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WTS: Golf Ball Gun (WA)

4K views 4 replies 3 participants last post by  THR33M 
#1 ·
Unfortunately, my county has decided to ban "potato cannons" and similar devices, so I'm forced to either mothball or sell my beloved golf ball gun.



This is a hand-built, propane-powered ABS cannon designed to fire golf balls at subsonic to transonic velocities.

It's designed with safety in mind - the peak combustion pressure generated by a stoichiometric propane mixture is considerably less than the pressure required to burst the material the combustion chamber is constructed out of.

I've built seven "incarnations" of this cannon before I got it perfect. This one is the "final product". It's shot 700-1000 golf balls with very very few malfunctions - if you know how to operate this cannon, it should go "boom" every time.

It's equipped with a simple system to meter out a precise amount of propane, calculated to provide an ideal propane-to-air ratio for the easiest ignition and most power.



There's a heavy-duty, brushless 80mm computer fan mounted in the "end" of the combustion chamber (farthest away from the barrel) that's used to mix the propane and air together, and also used to vent out the spent combustion gasses (via the large ball valve) between firings.

The ignition system is a long, thin strip of copper etched circuit board with five "spark gaps" cut into it. This strip is attached to the inside of the combustion chamber, and runs the length of the chamber, providing even, reliable ignition. A simple BBQ sparker is sufficient to drive the "spark strip" in good weather; a higher-voltage ignition source (such as a cheap stun gun or camera flash circuit) is advised for cold-weather use (propane is harder to ignite in cold weather).

The cannon is equipped with threaded adapters to allow interchangeable barrels, and will come with 3 barrels: the 4-foot barrel pictured, a 6-foot golf ball barrel, and a 10-foot golf ball barrel (if you can manage to ship it). The golf ball barrels are made of Sch.21 pipe, which has an inside diameter of 1.675". The outside diameter of a golf ball is 1.670". This provides a great fit in the barrel and does not mandate the use of any wadding.




The chamber is serviceable via removing the six large carriage bolts (which are threaded into steel helical inserts inside the chamber) and then tapping the "combustion chamber cap" (assembly with the large ball valve) off with a rubber mallet.
There should, however, be no reason to need to open the chamber for maintenance unless a foreign object were to get inside, or something were to malfunction. I haven't needed to open the chamber in about 500 shots - that time, I had to open it because the fan slipped out of place, but I JB-welded it into place and it shouldn't move again.




The only "consumables" for this cannon are Benzomatic propane tanks ($3.50 at the hardware store, and lasts for 150-200 shots) and two 9v batteries (to power the mixing/venting fan, good for 200+ shots), making it very economical to shoot - probably cheaper than .22LR even.
The electronics are contained in the handles - the batteries and switch to run the mixing/venting fan in the front handle, and the spark ignition in the rear handle (trigger).




Since you have to vent out the chamber (using the built-in fan and ball valve) between shots, and inject more propane (using the built-in meter system), the rate of fire is around 3-4 golf balls per minute for a trained operator. :wink:

I'm not going to make any outrageous, non-verifiable claims about this cannon's power, but I will say from personal experience that it can put a golf ball through a car door, and if shot at a 45 degree angle, will travel well over half a mile. It's most definitely not a toy.

With the 6' barrel, it will get golf balls going in the 450mph (660 fps) ball park, for around 700 ft/lb of energy. With the 10' barrel, they'll go around 600 mph (880 fps) for over 1,200 ft/lb.
Here's what it did to an old olive oil can (was filled with water. Projectile was a pingpong ball sized rock, shot from the 4' barrel at a distance of 25 feet or so):





It's a ton of fun to shoot. The 4' barrel is designed to be used as a "scattergun", for use with potatoes or "gravel buckshot" while the 6' and 10' barrels are the perfect diameter for golf balls.
The short barrels will throw off an IMPRESSIVE muzzle flash at night. Also, the shorter barrels create a report sounding very similar to a shotgun.

The original plans used to construct the cannon (my own design) and a detailed explanation on it's operation will go to the buyer.

I'd like to get $250 for it, but I will consider any serious offers. Buyer picks up or pays shipping.

I don't think an FFL will be required for this weapon :bier:

However, potential buyers must understand that this thing is not a toy and should be treated with every bit of respect that firearms demand. I will NOT be responsible for any havoc caused by or with this cannon.

Thanks. :hand10:

Peace,
Pete Zaria.
 
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#2 ·
Sounds like the toy of a mechanical engineer.

I made a crude potato gun years back and it was a hoot. We had several at a deer camp and mix a few brewski's with six deer hunters and three potato guns and you make memories...:rofl::rofl::rofl:
I was a school superintendent at the time and two of the shooters were my board members...that in and of itself was a hoot...we all let our hair down, so to speak.

Anyway, back to the topic at hand...
That is one slick looking 'golf banger'...seems like that could put a whole new slant on golfing in Iraq.:rofl:

Could be a lot of fun for anyone with access to golfballs and some acreage. Good luck with the sale...definitely brings back memories.

Stay armed..."FOUR, and I mean it"...stay safe!
 
#3 ·
Sounds like the toy of a mechanical engineer.
Actually, I'm in I.T., but mechanical engineering is a side-passion.

Anyway, back to the topic at hand...
That is one slick looking 'golf banger'...seems like that could put a whole new slant on golfing in Iraq.:rofl:
Now THAT would be fun.

Someone PM'ed me asking about the procedure to operate it.

1. Close the vent valve (the large ball valve at the forward end of the combustion chamber) and drop in a golf ball.

2. Ensure chamber-side valve on the meter system is closed (The second ball valve on the brass meter pipe, the one closest to the combustion chamber. This is to prevent accidentally releasing propane into the combustion chamber before the proper pressure is reached).

3. Open needle valve on propane tank a few turns to pressurize meter system.

4. Wait for PSI gauge to read 65 psi (meaning that the brass meter pipe is now pressurized to 65psi of propane). Close tank-side (first) ball valve, then open chamber-side (second) ball valve to "dump" the 65psi of propane contained in the meter pipe into the combustion chamber. This provides a precise 4% propane-to-air mixture.
Don't let the propane/air mixture sit in the combustion chamber for more than a few minutes.

5. Turn on mixing/vent fan (click front grip switch on).

6. Run fan for 3-5 seconds to allow the propane and air to mix properly, then aim and fire.

7. Open the vent valve and let the fan run for 10-15 seconds to vent spent combustion gasses from chamber.

8. Repeat from top.

It sounds complicated but it's pretty simple in practice. I can get off 4 shots per minute or so; better than most muzzleloaders! :rolleyes:

If you guys want a YouTube video of loading and firing it, I can do that.

I hope someone else can enjoy this thing as much as I have. I'll be sad to see it go. It's really too bad that the liberals in my county are banning them because of one or two people that used similar devices irresponsibly.

Peace,
Pete Zaria.
 
#4 ·
OK, asking price lowered to $200 O.B.O.

I have almost twice that into research and development on this this thing.

I'll throw in a few hundred golf balls, a 2 or 3 extra Benzomatic propane tanks, and two extra 9v batteries. Everything you need to have fun with this bad boy :hand10:

Any takers?

Peace,
Pete Zaria.
 
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