SpudFiles

i want to build a co2 powered pnumatic gun. i can't figure out if i should use galvanised or abs. and also what would be the best size of the compression chamber?

you sure as hell shouldnt use ABS, it'll explode on you. i hope you know that co2 is at 800 psi, and if you put it in anything without regging down the pressure you're likely to kill yourself. galvanized leaks like a bastard at higher pressures unless you get some thread sealant too. you shouldnt be messing with co2 if you dont even know not to use ABS in a pneumatic

Ahh, but solid core ABS is pressure rated, albeit it's very rare. Of course, even with solid core it needs a reg.'
A good choice would be copper. It's cheaper and it holds a lot of pressure.

yeah, though the copper might still burst since the co2 is extremely cold, so you need to reg it down no matter what you're using

i know how much psi is in co2 i paintball. anyway i was only going to use a 12 gram with one of those adapters.

oh, well thats different then, just look at BC's co2 volume chart so you can figure out how big your chamber needs to be

where is BC's co2 volume chart? and should i use metal or abs

it's at the top of the general topics, and unless your ABS is solid core, and pressure rated use metal instead, you CANNOT use cellular core abs in a pneumatic cannon

http://www.geocities.com/cain333_2000/caddy.html The mad caddy is a VERY cool gun that runs on 12 grams, you might make a clone of that.

yeah, but use an NSF-PW reducer instead of the DWV bell reducer he used

What is the difference between the two, and why is one better?

DWV is generally not suited for pressure because of short sockets for bonding. It can be used but isnt geenerally reccomended.

are you guys talking about the brass thing that goes from the 12 gram adapter to the chamber? and also on the mad caddy is the chamber made of sleved pipe or a large diameter pipe?

i'm talking about the reducer bushing that he used to go from the 3" of the chamber to the 1" of the valve, that reducer is not pressure rated, if you cant find pressure rated fittings near you (they say NSF-PW on them) go to http://www.plumbingsupply.com http://www.mcmaster.com http://www.savko.com or http://www.usplastics.com for them the chamber is not sleeved pipe, its just 3" pipe, you wouldnt want to sleeve a chamber anyway, since cutting pipe to put inside of it would probably give extra stress on the inner cut pipe

on the mad caddy it says "the chamber is 3" pipe completely encased by the three fittings" what does that mean. and also it looks like it is using pvc isn't that dangerous?