Instructables
I had to build a potato canon for a science project and needed one where I could get a consistent launch force. The typical hairspray cannon would not be appropriate for this purpose so I constructed this air powered launcher as a modified version of Pnewton's Petard from the excellent book "Backyard Ballistics". Typical results were a range of over 300ft using a weight, nonsealing projectile, I am sure a potato would go much farther.
 
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Step 1: Materials

The materials needed for constructing the air cannon are as follows:

·shaping file
·22-inch length of 1½-inch diameter schedule-40 PVC pipe
·1.5-inch diameter male-threaded PVC pipe adapter
·PVC primer
·PVC cement
·Teflon pipe tape
·1½-inch diameter female-threaded PVC pipe adapter
·1½-inch diameter to 3/4-inch threaded PVC reducing bushing
·Electric drill with various sized drill bits
·1 rubber-coated, narrow-diameter, replacement-tire air valve
·2 3-inch-diameter PVC end caps
·Wrench
·2 9-inch-long pieces of 3-inch diameter Schedule-40 PVC pipe
·3-inch x 3-inch x 1½-inch PVC tee connector
·3/4-inch diameter short iron pipe nipple
·3/4-inch ball valve (It has also been suggested that a pneumatically modded sprinkler valve would allow for a faster and there for more powerful launch. I have no experience with this so for the sake of this article we will use the ball valve.)
·3-foot length of 1-inch diameter wooden dowel or broom handle
·Foot-stabilized air pump

Below is the diagram and the assembled materials.

SAFETY NOTE: I have received several comments regarding the use of Cellular Extruded Piping. In short - don't use it. It is not meant to deal with air pressure and could explode violently producing hundreds of deadly shards. I have not had this occur yet but if at all possible please use a better piping.
-CCCP-1 month ago

Pretty nice pipe bomb.

I still remember when I made my first one. The valve was so tight it took me 1 second to fully open it, therefore, much energy was wasted. The valve used must be airtight and smooth-opening for efficient operation. The faster the valve opens, more air can and will come out in a given amount of time. Just a reminder. And please do use ABS piping, it's safer due to its reaction to a catastrophic failure (i.e. it turns into strips and not bits and pieces similar but not exactly like a grenade, plus PVC will be hard to show up on x-ray)
Ok, let me clarify something: Combustion powered guns are better built with ABS for the reason you suggested, because the action of a combustion cannon results in an almost instant shock pressurization of the system (I.E, goes boom). ABS is better suited to quick shocks or bumps, so it is superior for combustion cannons.

ABS cannot be used for air cannons though, because it simply cannot hold the pressure. PVC is designed to hold pressures up to 500PSI+, depending on the pipe diameter. The trick is to keep the pressurized air chamber in a safe spot, or pad it against bumps. ABS can, and will, explode if you try to pressurize it.

Pnewtons Petards like this one are pretty safe as far as air cannons go.



jmlazer ilpug1 year ago
So far, ABS has worked fine for me under pressure.
ilpug jmlazer1 year ago
until it doesn't...
The trouble is that 2 years ago, most of the PVC I used wasn't pressure-rated, add to that we didn't even have ABS piping. The thing is PVC is designed to withstand water pressure. Air is a completely different fluid to work with.

Someone should seriously get a blast shield and attempt to blow up PVC and ABS pipes rated for the same pressure. That should settle the argument.
I might do that at some point. Make two air chambers of equal volume, pressurize to the same pressure, and shoot them with something.
I might do that at some point. Make two air chambers of equal volume, pressurize to the same pressure, and shoot them with something.
Hard to show up on x- ray... Way to stop people from building it
T(M)^22 years ago
Privyet, comrades.

The question I have for you today is as follows: I am looking to build an air cannon with a 6.35mm(or 2.5in., for all of you ingloskiis who still use the English system) bore air cannon capable of launching a .5kg.(1.1023lbs.) projectile 200ft. at a 45° angle. For whoever wants to do the math, what modifications should I make to the specifications above?

