New here, my two cannons

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
Vaeevictiss
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Fri Jan 07, 2011 5:21 pm

So this one was my introduction into using sprinkler valves. I built it a couple years ago and found it worked best...with gumballs haha. I decided on the breech load system because it was just easier for faster firing. The barrel used to be longer but it unfortunately cracked a bit and i had to cut it short. The valve is a 3/4" Orbit valve.


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My other one i built about a year ago and wanted to go big. I got the Rainbird 200-PGA 2" valve and decided upon a cam-lock system for interchangeable barrels. The 3" pipe works perfect for tennis balls and other larger objects like t-shirts. The 2" is good for potatoes and racket balls. And the 1" is really the nasty one. I managed to get a hold of some solid steel 1" ball bearings that i have found to literally be the most amazing thing I have ever shot through it.
In the past I have tried making ammo out of a solid fiberglass and delrin rods and those worked nice. I even casted a few sold lead rounds which were pretty nice as well. The ball bearings are so far the best


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My next project will actually be something opposite of this one. I wanted something more compact, because this is just crazy to hold lol. I will be making a large tank that will basically be a backpack. I plan to run a 1" hose off that tank to connect to the actuall "gun". To make sure there are no restrictions, I will have to also use 1" cam locks and a 1" sprinkler valve. This will also allow me to build additional compact cannons in the future and just cam-lock them on and off...basically the entire gun will be interchangeable, using the same hose and tank system. If it works how I want to, I will upgrade to all 2" everything so it will be similar to my current big one.
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Mr. Potato Head
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Fri Jan 07, 2011 5:48 pm

Looking good. What pressure are you shooting at? And the one thing people here love to see is damage pics!!!!!
Keep up the good work
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Gippeto
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Fri Jan 07, 2011 6:03 pm

Somebody has himself a nice cnc plasma table....oooooh the fun! :D

Might catch hell for that reducer and the fittings through the pipe wall though. :lol:

Better to use fittings and pipe with an NSF-PW or NSF-61 rating (potable water). Potable water is under pressure, and thus the pipe and fittings are designed with pressure handling in mind.

Tapping holes through two layers is the prefered method.

Welcome! :)
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Technician1002
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Fri Jan 07, 2011 6:08 pm

One of my first successful short launchers did very well with gumballs. It was coaxial so I didn't have interchangeable barrels. A 2 inch sprinkler valve. Nice find. May I suggest a thinwall 2.5 inch barrel to add to your collection. Tennis balls and cans of soda are a couple of reasons to add this size. They work well on a 2 inch valve.

My biggest concerns on the 2 inch is the chamber. It looks to be made with DWV fittings. The fill and gauge are installed on a single thickness of pipe instead of a double layer on the side of the end cap.

I would not recommend a hose between a chamber and barrel. The length of 1 inch hose will hurt performance due to the pressure loss.

A backpack high pressure supply tank feeding a regulator to refill a chamber on the gun is OK.
Vaeevictiss
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Fri Jan 07, 2011 7:08 pm

Yea I was always a bit curious about the fittings. Going through two layers is a good idea tho. I ended up using 2 part epoxy as a thread sealer tho and it has held up well so far but ill do it the two layer way on my next one.

As far as pressure ive been happy with 100psi.

That large barrel is actually 2.5" not 3, my bad. (ive also found tennis balls shoot better when wet...and even better full of water).

Say if I did the new one with 2" parts right off the bat? The hose would only need to be about 4' long.


As far as damage I wish I had taken more pics. We've shot through just about every type of electrical appliance out there lol.
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Gippeto
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Sat Jan 08, 2011 1:12 am

Vaeevictiss wrote:
As far as damage I wish I had taken more pics. We've shot through just about every type of electrical appliance out there lol.


If yer gonna be shooting appliances.....pics don't cut it....we simply MUST have VI-DE-O! :lol:

WITH sound please. :)
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Vaeevictiss
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Sun Jan 09, 2011 9:47 am

i was thinking about this some more...my whole idea with using the hose and cam lock system with my compact gun design, was to allow for the sheer volume of air.

My big one for example has a lot of air behind it when it fires. If i did a HP tank with a line feeding the gun, i would still be at a loss for volume of air. When i said compact i really meant it. It was going to be the cam lock connected directly to the sprinkler valve. If i did a HP tank, i would still need some type of resevoir on the actual gun part.

any way around this?
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Technician1002
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Sun Jan 09, 2011 11:47 am

Sheer volume is a good idea, much like filling a truck tire. The rate you deliver the volume is important in air cannons. High flow is very important. You want to deliver the entire volume in less than a few milliseconds. For this reason the hose is generally a poor choice over a relatively small chamber very close to the barrel.
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