Spud guns are a staple of summertime fun for the maker set, especially on the Eagleland side of the pond, combining as they do two of our favorite things: firearms and calories. Nine out of ten Canadians agree that there’s nothing quite like a high-speed poutine — but judging by accent [Current Concept] is an American and so his potato cannon needed a little something extra that even the second amendment doesn’t protect: fully automatic firing, with a belt feed.
Like many spud guns, this one is powered by compressed air and uses PVC for both the barrel and air reservoir; unlike most spud guns, it has a steel frame holding it together, and a 3D-printed belt-feed mechanism to bring the spuds into position, with a beefy stepper motor pulling the potatoes. Of course just sticking an extra length of pipe between reservoir and barrel would just result in 80 PSI potato-scented flatulence as the air escaped betwixt the gap, so a pair of piston-actuated, 3D printed fittings slides over the plastic casings in the belt that hold the spuds. It’s not a perfect seal, but video evidence suggests it’s tight enough to get the tubers flying.
Now, there are some caveats — the air reservoir is only good for one shot, so it needs to stay hooked to an air compressor to take advantage of the repeated firings. Since it has to recharge, it’s also only firing a spud every six seconds, so while the mechanism could do “full auto”, it’s actually semiautomatic in practice as nobody’s going to sit and hold the trigger that long. Finally, we must warn you that the YouTuber behind this is trying to be funny for much of the video. Some may find his delivery leaves them in stitches; others will be left cold. There is, of course, no accounting for taste.
Oddly enough, this isn’t the first automatic air gun to grace these pages. It’s also one of the weaker potato propellers, especially compared to this MAPP-gas powered monster. Hopefully [Current Concept] doesn’t see that and get any ideas for the promised revision of his belt-fed tuber tosser, or he may get a visit from the ATF — that’s the US Bureau of Alcohol, Tobacco, and Firearms, who are way less fun to deal with than the name might imply.
Don´t let anybody say there something wrong with US/CA/AU.
An air reservoir is easier to handle than what a friend did. They used hairspray plus a candle light to use an actual fire/explosion in the fire chamber to accelerate the spuds.
Combustion spud guns are classified as firearms in many EU countries and you can be imprisoned for making one. Also, PVC is very brittle on impact and explodes into shrapnel – that’s why it’s only used for low-pressure sewage pipes. Dunno about you, but I’d rather not become a viction of my own DIY IED just to throw bits of potato around. Pneumatic spud guns are legal as long as projectile kinetic energy doesn’t exceed 7,5 J.
@Rick
I did not know that the EU would classify a spud gun as a firearm and thats sad:( However one thing a lot of spud gunners do is wrap the pvc with duct tape. While it will not prevent a PVC explosion it will contain the shrapnel pretty well! My hairspray and barbecue ignitor spud gun will launch spuds > 500 meters!
ABS will deform, not turn into shrapnel. Hdpe is also a good option, if you have a lathe.
HDPE is what is used for fireworks mortars, for exactly this reason. It turns to cotton candy when it is overpressurized.
About 20+ years ago Germans discovered potato guns.
Even the cool kids were building them.
Germans all go on vacation at the same time.
Result: French surrender.
They had to make them illegal.
This FA is what I come to HAD for.
Now to build a full auto, combustion potato gun.
75 J per shot, 4 shots/second is an aspiration.
Based on the stupid EU anti-fun brigade laws.
Note: Assuming 3900 grains of spud, 7.5 J limits muzzle velocity to about 28.5 fps.
If I were building a potato gun in the EU I’d go for small caliber.
1000grains or less of potato per shot, double that velocity.
Have to experiment (again) to find the velocity a waxy raw potato can stand.
Perhaps some kind of jacket and injected reinforcement, potato based.
Frozen would be ‘wrong’ and dangerous, make sure I don’t get caught.
Gonna be hard to load the starter fluid into the chamber 4 times/second.
So Gatling style it will have to be, perhaps 3 barrel.
In USA not legally full ‘rock and roll’ so long as it requires application of force for each shot.
Like a force return trigger.
Most expensive part will be the safety wrapper and the fuel flow control.
If I can’t get enough O2 down the barrel, NOX it will have to be.
Crazy idea: hybrid pulse jet/potato machine gun, recoil feed.
Checks ALL the boxes.
Neighborhood will love it.
How slow can I get a pulse jet cycling??
“spud gun as a firearm”
Why would you expect differently?
Some of the EU classify private thought as terrorism…
Which ones? Bullshit.
To the detractors of ignition based spud launchers… yes, schedule 40 PVC is indeed an inferior building material for the purpose. This air based contraption is safer, faster, and honestly better engineered than anything I’ve ever made.
And playing with pressurized explosions does risk both your freedom and fingers. But I must ask…
Is there anything quite as satisfying as the sound you get from an electrically fired grill igniter and just the right fuel/air mix of Aquanet hair spray?
Is good sound.
But pyromania is a long path with many rewards.
Even cold explosions are fun, nothing like the anticipation of a creaking plastic bottle.
Sure a few will lose fingers (Jimbo).
A very few will die (I saved Ken, moron was tamping down powder, wrong, while smoking a cigarette when I walked in/ran out).
Some will branch into organic chem and lose their minds (Vern, the mad bomber of mid town.)
The survivors are stronger and smarter.
I know I’m repeating:
IMHO the reason the ratio at our workplaces sucks so bad is that girls are discouraged from blowing stuff up.
Only mom discouraged me.
Dad was trying to hide his smile.
But wouldn’t provide me with fuming nitric acid, though he had access.
He also didn’t quit his job and buy a carting track for me and my bothers, like Schumacher’s dad.
Taking a slow thing you have a lot of and turning it into a fast thing you want several of. No doubt there are inherently going to be leaks with effectively having moving parts within the barrel wall, short of enclosing the magazine in a pressurized chamber the addition of rubber gaskets might mitigate some, but it would take a lot of clamping pressure to overcome leaks, something like the mechanism in a pair of mole grips might work. Provided chemical propellants aren’t a legal option, perhaps double buffering the air tank, at the risk of adding a little complexity and the associated locations for more potential leaks. Fill one air tank while you’re lining up the potato and emptying the other, short of a butterfly valve for filling from a larger reservoir [which would undoubtedly cause stress and increase the risk of spontaneous disassembly] perhaps some sort of a burst disk might work, a roll of thin plastic film, advancing it and clamping it along with the potato. Even if the repetition rate got high enough, the addition of using the airflow to push the belt through and make it fully automatic might still be a little overkill.
The second amendment actually does protect his right to belt-fed, fully automatic weapons – a limitation on what weapons you can own is de facto infringement, no matter what NPR says :) Any other interpretation is “you wouldn’t download a car” nonsense. Of course, all rights necessarily incur correlate duties – if I have a right to healthcare, someone has a duty to provide it. QED I expect my free AR-15 in the mail any day now :D
“Honey put on the hotdogs! The NRA legal scholar is here!.”
I believe I have the right to own a cobalt tamper tzar bomba.
Anything less is an infringement.
Before you call me a right winger:
I also believe:
Abortion should be legal till the 87th trimester or 4 trimesters after the fetus last askes the parents for money, whichever is later.
Free ponies for all.
Mandatory tooth brushing.
Beach houses for all.
Perpetual motion for all, repeal of laws of thermodynamics.
The 2nd Amendment, as well as the other nine original Amendments to the Constitution, are prohibitions/restrictions on the government. The 2nd is concerned with owning and carrying “arms” and, as such, isn’t limited to firearms. This is important to understand as it renders all current weapons laws in the US unconstitutional.
If Europe had the 2nd, they would live in fear of Putin…