Sincerely,
ДЖ

de0509 T(M)^22 years ago
Not really doing much calculations, none actually, but because you are using a quite heavy projectile, you really need a lot of force. and your caliber is big. you need the ball valve to be big as well so as to not give much resistance for the air to flow. maybe try using a big ball valve or any other valves that release pressure fast. maybe 1 inch ball valve instead of 3/4. or maybe if you can use a tee so that 2 ball valves open together. that way, you have a 1.5 inch ball valve from combining 2x0.75 inch ball valve. just make sure they open at the same time. i.e. joining the two ball valve handles together maybe?
depends on the pressure you intend to use. if low, id suggest making the chamber part longer. if high pressure, i think the original should be ok. but that is to be just enough, you may want more power right? maybe double the chamber? keep note that this also increase pumping time.
T(M)^2 de05092 years ago
many thanks, de0509. I shall keep your advice on my mind and in my project.
dasvaydanya.
sjoobbani2 years ago
This works pretty well with fire extinguisher cylinders as a pressure vessel too!
TygrFr3d2 years ago
30 PSI as a high average? If you are worried about it bursting, don't worry. I have taken a 3" chamber to 120 with no issues. And if you want good groupings, maybe have the ball valve open with a tension spring and a catch, so it will open fast, and at a consistent speed.
Turtlepwr2 years ago
The fire and danger is half the fun
sci6 years ago
How much safer would it be if you use schedule 40 PVC? what would be a safe air pressure?
ilpug sci2 years ago
If you used schedule 40 for all the parts, and assembled them correctly, a safe pressure would be about 80 PSI. That said, you can go much higher. A good rule of thumb is to take the pressure rating of the weakest pipe in the system (usually printed on the side) and divide that by 2 to get your maximium pressure
waycoobeens7 years ago
Where can you find that tire valve...honestly thats the only part i cannot find...the rest i just got from home depot
Old bike tires.
I actually found a gauge and tire valve in one i use at a plumbing supply house
at advanced auto or other autoparts store.
a tire seriously, I got an old tire and ripped it out
I got mine at Ace hardware.(basically Ben Franklins)
A friend and I decided to build one of slightly different design, which also required a tire valve. We obtained ours by cannibalizing and old, broken BMX bike's front tire.
Hermes (author)  waycoobeens7 years ago
Try a car place like pep boy's. Also, you may want to check the lawn mower section at Home Depot as they may have some valves. ~Hermes
how much does this cost on average? also wat would i need to do to make the barrel bigger, would i have to chance anthing else besides the size of the barrel? also if i use this thing with about 15 psi could i hold it whiile i fire it?
by bigger i mean diameter
Technically, you could hold this while you fired it at 100+ PSI. The design of these guns is such that it makes firing while holding a bit awkward.
tulavatalo4 years ago
will this work with bigger pipe and bigger valve?
 Maybe. You'd need a bigger Air Chamber though. I'd suggest bigger than the scale your increasing it at (ie, if you double the barrel diameter, 2.5x the Air Chamber.)
ilpug Lance Mt.2 years ago
Note that with bigger pipe, the pressure rating decreases.
LX_COCOS7 years ago
nice job but ive asked my dad for permission to do this but he says it could blow up in my face is this safe? if so how can i prove it to him any help apreciated
Hermes (author)  LX_COCOS7 years ago
If you use pressure rated pipe (generally about 150 PSI) and accurately glue your joints, this is a very safe design, far safer than the hairspray cannons. The recommended max of 30PSI that I have included is a fifth of what the cannon can take ensuring that it is very safe. As long as you follow the instructions, use pressure rated pipe, glue well, and don't over pressurize, this is far safer than a conventional lawnmower... ~Hermes
30PSI??? REALLY IS THAT SAFETY PRECAUTION REALLY NECESSARY?? MY 1ST PETARD IS PVC AND MY SECOND IS STEEL. THE PVC GOES UP TO 145 PSI AND STEEL 450. MAKE A STEEL CANNON. PLUS USE A COMPRESSOR.
I would be very scared to use a cannon at 145 PSI.
Hey there...I'm pretty new here, heh. However, I'm planning on building a potato gun this year for my science project. I couldn't come up with anything, however, one of my close friends suggested a potato gun. Consider me stupid, because I think I am many times, however...wot does a potato gun have to do with science? Am not a science person at all. Matter of fact, 'tis the subject I hate viciously. And I was going through a few sites, came accross this one and noticed that you knew wot you were talkin' about. I need some help. Am desperate, I'd say. Science fair is on May 14th, I'm sure I'd get it done before that, but I need all the help I can get... I've settled down to doing a potato gun as my science fair project. If you can help me, then talk with me here...But, I'm a new comer, and I'm very ignorant of technology and this...er..site(?)/chatplace thinger...Ahem. So, I'd not know how/when to sign online. If you can help, I'd be much too thankful and you may email me at kharosh@hotmail.com Your help would be very much appreciated and some weight off my shoulders. :sigh: - Kharosh
 2 years late, but nevertheless... -- Physics entails the study of motion, force, gravity, etc. A "potato gun" is a less formal way of saying a "Projectile Launcher". In physics, you study a topic specifically named Projectile Motion. See the correlation? Air pressure is built up (in this model), and you're monitoring the various forces exerted on the object leaving the barrel.

Cheers.
Tell your dad that the teapot in the kitchen could also blow up, the oven could explode, and etc. Nothing will happen to you if you don't set yourself up for it. Example? Looking down the barrel, even when its not pressurized, is stupid. I said the same thing to my mother, back when I made my first combustion (...explosion...) launcher, and she let me do it. I've switched over to pneumatic due to school regulations.

Cheers.
im going to quote you on that first line. somehow somewhere someday ill quote you
owwio LX_COCOS4 years ago
i have fired something alot like this at 120 psi with no problems.
de05092 years ago
Hello bro. the target here is consistency right? that means something needs to be done with the trigger because opening it manually doesnt always open the valve at a constant rate. my country doesnt see those sprinkler valves, so i designed an idea to just use rubber band and some ropes. it also uses moment of force or some would say torque. check it out

http://www.instructables.com/id/Making-a-homemade-airgun-trigger-with-metal-ball-v-1/
de0509 de05092 years ago
EDIT: but its an idea though. have A levels coming up this month, its my final year so cant do much stuff other than study. you can also use the moment principles as an add on to the science fair booth, let people learn some actual science right?
jamesbid1232 years ago
cool
blazer1016 years ago
where is the cap you put the tire valve on?
also, wont you need a PSI measurer
All on the bike pump, air compressor etc
jj.inc3 years ago
I always feel bad when people have to pump it up by hand, and not just hook it to an air compressor and have a fill time of 1 second +/- 0.5
omnibot jj.inc2 years ago
Don't, that's good exercise :D
jj.inc omnibot2 years ago
Lol, at least get a foot pump, I have one of them and it works much better.
tulavatalo4 years ago

