SpudFiles

anyone know pressure ratings for schedule 40 aluminum tubing sizes 2, 3, and 4 inch? or possibly where i could obtain this info? been kicking around the idea of all aluminum gun with a piston valve set up for high pressure. i have ready access to about any size or shape aluminum you could imagine. also have access to uhmw(ultra high molecular weight plastics) for pistons. i work in a machine shop with 5 cnc milling centers and two cnc lathes. also have access to kevlar sheeting which could be adhered to the cannon for added strength and added psi capacity. looked in my machinist handbook today for pressure ratings charts but none were available. the writing on the tubes dont include psi ratings. thanks ahead for any info. dan

I can't seem to find my main reference site link at the moment but http://www.rainforrent.com/products/Pipe/pipespecs.htm should be a good alternative...

perfect! thanks

the pipe on that link was pretty light weight stuff and a low strength alloy.if anyone finds anything else on schedule 40 or 80 please let me know. preferably 6061 alloy

Try Googling for spec's... http://www.charlottepipe.com/Documents/ ... Manual.pdf is yet another reference that probably gives more information than you need for PVC and CPVC schedule 40 & 80... T6061 Aluminum would be approximately triple the strength at the very minimum... Big bore air rifles are storing 3000psi in their chambers without any problems...

Chaos might know he has some aluminum cannons.

Are you wanting to know the pressure rating on T6061 Aluminum tube or pipe?

Cannon Freak.

seamless pipe or tube, either one. i understand that 6061 and a particular 20 something series are the strongest alloyed pipes or tubes. i would have thought 7075 but i was told otherwise. i want to use aluminum instead of steel because i'm planning on having a high density plastic piston with a disk of cold rolled steel attached to it. then im going to use a strong electromagnet to release the piston. the magnet will hold the piston against the barrel to seal until the electric current is cut off which will then activate the valve. therefore the chamber and barrel must be non magnetic. enter the aluminum. if this works it should be a very clean looking cannon without the need for sprinkler or ball valve to dump the pilot.

Steel is actually stronger per given weight, but as you state with a magnetic system you would be in the right to use aluminum. 7075 is stronger BTW. You can find the tensile strength to determine psi rating from the kaiser or alcoa sites. The magnet valve you speak of has some issues, mostly that you should use a solenoid piston that releases the air when it is charged to prevent a misfire if your battery goes weak or loses contact. A positive force piston valve would be a better way imho.

I can see issues with that. Too many variables to try to work out. There has to be room for the piston to move back. If there is pressurized air behind it, it won't move unless you exhaust the air. If there will be no air behind it, the piston has to be perfectly airtight and the chamber filled from in front of the piston. The magnet will have to be strong and reset the piston well. The piston will also have to be exactly the size of the barrel or even "cork" it slightly or the chamber air will be able to push it back.
For all the effort involved you can minimize your pilot volume and make a very small exhaust valve from brass fittings that looks like a real trigger.

Solar wrote: A positive force piston valve would be a better way imho.

sorry to hijack but what is the difference between a "positive force piston valve" and a regular piston valve?