SpudFiles

I have a bit of experience with making basic pneumatic spud cannons and I have a question. I need to make a pneumatic "launcher" like this one: http://video.google.com/googleplayer.sw ... 2287&hl=en

I made a simple version (potato cannon with an end cap with a hole at the end) out of pvc, filled it with water, pumped it up, and fired. It worked very well, I felt the tremendous power. I tested it out a second time and the whole with exploded at the connections, ripping a lot of the skin off one of my middle finger. So, can anyone help me make one that wont explode?

What is that a pic of? A bike?
Edit: sorry i thought it was a pic... vid wasn't working for me..

Well you obviously did a poor job PVC cementing the joints of your first. To make a safe one use pressure rated pipe, and PVC cement properly. As for what to build just look through the site!

I will make sure the joints will be cemented. But I want to have a nozzle at the end so it sprays the water out creating a lot of thrust in the other direction.

I say you make the nozzle out of epoxy, cheapest thing your probably gonna get, unless you have a lathe. Would you other experienced epoxy casters agree?

you do know that is off jackass 2...and thats the johnny Knoxville, don't you?

http://www.youtube.com/watch?v=RSghOojD4Ko

You could buy heaps of fittings that would work just fine as a nozzle pre-made.

Yeah, can anyone point me in the right direction for a design? should i use pvc pipe? or some type of tank like they used in the video?

:laughing3: here's some light reading everything you need to know

http://www.spudfiles.com/forums/pneumat ... n-f26.html

After reading for a while my brain some times feels like this....:violent2:

Okay, so here's the basic plan, tell me what you think.



The first one has the reducers in the pneumatic compression chamber leading down to a small ball valve. The second one is the same except there is a large ball valve then the reducers. To use it, it will be filled with water, pressurized, then fired.

yea, but bell reducers are usually DWV, at least at my Home Depot
Make sure everything says NSF-PW before you buy it or else its no good
It could say NSF-PW on the outside or or the ring around the socket

Large BV with reducers, although it might choke the flow a bit, but the huge ball valve will more than make up for choking the flow.

Shooting water is a baaad idear if you fill up the whole barrel. It creates [insert wiseass physics knowledge here] that can make your gun explode.

Stick to taters

huh I think he means filling the chamber with water so it is a real rocket
am I right?
but don't use your hand for opening the valve but use a rope, radiocontrolled or something else. no matter if you fill a barrel or chamber.

TurboSuper wrote:Shooting water is a baaad idear if you fill up the whole barrel. It creates [insert wiseass physics knowledge here] that can make your gun explode.

Stick to taters

Please explain this [wiseass physics knowledge] because I dont see how it could possibley make it explode Water is heavy if you use enough but wouldnt shooting heavy things be the same.
And Ive done it dozens of times, with no explosion what so ever.

Did you fill the whole barrel?

What was the cannon made out of?

I think it's just newton's action-reaction law in action. I remember someone had the same problem back on SpudTech.