Help i pumped upp the barrel with a projectail to over 80psi and it din't move att all 

did you close the valve? was there air flowing out? if the valve is open, close it while pumping. IF the air wasn't flowing out, either ur barrel is glued shut by the glue or your projectile is so tight it chokes the barrel
 First i made it with a pvc valve for way more flow because it was 1 1/2 inch and You probably sealed the valve by letting the glue drip down. Check that and I think you will be okay.
muchachos4 years ago
stupid questions - Do you have to pump it after every shot? how long would it take to pump it up to about 30PSI?
With a bike pump, maybe 3-5 pumps should be enough. If you have a compressor then 2 seconds. If you have an electric pump, 13 seconds. And yes you have to pump it after every shot unless you have a reservoir and a blow gun valve.
dietpoop4 years ago
aaahhhh, backyard ballistics such a great book
i made on of my own and it works great its for a school project for tenis balls i moved the pipe sise up to 2 and a half
Zem4 years ago
Could you launch those tiny pumpkins if you have the correct diameter barrel?
Zerogw4 years ago
this is a nice back yard toy, i built a potato gun myself heres where i posted it, it runs 20-120 psi and is a lot more powerful than this http://www.spudfiles.com/forums/viewtopic,p,260826.html#260826
v2rocketboy5 years ago
A great build to make, I adapted your design to one made from stainless steel both the air chamber and the barrel for extra strength, added a pressure gaugle and a bike pump input. Same sort of release design but much higher pressures which resulted in a further distance, Just wanted to say thanks for your great documentation inspiring me to build this.
Hermes (author)  v2rocketboy5 years ago
No problem. I'm sure everyone would love to see some photographs!
H205 years ago
I was wondering if there was a way to add something to check the pressure.
zgr95 H205 years ago
Yes all u have to do is get a psi gauge which u can either install on the cannon or use one of those automotive gauges tht u just press up agains the tire valve
good idea but with the second idea you would have to take the nozzle from the tyre pump off the valve.
Leomage7 years ago
I built this by the directions and it works great, but just a couple things. The ball valve definitely works better, especially if you extend the handle with something and in the directions it says you need only 1 reducer bushing but you need two.
zgr95 Leomage5 years ago
I think using a push button valve is more effective but i havent tried the valve
I hope you do realize one thing, PVC isn't made for air pressure. When PVC pipe fails under pressure, it will shatter into a bunch of sharp plastic shards shooting around the place like the shrapnel out of an air rifle, for that it is. When PVC fails under water pressure, it just breaks and once the pressure is off the water, you get nothing but a wet floor. Be careful when you start missusing material in ways the manufacture did not intend. SpartanCaver
In this project u use schedule 40 pipe which can take the pressure believe me i know
Solution: if you're really worried use ABS pipe. It's rated for 330 PSI and rips when it is over-pressurized instead of fragmenting like PVC. Pneumatic potato cannons are the safest types of spudguns around, and since this design uses a bike pump instead of an air compressor there is basically no risk of the pipe breaking at all. Unless you're a complete moron and abuse the gun then there's little to worry about.
Keringkien5 years ago
Okay so I'm replying to Mr Crowley for his "uninformative post". I say it is wise to wrap any PVC and PVC-U fitting or chamber that is under any pressure with Duct-tape (Not masking tape)because in the unlikely event of the cannon exploding it will stop the shards of plastic flying into any unprotected body parts. Nice cannon mate, simpler is always better (Because that the is less chance of a faulty part) like the way you understand safety first, unlike someone >.>
MrCrowley6 years ago
Woah, is that cell core pipe you are using for the CHAMBER?! If so, cut this gun up immediately, only a matter of time before it will fail. You also used a DWV (non-pressure rated PVC) fitting on the chamber, the tee. This is also not pressure rated and could also fail at any pressure. Also, wrapping the chamber with duct tape will do absolutely NOTHING AT ALL.
good point dude.
mr. crowley is right it is cell core!
MrCrowley is right, your lucky that you did that tiny little half-turn so everyone could see the "coextruded cellular core" otherwise you would never have known. Duct tape, Jeans, Kevlar and everything else DOESNT WORK. All of them will explode, even if you put all of them. Even Kevlar will rip, kevlar is good against bullets (front on power) but it can rip easily (sideways).
umm, FYI, you CANT restart with the pipe you bilbo... its called glue and basicily you are screwed if its "bubbly"
thats why you have to restart the whole project???? duh!
do i need special ABS cement instead of PVC cement?
Hermes (author)  potatogunner5 years ago
I just used PVC cement but the stronger the glue the better.
is this from Backyard Ballistics?
Hermes (author)  atomicturkey275 years ago
Yes, as credited in the introduction.
srry forgot to read that. i just looked at pics
Tombini6 years ago
My uncle said that the best angle to fire any cannon is around 33 degrees, something to do with gravity
Hermes (author)  Tombini6 years ago
