Quote:
Originally Posted by sniperx117
DONT MAKE IT OUT OF PVC!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!11111111111111111111111111!!!!!!! !!!!!ONEONE!!!!!!!!11!!!!!!!ELEVEN!!!!
Im serious. Use galvinized metal for the chamber and then pvc for thebarrel
Ok. Let me give you my experiance with spud guns.
I have made 3- 2 Combustion 1 Pnumatic.
The basic layout of my pnu-mie was a couple of galvinized pipes connected to each other and teflon tape to seal them up inbetween. That served as my expansion chamber. The i had a 1" ball valve inbetween the chamber and my PVC barrel.
It ran on CO2. I hooked it up direcly to the expansion chamber by use of an asa and a stainless steel hose. That proved to be problematic because there was a leak between the chamber and the stainless steel hose because I had to drill a hole in the back of the end of the cannon and stick the hose in it. Even with a TON of teflon tape and paste, i could not seal it up.
I only got it to shoot once. It shot about 130 ft. accuratly. It was insane.
But after that, I just gave up. The cannon is now laying in my basement.
m now working on my new combustion.
Check out these sites:
http://www.freepaintballplans.com/la...ll_cannons.htm
http://www.spudfiles.com/ |
Well that makes for a heavy gun doesn't it? You are so down on PVC pipe. Everytime the subject comes up you scream "DON'T DO IT!!!"
I have built many launchers out of PVC pipe and not had a single problem. In fact I would say that 90% of the homemade launchers youencounter are PVC and you don't hear on the nightly news obout them blowing up and injuring people. If they were as unsafe as you seem to think they are no field would allow them for insurance reasons.
The trick is to actually know what you are doing. You need to know the specs of your materials and work safely with in those limitations. For instance3 1/2 inch Schedule 40 solid PVC pipe has a burst rating of 280PSI. Now if you are planning on making it safe you install a little $5 peice of hardware called a pop off and use a regulated air source. Get a pop off that is rated at 100-125PSI that puts you well within the "safety" range for the 3 1/2 inch pipe. Alternatively you can design the chamber to safely hold one charge from a 12 gram cartridge.
In my opinion comustion guns are dangerous by comparison. You have no way of regulating the fuel load therefore no way of regulating the firing pressure which means aside from the obvious safety of the launcher issues you have no way of regulating velocity. You also "shock" the chamber with high pressure and heat--it's an explosion in there dude. How do you think a real pipe bomb works? I used to make those too as a dumb kid.
Personaly I'd rather stand next to the reasonably designed homemeade PVC air cannon than someones idea of a "safe" galvanized steel combustion gun. The air gun will pressurize slowly by comparison then release quickly where as that fume burner will chunk the ball via a small uncontrolled explosion.
Just for infromation purposes though given the same wall thickness, the larger the diameter the pipe the weaker it is--that is true of all pipe. There are some good sites that list the pressure ratings of various pipes (doom labs portal is one if memory serves me correctly). Also when you buy PVC pipe it has the pressure rating printed on it. The one precaution I would stress other thant he basic hardware design is make sure you get the correct pipe. If you are not paying attention and just looking a price you can get hosed royaly. Make sure your pipe is not--repeat NOT vent pipe. That stuff is foam core and does not hold up to any kind of pressure. Jsut look for the pressure rating printed on the side...
anyway, if you plan on using it at a scenario, find out what their rules are for tanks etc, before you begin building as that could really set you back if you show up and they wouldnt let you use it.
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