a 3,000 psi cannon

[HaiThar]

Make a pneumatic cylinder with a small low pressure tank to open the ball valve. It'll probably work better than a spring and shouldn't be hard to rig up either.

If you decide to do this, which i think would increase your performance, then you will need another seperate air chamber for powering the pneumatic cylinder. If you need help with using a pneumatic cylinder or mounting it or anything, just contact the user name idiotfactory and he will help you with this. Mention me and he will know what you are talking about.

Why would you do this? It makes no sense! most of those cylinders have 1/8 ports, and I doubt they can fill that quickly. Also, the valves he will be using probably won't get the power they need to open from a pneumatic cylinder.

[grumpy]

wow , i realy did not expect that many respounces that fast. yes i will be using hpa. from playing paintball i've got scuba tanks , scba tanks and paintball tanks along with a 5k psi compressor, also a couple of 20lb co2 tanks . i do have earmuffs that i use at the rifle range when target shooting , do you think they would work? or should i get different ones?
well i had thought about mounting it to a tripod but if recoil is a problem i supose i could mount a set of motorcycle shocks to it and then mount it to the tripod, should handle the recoil.

oh yea thanks for the idea about using a pnuematic cylinder to trigger the ball valve, humphries has the purfect one, once again thanks.
http://airinc.thomasnet.com/item/air-cy ... 2?&seo=110

[DYI]

If you do this, you will be the first on the site, and it will be really impressive. You will need a relatively long barrel to make this worthwhile, but you should be able to get really high performance out of it. A recoil absorbing stand will be a necessity with heavier projectiles. On the few shots I got out my 500 psi burst disk gun (2" calibre), the stand was damaged slightly on every shot, even with relatively light (<1 pound) projectiles.

[vov35]

lol LONG barrel
and umm u might need a big stationary mount...
just like with my new gun idea: gauss gun from an MRI machine

[DYI]

Do you think you could use SCH 80 seamless steel on this? It would reduce cost significantly.

[grumpy]

unless i'm mistaken 2" SCH 80 seamless steel pipe is only rated for 2575 psi. i think i prefer the safety of the SCH 160, at least for the pressure chamber

[Killjoy]

Sch 80 2" seamless steel pipe with a material strength of 35000psi (not sure of correct)
Safety Factor of 4: 2000psi
Safety Factor of 2: 3900psi

With a material strength of 45000 psi (once again not sure which one)
Safety Factor of 4: 2500psi
Safety Factor of 2: 5100psi

All pressures are working, burst pressure should be over 7500 psi no matter the safety factor or the material strength.

Sch 160 would be the safest choice, but you could use sch 80 with out much of a risk

[grumpy]

i always stay within the working limits of whatever pipe i'm using that way the actual burst pressure of the pipe never becomes an issue, i have been accused of over building by some and i do admit to being on the careful side when it comes to building anything with high pressure. i apreciate the info though , this is were i usualy go for any info on pipes.
http://www.piping-toolbox.com/piping-tu ... s-t_6.html

[EGOed]

You need to take into account the fact that you will be using threaded fittings so they must also be schedule 160 .The weakest part of the pressurized system will always be at your threaded connections so you must take this into account and cant just design your cannon around pipe working pressures.....You will have a difficult time sealing your 2" steel threaded connections at 3000 psi .....High pressure air fittings have precision machined pipe threads or are CGA fittings with sealing faces that prevent leakage at those pressures.....The threaded valves on a 444cu/ft 3000 psi DOT tank are screwed in with a hydraulic machine ....Not trying to discourage you from trying it , but I own a paintball field and I would never even attempt to make a pressure chamber out of pipe for use at those pressures.......You can always use it at a lower pressure after you make it , but air leakage will be be a big hurdle to overcome at 3000 psi .

[spudgunnerwryyyyy]

Ok, air leakages isnt the problem. The problem is how to get this all working efficiently and seeing if this is even worth the effort.

[grumpy]

the only threaded fittings will be for the airline connections everything else will be welded, it will also be pressure tested in a water tank. i have thought very carefully on this for sometime.

[Hubb]

... and seeing if this is even worth the effort.

If grumpy gets this working, it will be worth the effort.

[Marco321]

I would take into consideration the cost per shot of the gun. Yeah it would be cool to have it shoot at 3000 psi, but say if it costs like $30 per shot, it wont see much use.....

EDIT: Also noise would be a huge factor, a large bang followed by the sound of a super sonic bullet.... Your neighbors may not like it.

Another concern would be safety, you would need a very good backstop with no ricochet, it wont be much fun to have a supersonic round hit you in the nuts...

[Hubb]

That's a lot for one shot. How would it cost that much?

[Marco321]

That's a lot for one shot. How would it cost that much?

Its helium, its expensive, and you would need alot of it. I don't know how much it will be per shot, but i know it will be a large amount i think. Maybe a whole tank depending on chamber size and tank size.

EDIT: At least, i think he will use helium.