Actually it is 45 degrees. This is why I built the cannon, to test the most efficient angle and confirm ballistic theory.
Tombini Hermes6 years ago
I still think he knew somthing I didn't, we made a dry Ice cannon which was much more powerful than a spud gun and we tested it at 45 degrees and around 35 and at 35 it went further. Most of the variables where controlled.
Hermes (author)  Tombini6 years ago
Air resistance does make a difference. I used a small, heavy, and extremely smooth ball to minimize air resistance on my launch. If you are shooting something that is not very aerodynamic, a lower launch angle will give you a greater distance. This angle is not set in stone though as it varies on your altitude, weather, projectile, etc.
Tombini Hermes6 years ago
A Pasiona can is not exactly aerodynamic... Distance: 3 paddocks (around 1km) Size: 6cm diameter, 12cm high weight: 400g? Angle: 35 degrees
that's w/o air resistance, that makes a difference. how much difference i'm not sure
jendog5566 years ago
when your done making it remember don't blow your part of your face off so put the valve the way to let the air through then load the potato then shut the valve then put the air so when your looking in the valve could move some how and take a piece of your face off=[.p.s. this did not happen to me but im just warning you guys. and I was wondering if you could unhook the pump this and shoot it like a gun way.]
Yeah you defenitly can if you are using a schrader valve (tire valve), quick disconnect, presta valve etc.
I don't know about this gun in particular but mine works quite well as a detachable gun.
rowlandsam6 years ago
could u convert this to shoot tennisballs?
rowlandsam6 years ago
and what parts should i buy? thanks!
rowlandsam6 years ago
and also, what parts should i buy to convert this ? thanks!!
rowlandsam6 years ago
hey could u convert it to shoot tennisballs?
Biopyro6 years ago
HOLY CARP. Please say you aren't still using his gun! looks like you used cellular core pipe which is very brittle and not pressure rated, meaning it could explode with lots of shrapnel :O
bikerkid6 years ago
i took a valve off a bike tube
this gun is a really cool idea
codongolev6 years ago
ha.... don't shoot anything sharp, fragile, or living"
soo coooooool we are so goin 2 make 1 nd shoot ppl out of the window of my bedroom
inventive. just like my username(sarcasm) I like it.
This has very good instructions, I made it in a day. It's very fun to use. I've been shooting it into a swamp behind my house. Also another thing you can shoot out of it is the big D batteries. They go MUCH farther than a potato.(I would not recommend doing this because of the battery acid and stuff that would get into the ground)
tmarkson7 years ago
Step 3 calls for the "1½-inch female adapter to 1½-inch to 3/4-inch reducing bushing "; these are not screw threads, and the user will use cement to bind these two bushings.
he said that.
on step number 3 it says to screw male pipe thread to female pipe thread and then says "allow to cure." What does "allow to cure" mean if your screwing them together
let the cement cure i think. :S
blazer1016 years ago
hey watcoobeens, try a tire. lol
blazer1016 years ago
hey , how much does this cost
joedynamite6 years ago
hey mad magoo you could go to my website and order some pvc from me. ill give u an estimate later but just head on over to spudtopia.com
mad magoo6 years ago
Okay, first thing. The "coextruded cellular core" pipe you used is extremely weak, and I am surprised that it hasn't exploded yet. But it seems that some of the people below, such as insertnamehere, were able to locate large-diameter, pressure rated pipe that was not cellular core. I have looked all over my town and cannot find anything that is large diameter and not cellular core. Can anyone help?
pandaboy2926 years ago
they let you bring that to school? jeeze, my school i get in trouble for shooting spitballs. i`d get expeled for like a year if i took one of those to school.
in general it would be best to make the barrel and the pressure chamber next to each other and parallel. looking something like this...
(=====================)= |}
-(=================)= |}
if you get that you are pretty smart... lol...
when I made mine, i made it first with it all in a straight line, then realized how bad that could be for the valve and such, and so modified it to make it double back on itself.... i used a 1 inch ball valve and it works really well... i don't really like the sprinkler valves just in that they are entirely plastic. the ball valve that i have is solid metal. i just feel more comfortable with it. someday i think i am going to make a spring-loaded activator for it.
its actually better if the air chamber is right behind the barrel, most of my cannons are over and under tho so I'm being a little bit of a hypocrite but the air flow is better if it is straight line
your right, the only reason ppl put the tank under the barrel is to save room.
I realize for the air flow it would be better, but i meant for ease of use and holding it all together. when it is in a straight line, there is stress on the main valve, and you also have to be very careful when setting it down and such so you don't push out the schrader(bike) valve i didn't really explain what i meant very well
lebelt6 years ago
