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Posted: Sat Mar 29, 2008 6:14 pm
by fireman565
@Scottcrete
got these two 9 ounce tanks.. and am looking for inspiration on what to use them for.. any ideas? how much will they power a pneumatic? what do you think i should build that these will work nice with.. or are they just to small and would be a waste of time?

Let me know your thoughts.
Send them to me.. :D If you could find the female counterparts to the tanks, I would say you could do anything you wanted to with them, and then if you got tired of whatever design, you could re-use them, again and again.

Posted: Sat Mar 29, 2008 6:19 pm
by Velocity
POLAND_SPUD wrote:@DYI vast majority of people on this site have never used more than 300 psi.. so 35 bar is high pressure for most people on this site... kinetic energy isn't everything you know
I got scared when I filled my copper pneumatic to 125 PSI; the largest diameter fitting on the launcher is 1/2" :oops:

Posted: Sat Mar 29, 2008 6:27 pm
by scottcrete
i was looking at all the fittings at loews today.. and they are all rated for 125 psi.. so how is this compatible with the 1800psi.. or even 500 psi for that matters

Posted: Sat Mar 29, 2008 6:33 pm
by elitesniper
Copper fittings were only rated to 125?? :shock:

Posted: Sat Mar 29, 2008 6:35 pm
by fireman565
Somewhere in this world, they have to make fittings that match up to the bottle pressures. Possibly some paintball company? Brass Eagle? (Cough, cough... :wink: )

Posted: Sat Mar 29, 2008 6:38 pm
by DYI
The answer is, fittings at Lowes aren't compatible with 1 800 psi. AT ALL. I used 1/4" malleable iron fittings at 2 000 psi when I was testing my pressure washer for leaks(because the hydraulic supply was out of stock), but I was scared sh*tless while doing so, and I wouldn't recommend it, because you're getting dangerously close to the burst pressure of 3 000 or so.

I assumed that since you were doing welding, the fittings would be made out of plate with tapped holes, or pipes welded onto plates for male threads. These types of improvised fittings can be made ridiculously strong for almost no extra cost (like the 1.75" thick solid steel plate that forms the manifold for my hybrid's ignition and fueling). Lots of easily available fittings are rated for 3k or 6kpsi and available at McMaster, but plates with tapped threads are cheaper.

Standard malleable iron fittings (rated for 150 psi) are reasonably safe to use at 500 psi, and _Fnord has tested them to 11x hybrid mixes. The fittings are poorly made, but thicker than the pipe.

Posted: Sat Mar 29, 2008 7:41 pm
by POLAND_SPUD
so to sum it up - it is a better idea to use 400 psi because you can use easily available malleable iron fittings and still 400 psi is a lot of power... . if you you have never build a pneumatic gun before (or you have little experience with building them) it is a good idea to use malleable threaded fittings and steel pipes from the very begining - becasue every part that you buy can be used later

Posted: Sat Mar 29, 2008 8:30 pm
by scottcrete
thats... sounds .. scary.. .. maybe i will stick to combustion.. as i do not wanna kill myself... :(

Posted: Sat Mar 29, 2008 8:41 pm
by TurboSuper
Get them refilled, buy a reg, and build a portable pneumatic/BBMG?

Since noone has mentioned it yet, I'm going to go out on a limb and say I have no idea what I'm talking about here :P

Posted: Sat Mar 29, 2008 8:55 pm
by MrCrowley
scottcrete wrote:thats... sounds .. scary.. .. maybe i will stick to combustion.. as i do not wanna kill myself... :(
Coming from a US soldier who's served a few years in Iraq :roll: :D

Posted: Sat Mar 29, 2008 8:59 pm
by elitesniper

Posted: Sat Mar 29, 2008 9:07 pm
by MrCrowley
elitesniper wrote:you need to hard up :D :D
Your linky no worky, so i'll link to a different video.

<A HREF="">You need to harden up</a> :D

Posted: Sat Mar 29, 2008 9:10 pm
by elitesniper

Posted: Sat Mar 29, 2008 9:19 pm
by starman
MrCrowley wrote:
elitesniper wrote:you need to hard up :D :D
Your linky no worky, so i'll link to a different video.

<A HREF="">You need to harden up</a> :D
Oh geeze man, those guys were crazy.

Posted: Sat Mar 29, 2008 9:34 pm
by POLAND_SPUD
@scottcrete it is safe as long as you use steel pipes and malleable iron fittings because PVC is good for lower pressure ( about 150 psi) naturaly if you want to up the pressure and get more power you have to use stronger materials like copper or steel - that's all

EDIT
I assume you have never build a pneumatic gun...? This site is full of information that would help you to build a safe pneumatic and those tanks would make an ideal chamber (the only problem i see is getting the fitting to connect them to standard NPT threads ). It doesn't matter wheather you are going to use them or not but it is rather obvoius that sooner or later you have to build your first pneumatic. People use different materials to build their guns but I advise you to use steel and malleable iron fittings. The main advantage of steel is its strenght and the fact that fittings can be 'recycled' (it isn't possible with PVC).
You don't really have to use 400 psi on you first gun or the first time you fire your gun - but the fact that steel is so strong allows you to up the pressure if you want to