Looking to get into pneumatic spud gunning

Cannons powered by pneumatic pressure (compressed gas) using a valve or other release.
Lan
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Well, to start off, I felt it was time to add some spud gunning to my life so I looked around on the net and thought this would be a good place to start...

Last weekend i built my first gun <barrel> , but am now looking to make a more complicated model. As I said, I've done some research, so I know the basics and then some, but I have some questions...

1. I've seen the ratio of barrel to chamber is 2:1, but is that length?
diameter? or both?

2. How exactly do you mod a sprinkler valve? and what is a good brand to mod?

3. What is the "trigger" i have seen on some guns involving Question2?

I'm sure I'll have more questions, but if anyone could help me that would be great. Also any tips or links would be appreciated.

Thanks
Lan
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Hubb
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1: The chamber to barrel ratio (not barrel to chamber) is by volume. It applies more to combustions, as a good C:B ratio is needed for optimum performance.

2: This is how to mod a sprinkler valve

3: The trigger is called a blowgun. They can be found at most hardware stores. Just be sure to remove the brass tip, if any, for better flow.
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hi
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just some advise, make sure that the pipe is pressure rated, both pipe and fittings alike. if it says "DWV", dont use it. if it says "nsf-pw", then it is perfect for a cannon.


modding a sprinkler valve is incredibly easy, litterally drill a hole in the top and screw a blowgun in. there is not frills or thrills, its increadibly strait foward and easy to do.

you can get a blow gun in the air compressor section of lowes or home depot for about $5.

sprinkler valves are in the irrigation section and cost about $12. get a "orbit watermaster", they are the least expencive and work very well for a cannon.

i wouldnt worry to much about the chamber to barrel ratio on a pneumatic. just amke the chamber at LEAST half the size of the barrel and you will be fine.

example-

5 foot 1'' barrel

2.5 foot 1'' chamber, though i would suggest a bigger one around 4 feet long.

good luck.
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
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battlemonkey
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defintily get into pneumatics. they save so much time and work 99.9% of the time. u dont have to mod your sprinkler valve straight away, it works very well by itself. After just a few months i am already making a semiauto marble gun and all because of spudfiles. its a great place so hope u like it :D :D :D :D
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