How to build a pneumatic air cannon

Well I live in Ireland, and as everyone who lives here knows that getting materials is a complete bollocks, but anyway, i spent about 3 months looking for a way i could build a pneumatic air cannon without high pressure piping, then one day whilst browsing the net i stumbled upon a gold nugget.. fire extinguishers, theyre pressure rated, so i set about looking for a fire extinguiser and a fter a short period of time i got one free of charge as it was empty.

Shops needed.
1: a diy plumbers supplier, as in anyone can buy stuff there
2: a diy shop, i went to homebase
3: anywhere that sells fire extinguisers

Tools needed .
1: a pipe wrench
2: a table mounted vice
3: your hands

Other needs.
1: steel epoxy, i used loctite, withstands up to 130kg per cm2


ill post the rest later i have to get off the comp

rite get the fire extinguisher (empty it first) then secure it horizontillay with the vice, then get the pipe wrench and screw off the valve on the extinguisher. the go to a plumbers and search for a reducer that will fit into the threads of the extinguisher. the buy a nipple that will fit into the extinguisher, the a tee fitting that will fit onto the nipple, then 2 nipples to go into the tee fitting.
shite i have to go again

OK for those of you in ireland,use the standard pluming pipe(the black stuff)for spud guns.once you go over 50mm its pressure rated for easily enough 250ish psi.i was in america over the summer and brought me back 4 solinoid valves way hey!

Cool youre irish?Look at TheFallenAngles guide

[TheFallen]

Uhm, my guides aimed at Combustion Guns. But cmhdwwi's recomendation to use normal pipe is a bit dumb. When I say a bit dumb I mean bordering on the realms of Darwinian Award stupidity.

Normal plumbing pipe is for water, and thus does not have all that great pressures acting on it. It is generally un-rated, therefore unsutable for any kind of medium pressure system, let alone a high pressure system.

ouiskipoiski's idea with the Fire extiguishers is excelent, but be aware, all joints should be fixed with PTFE tape. Oh and another propblem, all threads assosiated with High pressure componants will invariably be NPT. This is a conical thread which is complex to homemake ...

cmhdwwi, What do you mean by 50mm pipe, as far as I know there is no such thing. The standard sizes are 22mm, 32mm and 40mm. There are some much larger pipes at 100+mm but they're generally used for drainage/sewage uaseage, and thus are worth even less.

I myself have a good resourse of bits, [link=http://www.rswww.com]RS[/link]. They stock Everything, and I truely mean that. They a re used by comercial companies like Thales and others. Only down side is that they are a bit pricy, okay, bloody pricy, but they have it all !

But of course from that you may think I'm ahaingst it, but no, I'm hoping you do succsed. [link=http://www.geocities.com/spudguns_uk/1_5_abs_pneumatic.htm]This[/link] bloke did.

But a Fire Extinguisher, inspired that is.

[DeAd]

hey i made something like this all out of cpvc its really kinda cool for a toy. I think its way better than the one in the geocities link above. It probably cost about $20 altogether. One thing i learned is that volume of air is just as important as pressure. made it breach loading with a pressure gage from a fire extinguisher. It can be pumped up with bike tire air pump or air compressor. 50 psi will send a sabot with 30 paintballs 100 yards and break the paintballs.
http://i207.photobucket.com/albums/b...o/100_1517.jpg
http://i207.photobucket.com/albums/b...o/100_1516.jpg