

i mean the ones that JSR recommends for semi-auto

wyz reported leaks at higher (300 ps) pressures. You can get 3000 psi rated paintball slide valves though.

would this work?
http://www.ebay.com/itm/1-8-NPT-Compact-SLIDE-CHECK-CO2-Gas-HPA-Air-Remote-Hose-Bleed-Valve-New-FS-/120871439580?pt=LH ...

Crna Legija wrote:

urgle the danish cow wrote:does any one know what pressures a slide valve can take?

what kind if its a paint ball it would be fine for 1000 psi with out a problem

i mean the ones that JSR recommends for semi-auto

does any one know what pressures a slide valve can take?

[quote}Hmmm... to be honest I've only tried it to 150 psi or so, so I can't comment about high pressures. I will try and compare construction to the 3000 psi rated slide valves I also have.
[/quote]
let me know when you test it out

its my understanding that the qev uses 1/4 pipe threads. will that restricts flow too much?

quick question pour vous tout. im working on a design for a bolt action .50 cal and it will use a QEV and a slide vlave. my air chamber will be turned on a lathe and steel, about 1 inch. probably operating at high pressure (hopefully 400-500 if i can get a fridgy) jsr has linked for us in the past ...

very nice!
for mine i like to turn on the mitsubishi water jet and cut them out of 1/4 inch aluminum. they make nice whirring noises and fly like hell.

alright well for one of my projects i know that that will work. but the other one i was planning on milling the dovetails right onto the think steel air chamber. to do this with the pre made rails would i drill and tap holes for the rails bolts to screw into the air chamber. what would be the best ...

so 11mm wide will fit a scope? and you seemed to imply that there was a better way of mounting a sight. is there?