Potato Guns are fun, a few thing to remeber when making one. 1) dont use old parts, or cracked parts. 2) glue everything well 3) if your using air you want the air tank to be as large as possible, this will allow you to get more speed out of the potato (until a point). and a bigger valve also helps. And dont use too much pressure if your using pvc, or abs pipe. 4) these are illegal to use in the city. 5) if your using a non-air cannon the best fuel is eather, this stuff can be bought as a aerosol at parts stores. Camp fuel is also good but I havent used it much. Just don't use hairspray, it will give you less power and will gum up the eintire gun. 6) try not to make many holes in the gun because these will become weak spots. Nice little gun you made!
blugyblug6 years ago
In step 3 it says Coextruded Cell(ular core?) Cellular core is really weak and isnt pressure rated, that thing is going to blow up. Search Google or Wikipedia for proof
MTL hockey6 years ago
thats confusing
when your loading the projectile, would you place it all the way down the barrel, or somewhere in the middle or stuck at the top?
i made one a little different than this one and i put the projectile the whole way down it seemed more accurate that way, experiment with it a little
rawdog337 years ago
i had trouble with the tire valve cus it kept leaking,any tips?
Hermes (author)  rawdog337 years ago
Try using superglue to seal the joint. ~Hermes
pdeutsch Hermes6 years ago
Maybe someone here can help with the physics of this! My son and I built this air cannon for his science fair project. The purpose of the project was to study asteroid craters. We built two interchangable barrels (similar to other postings ... they just screw on): one is 1.5 inches and the other is 4 inches. When we fire ping pong balls (of various masses) using the 1.5 inch barrel at 20psi, we get a very nice shot. That is, the ball comes out with a lot of force and speed. However, when we fire a ball out of the larger barrel, at 20 psi, it barrel makes it out of the barrel. This holds true even when the balls are the same mass. For example: - fire 4", 35g ball out of 4" barrel at 20psi and it justs kind of plops out of the barrel - fire 1.5", 35g ball out of 1.5" barrel at psi and it would take your nose off if you got in the way! At first I thought that maybe too much air was escaping around the 4" ball, but we got new balls that are very snug. The barrels are the same length. Could it be that the friction with the larger ball is slowing it down and having a shorter barrel would give a shot with better "umph" at 20psi with the 4" barrel?? Any one have any experience in the differences between barrels of differing diameters? THANKS for any advice!!!!!
marc92 pdeutsch6 years ago
Try using a sabot (google it) such as a large splash ball or even a stuffed animal that fits down the barrel. Put the projectile on top of the sabot and fire.
Hermes (author)  pdeutsch6 years ago
This is probably because the 4" barrel has a greater volume of air. Therefore, for the air to escape from the reservoir takes less time meaning the total force is acting upon the ball for a smaller amount of time. In addition, the force remains the same as the reservoir has not changed so you are getting the same amount of force over a wider area meaning you have a much lower PSI. The 4" barrel is spreading the force out too much. You will need a larger reservoir and probably a larger ball joint (or pipe servo) in order to fix this. Alternately, if you are looking to change the project, you could try testing "asteroids" of different weights instead of different size. This could compare icy, stony, stony iron, and metal meteors. Hope this has been helpful. Good Luck, Hermes
pdeutsch Hermes6 years ago
Hermes, Thanks for the reply!! So basicly, the issue here is the volume of the reservoir relative to the volume of the barrel! I get it!!! When I used the 1.5" barrel, the volume of the barrel was small compared to the reservoir, but when I used the 4" barrel, the volume of the barrel was possibly even larger than the volume of the resevoir. Do you have any idea how big the reservoir needs to be relative to the barrel? 2x? 3x? Would you recommend I calculate the volume of the current reservoir and volume of the 1.5" barrel and find the ratio of the two. Then build a new reservoir that would provide the same ratio to the 4" barrel? My son was already using ping pong balls of different masses. We have two very nice curves of volume of the crater versus mass of the "asteroid" (ping pong balls). We were trying to compare this to the volume of the crater for a large asteroid. That is the part that wasn't working because the data we got for the large asteroid was clearly flawed relative to the other data. I couldn't figure out the problem, but your answer explains it!! I am not sure we will make the reservoir bigger at this point because time is running out. We have decided to do drop tests at various heights for the comparison between big and small asteroids. But, we like your suggestion of how we can frame the results we got with the air cannon with the mass changes we did for the ping pong balls. Maybe next year he can do a 2nd year study and we can beef up the tank!! MANY THANKS!!!!
leem19947 years ago
I have been looking at this and I am wondering how much does it cost to build this? Thanks (:)
mine cost $20
savageboy6 years ago
how high can you pressurize this?
jendog5566 years ago
i said this kinda rong i mean put the valve so it lets the air go through and then load the potato then close it then put air pressure because if its aready pumped pressure it could move from the preassure in it nd your loading the potato wile its like point toward your face and it goes off omg DEAD RIGHT THERE=[SO HAVE FUN BUT BE SAFE]
