Oh my gawd what have I done...

[Thordic]

Ok, here is a diagram I drew up. I have nothing to do with Butterfingers, I drew this myself. A couple things to note:

First off, the parts in this thing are only rated at 400 PSI. I wouldn't go over 600 PSI or so if you plan on using it much My diagram also has a couple changes off Butterfingers design, and I'll explain:

First off, Home Depot doesn't seem to carry 1.5" ball valves, 1" was the biggest they had, so I shrunk the whole design by .5" to make everything match the valve.

That would have shrunk the dump chamber, so instead of using a 2" x 6" nipple, I used a 1.5" x 8" nipple. Its a smaller dump chamber, you could use a 10" nipple if you wanted, 10" would bring you closer to the 2" x 6" volume.

If anyone has the means to buy a larger ball valve, please let me know, then I could jack up the size a little bit on mine.

But anyway, that being said, here is the diagram. Total parts cost so far: Less than $24. This isn't including loctite or PVC sealant, which I had, or air fittings, which I have, or the nitro tank, which I also have As I said, I strongly reccomend that your air source be regulated down to 600 PSI or less, or you risk serious injury.

Added on edit: I highlighted every other part with red so you can tell where one part stops and another begins

[Thordic]

I'm in the process of doing the rough physics behind these designs. Butterfingers numbers are way off because he miscalculated the size of his dump chamber.

If anyone wants to give it a shot, post your work here.

[Thordic]

Ok, I went to a different home depot today because I found out that the working pressure for the 1.5" ball valve is 600 PSI, as opposed to a 400 PSI working pressure for the 1" valve. So this one set me back $35, but I also got a larger dump chamber, etc, so mine will now be identical to butterfingers, pretty much. Heres an updated diagram:

1- 2" Black Steel Cap ($2.25)
2- 2" x 6" Black Steel Nipple ($2.80)
3- 2" to 1.5" Reduction Coupling ($2.94)
4- 1.5" Close Nipple ($1.28)
5- 1.5" Brass Full Release Ball Valve ($35.00 on sale from $41.00)
6- 1.5" Male PVC Fitting (Less than $2)
7- 5' SCH 40 330PSI WP PVC (Less than $5)

So what I have now is basically 2 potato guns I may turn the smaller one into a paint cannon for scenario games. CO2 with a reg down to a low pressure should get it under 300 FPS with a wad of paintballs Or maybe a mortar instead...

[Butterfingers]

Thanks thordic. The dump chamber size was just a guestimate. Thanks for posting diagrams. I would be more likely to be struck by lightning than to find the time to do what you did. I hate work, and school has been taking up every wink of time I have. Props to you.

That is a 2x10 nipple. Compare to the size of the 114 ci tank...

Whoops! 32.5 ci for the large nipple plus 3.53 for the small nipple so around 35 ci...

So around 821 fps... at 600 psi not to shabby.


Thordic for the trigger mechanism.

You need

2 U brackets
a pulley
a good length of cable
a heavy spring.
cable end clamps
2 carabiners or large chain links.
and a bolt and a few nuts to be drilled through the handle.


It dosent too work well if you cant slam that ball valve open fast enough.

[Thordic]

Im actually getting a high-pressure solenoid valve for free from my dad, so then I'll replace the ball valve, and all will be well

[zads27]

Re: Oh my gawd what have I done... Enter and Exit Damage!!!

Originally posted by Butterfingers
The size of the dump chamber the length of the barrel and other such fun figures the computer calculated my muzzle velocity to be over 1200 FPS!!! Yep actually faster than a speeding bullet.

My Weatherby Mark V Accumark does 3350 fps

[Micromag5371]

Oh By Golly Gee Whiz

you people dont know what your talkin about. that potatoe gun is super sweet, but if you want real fun, get a smaller barrel...one that can fit a golf ball. EVERY BODY knows how bouncy Golf balls are. potatoes, potatoes suck compared to a golf ball. if you shot a half inch if plywood with a golfball gun you would not only put a hole in it, but i can image the reflex of the golf ball knocking the foor off of its hinges. a golfball would get better effiency for air, its dimples would make it fly further, it would be faster, and it would DEFINATELY cause more damage. image hitting a stop sign. the golfball would most likely go through it, and thats kinda like having a 55 millimeter cannon thats not illegal. HAHA im so damn sinister. i think it would be fun. shoot some lowflying aircraft, or if you have enough money and time and resources, you can make a firing line of like 4 of them so you can rip them all right after each other. definately not toys to shoot people with, a spud can take somebodys head off and a goldball would implode your cranium and....
and...........
*sigh*
and im getting too worked up and emotional.
lemme know if anybodys got the nugz to make a golf ball gun.

[MagMan5446]

damn...you crazy son.

I'm gonna do it..

[BTAutoMag]

Three Men Killed By Golfball


I can see the headlines now

[Butterfingers]

im not responsible

Disclaimer:

"Not for use with golf balls"

[Thordic]

The point of a potato gun is distance, not damage. People like you will get them made illegal...

On a side note, I'm working on a design for a much more powerful gun 1000 PSI operating pressure with a larger dump chamber.

[BTAutoMag]

youi all are psycho... let me in i wanna make one!

[tunaman jr]

potato cannons

they are more popular then you think
do a search on the web you will be surprised to find a webring about them.
even an online store.
im experienced so far as launching limes till ya cant see em' i did a project with all schedule 40 pvc and a battery powered grill ignitor which works like a mini stun gun. i used starting fluid for propellant by removing the cap and using a "basketball air pin valve" (glued into a small hole in the 2 ft by 4 in chamber) to atomize the liquid right before ignition.
one time my neighbor had a flashback from vietnam and his daughter told me he thought it was mortors. that was the end of my spud cannon recreation.

[Thordic]

Rob -

I know, I've done some research online, and I also have been emailing Joel from Spudtech.com about a design I am working on

[Butterfingers]

Thordic keep me posted on your developments! I would like to know how my alpha product will do and what it will develop into. I saw his webpage that breach loading oxy propane launcher is insane!