Project #1 from Tacoma747 Category: Custom Tools (welded aluminum golfball cannon)

Well, I don't guess it is really a 'tool', unless you have a bucket of golfballs you need to get out of your way and never want to see them again, or some extra tomatoes, potatos, or anything else you want to shove down the barrel. This cannon is air powered, so based on NC laws, it is legal, and it does not use anything combustible as a propellant.

Materials are:

Large aluminum tube for chamber (pick your size)
Small aluminum tube for barrel (pick your size, mine is 1.75 .120, golfball fits perfect.
Aluminum circle for back (1/4")
Aluminum circle for front cap (1/8" or thicker)
Aluminum 'fins' to weld to the barrel to hold barrel centered when welding the front cap on (these are not visible when assembled)
Aluminum circle (1/8") with 1/4" hole in center, flexible rubber diaphragm (about 1/8"-3/16" thick works well), the rubber needs to be slightly larger than ID of chamber, aluminum circle needs to be slightly smaller.
PVC that will fit inside chamber, you can take a larger piece and cut a section out to make it smaller for a tight fit.
Ball valve, schrader valve.
Gauge (if you like)

I will go into more detail later on the assembly, I have pressurized it to about 130psi, which seems to be more than plenty, it will launch a golfball out of sight, I put a large dent in a piece of 1/8" aluminum with a frozen tomato.

http://i1120.photobucket.com/albums/...ket_96870_.jpg

we can have contest i have a potato gun lol have a gun for tennis balls also. cool golf ball gun

We need some videos of those things, lol

car drive shafts make good grape fruit guns lol

Wow... Just seen your post on the contest. I was thinking how the valve setup was working. I made one quite similar out of pvc as a potato gun. I am guessing it works on the principle of a pop off valve. As long as there is pressure it won't "fire" and when the pressure was released the air dumps... Works much better than a 1/4 turn valve.

If we could figure out a way to mount the valve so it was closer to the middle so it could be sighted in. I was thinking of a "Y" style valve that would let air in, in one position and release it in the other while stopping the air compressor air. If any of you guys could follow that. I just could not find a 1/4 turn valve that was a "Y" without going hydraulic.

With the one I built I could shoot a potato through a fiberglass car panel. I also shot one through a plastic tank. (500 gallon tank) Not a 55 gallon...

Did you weld with the rubber diaphragm in the tube??? If so any ideas on replacing it if it goes bad??? I used plastic and had to replace mine once or twice... Experimenting... Maybe the rubber would hold up much better.

BTW did you know BB guns in Michigan are considered firearms????

Quote:

---

Originally Posted by Brian Ski

Wow... Just seen your post on the contest. I was thinking how the valve setup was working. I made one quite similar out of pvc as a potato gun. I am guessing it works on the principle of a pop off valve. As long as there is pressure it won't "fire" and when the pressure was released the air dumps... Works much better than a 1/4 turn valve.

---

My attendance for this contest has been a bit off and on so I missed this the first go round too.

Quote:

---

Originally Posted by Tacoma747

I will go into more detail later on the assembly,

---

How about some of that detail? I'm having trouble visualizing how the air is dumped into the barrel.

Quote:

---

Originally Posted by redbeard

How about some of that detail? I'm having trouble visualizing how the air is dumped into the barrel.

---

If his is the same as mine it takes a little bit of thinking. Picture a large round tube, like he has shown. Then the barrel goes almost all the way to the back of it. So it looks like a tube inside of a tube. All welded in the front. Then put a thick rubber circle on the back that sits inside the large tube but on the end of the smaller one. When you fill with air the rubber diaphragm flexes forward sealing the small tube, but puts air in the larger one. When the air is released the rubber flexes toward the rear and all the air dumps right into the small tube. Instant dump.

Did some looking and found a link... These are a little harder to find but work much better.
http://www.spudzooka.net/SpudZooka/P...ans_Rev_03.pdf

BTW Tacoma took it farther and went with aluminum. I think this is close to his plan.

Quote:

---

Originally Posted by Brian Ski

If his is the same as mine it takes a little bit of thinking. Picture a large round tube, like he has shown. Then the barrel goes almost all the way to the back of it. So it looks like a tube inside of a tube. All welded in the front. Then put a thick rubber circle on the back that sits inside the large tube but on the end of the smaller one. When you fill with air the rubber diaphragm flexes forward sealing the small tube, but puts air in the larger one. When the air is released the rubber flexes toward the rear and all the air dumps right into the small tube. Instant dump.

Did some looking and found a link... These are a little harder to find but work much better.
http://www.spudzooka.net/SpudZooka/P...ans_Rev_03.pdf

BTW Tacoma took it farther and went with aluminum. I think this is close to his plan.

---

Ah, I think I'm getting it now, I was thinking mechanical activation. The pressure differential method is quite simple and ingenious.

That is exactly the design mine is based off of Rod.

Brian, the rubber diaphragm was in the tube when the final weld was laid (no other way to get it in there). The back cap (1/4" thick aluminum) was welded on first, then the internals were installed and the front cap was welded on. The distance from the front cap and the diaphragm was far enough to keep the rubber from melting. If it ever goes bad, just cut the front off, replace diaphragm, then weld it back together. I have had this gun for about 5 years with no issues out of it yet, sometimes it takes a few taps of the barrel on the ground to get it to seal, but that normally goes away after it is cycled a few times.

Quote:

---

Originally Posted by Brian Ski

BTW did you know BB guns in Michigan are considered firearms????

---

I have a relative in Canada who played with BB guns when he was in high school. Firearm registration at that time was based upon the feet per second rating. Anything over a certain limit needed a license and anything under was available to basically anyone.

Oh, and crazy, crazy instruments of mayhem and destruction being discussed in this thread. Carry on! I want to hear more .... :D

Quote:

---

Originally Posted by undercut

Oh, and crazy, crazy instruments of mayhem and destruction being discussed in this thread. Carry on! I want to hear more .... :D

---

I can't believe this video is still here... I uploaded it well over a decade ago. This is for you Undercut.... I took a pumpkin cut a triangle out of it (like you do on a water melon) Filled it with water and tossed it in the freezer in the garage... Next summer took it out... and...

http://home.comcast.net/~brianski44/...kinsnocone.mpg