SpudFiles

this might sound comletly nuts and it might be but i was thinking making a potatoe laucher using a scuba tank as the air source. This is because the scuba tank is somewhere along the line of 3000 psi so you could get a big kick out of that. The only problem is the barrel i was wondering if anyone knew the psi that a 2 inch peice of steel pipe could withstand. thanks and anyideas would be appreciated.

And dont tell me i am crazy i know.

Ok I won’t.
They use it in steam engines. They reach vary high pressure, just how high, I’m not sure.
So it may work but…

Thanks and to check my sanity would you launch a gun like this.

How much do I get paid?

I wouldn't try it. SCUBA tanks are pretty heavy and expensive. If it backfired, it could explode or spontaneously combust. I don't think you could let the air out in the correct increments to do that anyway.
I always see the pessimistic view of everything....

Hook a hose up to a short steel barrel with a steel fitting on the back that threads down to whatever type thread a scuba tank hose would take, then find yourself a 3000psi blowgun and add it on the line, load some ammo and quickly tap the blowgun.

What PCGUY suggested. Also, please post in the correct sections. I've moved three of your topics, and notified you of it.

True, you'd get some serious recoil from 3000psi letting rip.

I've just seen some 208bar (3000psi) solenoid valves. You need to pay about the same amount as someone might spend on an entire normal cannon for one of those and the bore is in fractions of inches.

Anyway make sure you wear hearing protection and don't hold it.

I havent built it yet i am just deciding if i should because i am a junior high student and i dont have a ton of money.

Honestly, it sounds like a cool idea, but analyzing the risks and cost, I wouldn't do it.
(Hey i'm a junior high student too!)

It would be very cool, if you were doing it in a 2" pipe with a valve worth using, consider the massive recoil from the air alone!!

Not to mention the massive sound you'd get when you fired it. 3000 psi + probably breaking the sound barrier would probably result in deafness.

I wouldn't do it.

Use double ear protection(little ear plugs and big ones used when firing a gun) to reduce the chance of going deaf and make a VERY strong mount for the gun because the recoil could launch you back a ways or brake your arms.

the barrel you use should be at least 5 mm thick steel. A scubatank is 5 mm to.

But nevertheless, I wouldn't dare making such a gun. And if I would, i would make a steel piston valve. If you'r gonne do it, do it properly.

@Hotwired...any chance of a link to that 208bar solenoid valve (or others) please?

@s18022....a good starting point may be to look at the seamless tubing used for hydraulic rams etc. on JCB diggers and suchlike, although you may find it prohibitively expensive. There is a place not far from me that sells it and I'll be checking out what they have some time in the near(ish) future with regards to a project of my own. If I find out anything useful I'll let you know. Meanwhile, don't do anything daft with inferior materials.

PS...This is my first post....hi all!
I'd just like to say how impressed I am by the site and the inginuity of some of these spudgun designs.