SpudFiles

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

- 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.

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

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

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.

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)

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.

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

joannaardway wrote: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.

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.