can any 1 tell me if pnuematics or haispray type guns are more powerful, ican't decide which type to build?
It depends on the air/fuel mixture in the hairspray powered gun, and how many PSI you can build up in the pneumatic gun. The pneumatic gun is safer though.
i think ill tak the safer option, cause i live in a confined space so don't want parts flying everywhere, lol. thxs
yep i'd go for the pneumatic
Ok i have built one that is quite nice, it fires marbles about 150 ft fairly powerful, but it broke a few weeks ago.
If at first you don't suceed try, try again.
yeah thats what you've got to do.
the entire idea of a pvc gun has parts flying everywhere anyways. if your unsure, don't do it. I have an acre of buffer zone before I hit anyone's house, so i'm relatively safe, I wouldn't reccommend shooting one of these off in downtown chicago though.
I really like this cannon, actually, I am making a replica of it, but twice this size :D I may post pictures of it once it is done...Thanks for the design Idea!
Hermes (author)  -insertnamehere-7 years ago
Thanks for the comment. I'd love to see your finished design. Keep us updated! ~Hermes
just finished gluing....I hate waiting...arggghhh....well, the cannon will have interchangeable barrels, one is 1.5", other is 2" and both are 4' long , and the tank is 3' 6" long and made out of 4" pipe...here's some pictures of the separate pieces drying (no valve attached yet) also, I was wondering, is force exerted on the valve, and if so, is it enough to make a break point? Thanks- -insertnamehere-
IM002386.JPGIM002387.JPG
Hermes (author)  -insertnamehere-7 years ago
There is some force exerted on the valve but it is far too little to have a detrimental effect on the overall integrity of the device. Good job on the construction, let us know how it works! ~Hermes
does anyone have ideas for a trigger-like valve system???
just reading through the comments, and thought i could answer. my suggestion is to get an "air gun"(one of those things u can get 4 a compressor, blows a jet of air for cleaning ect.) unscrew the blowing head(thats what i shall call it) and unscrew the bit on the bottom, there on in its simple, use threaded pipes and addaptors. p.s. im open 4 other suggestions!!!
say i was gonna try firing it at 300 psi would it still not break the valve?
Hermes (author)  Roflolommo7 years ago
300 psi is an EXTREMELY large amount of pressure. I wouldn't be as concerned for the valve as I would for the pipe. However, if everything is pressure rated to 300psi, you shouldn't have a problem. I would consult a more knowledgeable source than myself before you attempt a force that great... ~Hermes
im actually thinking of putting it up higher cuase the smaller pipe is rated at much higher psi like half inch is rated at 700 i think so im thinking of using like 30 feet of 3/4s inch at like 500 psi but i doupt id have a way to get it to 500 psi so its just a dream (plus ill just hide behind a tree when i fire it :) )
Just a couple of comments: 1. Make sure the valve is rated fr such a pressure. From what I can see of this design, the valve has just as much pressure on it as the pipe forming the chamber. 2. Be ready for the kick if your thinking of holding it while firing. It'll be pretty big. 3. Watch where you point it. Anything you shoot out of it with any mass at 500 psi. will be DEADLY for quite a distance. (Deadly as in causing a person's heart to stop beating and brain to stop working and having to have a funeral with a grieving family and going to jail) 4. After having followed steps 1-3 succesfully, have a freakin awesome time. If it works out, PLEASE put some pictures or something up. Or use a slo-mo camera and put the video on you tube. I wanna see this baby go!
Hermes (author)  Roflolommo7 years ago
As long as the pipe is pressure rated that high, this is a wonderful idea. Remember though, it may be a little unwieldy (especially at 30 feet). If you do end up creating this behemoth of a cannon, you may want to extend the barrel to compensate for the larger volume of air you know have to gain a greater distance. If you want, I could try scale the current design to calculate just how long the equivalent barrel should be. Good luck regardless! ~Hermes
can you show you made the interchangeable barrels
sure, here's some pictures, I hope they help! the barrels just screw into the sprinkler valve
Picture 153.jpgPicture 151.jpgPicture 152.jpg
special k 7 years ago
if you stuff a plastic bag down the barrel, it will be able to shoot anything out of it, as long as it fits in the endlike rock............
dchall87 years ago
I built a modified version of one of these right after Backyard Ballistics hit the shelves. I shot it about 5 times and think I got scared. I was pressurizing to 100 psi with a bicycle pump which was exhausting, too. My first shot was from the middle of a park toward the woods about 200 yards away. The potato was still going up as it crossed into the woods. The last shot was from all the way on one side of the park toward the woods. I'm guessing it was about 10 football fields across (1,000+ yards). I think the potato landed in front of the woods but we never found it. We also shot at a piece of wood leaned up against a telephone pole about 50 yards away. Aiming wasn't that easy but my buddy finally hit it. The potato disintegrated leaving only a damp spot the size of the gun barrel.

