fire extinguisher chamber on a pneumatic

[Petrie]

I am building my first pneumatic and i want to uses a fire extinguisher (300 PSI) as the chamber but i have a few questions. Any insight would be much appricated.

-Would a FE chamber be wise for a first timer?

- Are the FE threads compatable with pvc?... Brass?(If i use brass can the pvc barrell and sprinkler valve be attached?)

- How would i go about attaching a filling valve to the Extinguisher?(I cant really use the push in schrader valves)

I am also very open to using pvc for the chamber i just have an empty FE on my hands

Thanks

~petrie

[sergeantspud2]

- Yeah why not use a fire extingusher for a chamber they look sweet on cannons, But as a first cannon Im not so sure. If you know the basics of a pnumatic then yeah, but with these questions I think you need to start with a less complex cannon just the sharpen you skills.

- As for the threads on the tank Im not so sure on. But being able to mix brass and pvc is okay because they are all NPT threads.

-After the tank and before the valve put a T and a quick connect (for air compressor) or just a schrader valve.

[SpudStuff]

The threads on there are either NPT, NHT, or BST.
That is american threads, hose threads, or british standard thread.

[frankrede]

Mine used hose type threads, but mine was a dry chimcal one at low pressure.

[joannaardway]

The threads on a CO2 Fire-Ex are a nightmare in the UK - or so Ragnarok tells me. They're close to, but don't quite match 1/2" BSP.

So, his latest idea is tapping the inside of the brass bit with a 1/4" BSP thread, which sounds like it could work.

If it's a tank that has a gauge, or safety valve, unbolt that, and attach your fill valve to that hole somehow.
The UK CO2 ones have what is almost a 1/4" BSP thread for the safety valve - if it leaks a little, use a blowtorch and some solder - use that to plug the gaps, a la an endfeed fitting.

[Petrie]

is there anything special i need to do when screwing in a 1/8'' schrader into the thin allumanum wall of the FE.

(my FE is a dry chemical one)

[sergeantspud2]

If you wanted to screw it directly into the FE you might need to tap the hole. Or if you can find a drill bit close enough to the size of the schrader threads just have it make its own threads.

[SpudStuff]

The walls on the tank aren't thick enough to tap into. You need to use a Tee fitting after the chamber.

[MrCrowley]

The threads on a CO2 Fire-Ex are a nightmare in the UK - or so Ragnarok tells me. They're close to, but don't quite match 1/2" BSP.

So, his latest idea is tapping the inside of the brass bit with a 1/4" BSP thread, which sounds like it could work.

If it's a tank that has a gauge, or safety valve, unbolt that, and attach your fill valve to that hole somehow.
The UK CO2 ones have what is almost a 1/4" BSP thread for the safety valve - if it leaks a little, use a blowtorch and some solder - use that to plug the gaps, a la an endfeed fitting.

Ragnarok is correct the threads are between 1/2" and 3/4",what i did is i got this white plastic thing from the inside of the FE,it was part of a tube that sucks up the powder and i cut the threads of the trigger and......somehow it worked and the white thing had like 3/8"threads to 1/4" threads ill post pictures soon. as for the plug in schrader i managed to use one,i made a hole got some pliers and pushed them into the hole to make it slightly bigger then i put a HUGE drill bit on the bottom on the schrader and put it through the neck hole and banged the drill bit on the table and it pushed the schrader through.

[Infernal2]

Well, I used a dremel to sand down the threads on the output connection. After sanding I was able to lightly hammer in a 1/2 piece of copper pipe which I then soldered in place. On the other end of the copper pipe I attached a 1/2 NPT copper female adapter and voila! Simple chamber.