A potato fired from gun pressurized like that could easily kill someone or break bones depending on where it hit. This thing is a potato cannon, not a gun. For a 3-inch diameter barrel at 100 psi, you have 700 pounds of force acting on the potato to push it out of the cannon. If friction losses down the barrel were even 200 pounds, you still have 500 pounds coming out of there.

After my demonstration I don't recommend going to that high a pressure. I had to do the experiment as air pressure guns were pretty new at that time. Check the pressure rating on your pipe. Note that the smaller diameter pipe has a higher pressure rating. I would not exceed 1/2 the rated pressure on any pipe when it is brand new. With time and use, I would back off on the pressure. Aluminum is especially bad about being pressurized and depressurized, so I would not use any aluminum parts. Seems to me copper would be bad, too, but we weren't taught much about copper in airplane school.

If you are worried about the PVC shattering, you can wrap it in polyester rope. I like the pink and white Lehigh brand that you can get at either Lowe's or HD (but not both for some reason). Still I would not exceed 1/2 the rated pressure on the pipe. Even wrapped pipe is a hazard, so don't think this makes the danger go away. The more wraps around the pipe the better.

The electric solenoid valve I used, from Home Depot, worked on 9 volts, so I just used a common 9-volt battery and a push button to activate it.
thanks for the more detailed information. here is my design:
IMAG0044.JPG
Ora7 years ago
Can anyone point me in the direction of where i could buy a simple electronically activated sprinkler valve?
Hermes (author)  Ora7 years ago
Your local hardware store should have all the supplies you need. ~Hermes
dadumbplace7 years ago
awesome man i wana make dis but do u hav any idea where i'd get the presurised container from
Hermes (author)  dadumbplace7 years ago
Your local hardware store should have all the supplies you need. ~Hermes
rawdog337 years ago
I had tons of trouble building this,its still sitting in my garage.Finding the materials was hard cus i couldnt really understand your material list
Hermes (author)  rawdog337 years ago
The things you need to purchase are: 1½-inch diameter schedule-40 PVC pipe 1½-inch diameter male-threaded PVC pipe adapter 1½-inch diameter female-threaded PVC pipe adapter 1½-inch diameter to 3/4-inch threaded PVC reducing bushing 1 rubber-coated, narrow-diameter, replacement-tire air valve (for a car tire) 2 3-inch-diameter PVC end caps 3-inch x 3-inch x 1½-inch PVC tee connector 3/4-inch diameter short iron pipe nipple 3/4-inch ball valve or solenoid valve 3-foot length of 1-inch diameter wooden dowel or broom handle Just bring this list to your local home improvement store and ask for help in procuring the materials. ~Hermes
knexer17 years ago
Did you take this idea from the book "Backyard Ballistics"? The design of the cannon and the way you wrote the instructions were almost an exact replica of the pneutons petard in the book.
Hermes (author)  knexer17 years ago
Yes, this design is heavily adapted from the book. However it is not an exact copy and I feel everyone should be entitled to all information. So here it is! ~Hermes
piromanic7 years ago
howe much dos it cost to make
mines going to cost a bit less then 40 dollers and im using pvc rated at 330 psi
Hermes (author)  piromanic7 years ago
I don't remember but I certainly can't imagine it costing more than about $20.00. Hope that helps! ~Hermes
Great idea! I myself have a nice potato gun with a large propulsion chamber that I run off of right guard deodorant, using a decent grill sparker I bought at Walmart for around $15. This is a good idea, and I plan on making a pneumatic(air pressure) powered potato gun some time in the near future, the only thing is... you should have made it out of all threaded aluminum piping. PVC can't withstand the higher pressures, so threaded metal piping is the best if you want to make a propane or pneumatic gun. And a tip for anyone who wants to make a potato gun, if you're using PVC, do NOT get cellular core pipe! It has air chambers that make it weaker when put under stress, and can be EXTREMELY dangerous! If you want to be 100% safe when making ANY kind of potato gun, pneumatic or otherwise, use copper or aluminum piping. Instead of possibly shattering and causing serious injury, upon failure they instead leak.
Well, I do agree with you to some extent. Like with propane. Propane is definitely not as high PSI as compressed air in pneumatics. But honestly, who wants to stop at 100 PSI? When I made a pneumatic I'm going to be going to like 250 PSI, maybe more, but I'm going to use metal piping so there is no chance of injury. The more you use something, the weaker it gets, like PVC. And since PVC can shatter, I'd suggest not risking PVC piping with pneumatic potato guns. And where have you seen PVC with pressure ratings over 700 psi? The common PVC used in water systems isn't rated anywhere NEAR that high. And I do understand that metal piping will be more expensive, but I'd wager so will PVC with pressure ratings on the higher end of the spectrum. I'd rather spend more and make a gun out of materials that have a 0% chance of injuring me, unlike PVC could. Even if it's a slim chance, it's a chance I'd rather not take.
That is complete overkill. A metered propane combustion will provide you with a short duration of pressure peaking at under 90 psi under perfect conditions. Pneumatics can be built with PVC with no worries as long as you use NSF_PW pipe that is pressure rated. PVC is rated from anywhere between 100 psi and over 700 psi. Most pneumatics only use around 100 psi. So if you use the right pvc pipe you will be fine Plus its cheaper and metal is expensice in large sizes.
phillsgreat7 years ago
mine cost around 50 dollars but that kinda high because i used very good pvc and i altered it a little added some things
I made this project with my children today. When you get ready to make this project, be sure to add an extra nipple and reducing bushing to the list. so the parts list should look like this: • 22-inch length of 1½-inch diameter schedule-40 PVC pipe • 2 9-inch-long pieces of 3-inch diameter Schedule-40 PVC pipe • 1 ½ -inch diameter male-threaded PVC pipe adapter • 1½-inch diameter female-threaded PVC pipe adapter • 2 1½-inch diameter to 3/4-inch threaded PVC reducing bushing • 3-inch x 3-inch x 1½-inch PVC tee connector • 2 3-inch-diameter PVC end caps • 3/4-inch ball valve • 2 3/4-inch diameter 2 inch iron pipe nipple • 1 rubber-coated, narrow-diameter, replacement-tire air valve • PVC primer • PVC cement • Shaping file • Teflon pipe tape • Wrench • 3-foot length of 1-inch diameter wooden dowel or broom handle • Foot-stabilized air pump
Wow didn't know that you cannot put bullets on this board. So all of the wierd characters above are suppose to be bullets. I hope it saves you a trip to the hardware store!
wonton7 years ago
i forgot 2 add i am the stupidest kid i know wonton
wonton7 years ago
i got mine with preasure rated stuff up to 120 psi works fine ty so much 4 the instructions wonton
carcrazy2477 years ago
I built one much like this last night but i think i messed up by making the reservoir exactly the same size as the barrel If i increased the reservoir size would my distance increase? I'Il add images later
Hermes (author)  carcrazy2477 years ago
Hey carcrazy, Yes, increasing the reservoir should increase the distance but only to a certain point. After that, you are simply increasing the number of shots you can make, particularly if you use a solenoid valve, an addition that will greatly add to the range and accuracy of your cannon. I'd love to see some photos of what you have built thus far... ~Hermes
1weasel7 years ago
I had a friend make one of these, same principle, with the air chamber and everything, but his air chamber was equal to the size of the barrel (equal size PVC under the barrel) and he used a silinoid valve from an underground sprinkler system. It worked well, and he could get more shots per tank
Hermes (author)  1weasel7 years ago
Thanks for the comment. Yes, the solenoid valve has been mentioned several times and I would highly recommend it to anyone looking to build one of these cannons for themselves. ~Hermes
This is a very nice, very clean design. Only use pressure rated pipe though! If there isn't a pressure rating on the pipe it isn't pressure rated. With pressure rated pipe, you can take the pressures as high as the actual pipe is rated (generally well over 150 psi, especially on smaller diameter pipe like this). For more spud gun stuff, check out www.spudfiles.com
Hey, this is really nice... but in the effort of being kewl and what not just though t i would add that you can use a solenoid vlave, like you would use for watering, to release your air pressure. The solenoid allows for a much quicker, fluid release of all the air. Usually the one inch is the standard size that people use. If you go to radio shack you can get some kewl switches and what not to control the solenoid. Also, when i built my air cannon I used a tire valve for a car tire, from like pepboys and to fill it we usually went to about 100 to 120 PSI with an electric pump - The guage on the pump malfunctioned and after about 15 minutes of pressure build up, the PVC failed, but it was loud and not so explosive. But none the less, be careful with it... A fun little trick: if you buy paper dixie cups you can cut them to just fit your barrel of the cannon and allow you to shoot anything that is smaller than the cannon, even for things that fit pretty snuggly, the dixie cups can always help maximize the thrust from the air pressure _
I agree, the solenoid valve is definately a step up from the standard ball valve, and a diaphram valve is a step up from that. There are plenty of other valves on the market, some more compilicated and expensive than others....Look Here
All in all, this is a very well done design. You gotta love spud guns.
Hermes (author)  laxplayer_137 years ago
That's a really cool modification. The Dixie cups are a great idea. It's always wonderful to see people modifying designs. Keep up the good work! ~Hermes
moses7 years ago
Sir Hermes, you suck as much as your instructable. But it is very creative. Good show, chap.
Hermes (author)  moses7 years ago
Thank you. I value creativity over many other things. Also, as evidenced by your quasi-friendly comment, I can't suck too much... ~Hermes
snakeblack87 years ago
yo you can put < 100 psi in this thing
to get less leaks you can put a bike valve with threads
Esarai7 years ago
I like the design. how many pounds per square inch can your air tank hold? I've got a special project going, but we don't have the air tank. we need good pressure+volume, an I was thinking of building one.
Hermes (author)  Esarai7 years ago
I generally do not surpass 30psi in my tank though the PVC is rate to 60psi and the joints to 120psi (supposedly). Now, I am not one to tempt fate though if you need a higher psi you could certainly do it. ~Hermes
we made also a potato cannon, but with an compressor. did you chose the bicycle pump because it ca produce more presure?
Hermes (author)  casvandegoor7 years ago
I used a bicycle pump as I have several lying around. In addition, it allows me to fine tune how much pressure I insert in fairly efficient manner. ~Hermes
thanks
uvalacrosse7 years ago
thanks dude- mine shot like 150 yards... but howd u get the bicycle valve to stay in the end cap? mine wouldnt stick and the air leaked... great design though!
Yea, wow, same here. the only problem i had was realeasing the valve in time, are their any other ideas other than a ball valve? thanks for the plans man.
Hermes (author)  uvalacrosse7 years ago
Try using a little glue to hold the valve in. Good luck! ~Hermes
wonton7 years ago
just thought of making it with the chamber extended back to it is not on your shoulder but farther back also i would turn the chamber in to one straght pece so i could put another piece of pvc over the chamber to make it so if it does break it wont blow up in to a milion pieces near my head
wonton7 years ago
i would use the preasure rated stuff and only pump it up to 20 psi thank you for the advise great idea
hoss087 years ago
Hey... me and a few freinds built some much larger cannons.... If you have pressure rated pipe most cannons can go up to 150 PSI. Now... this is IMPORTANT... PVC fails horribly!!! DO NOT GO OVER THE LIMITS ON THE PIPE. Also let the cement cure completly before using the cannon. Have Fun!!! BTW apples going over 300 yards is really cool... 3in PVC will fit apples and water bottles.
DanYHKim hoss087 years ago
I must agree with the point about PVC pressure failure. It makes me shudder to look at Potato Cannon pictures where the shooter holds the cannon on their shoulder. If the PVC were to explode, perhaps due to the repeated stress in the combustion chamber, it could drive a shard of PVC into the shooter's brain. I imagine it's only a matter of time before one of these cannons fails while resting next to some person's head. I think it would be better to pressurize the cannon remotely.
Hermes (author)  DanYHKim7 years ago
Exactly. That is why I have strongly recommend not filling the cannon past 30PSI which is well below the pressure limit of the weakest part. This ensures that failure is far less likely and should it occur, it will be far less. I also agree completely with putting the cannon on a shoulder, that is simply crazy. ~Hermes
BobertXXL7 years ago
im trying to built one that shoots catolop i made a potato pne all ready
wonton7 years ago
shoulder mounted mabe
MikeAnIke7 years ago
I think this thing is way cool!!!!
snakeblack87 years ago
what topdogger saying is good but if your poor like me you get the ball valve and put a spring on it then put the end of the spring on the gun than get a pin or some thing stand back a pull a strig that tided to the pin
snakeblack87 years ago
now if you wont to bild a bigger gun http://www.instructables.com/id/ED934PYWOSEWP86FIG/
yo, on step number 3 it says to screw male pipe thread to female pipe thread and then says "allow to cure." What does "allow to cure" mean if your screwing them together
hey, i built the cannon but when i pump it up, the air comes out of the bike valve and it doesn't work as well. What should i do?
Hermes (author)  pillsberryhitman7 years ago
Sorry about the delay in my answer... I didn't have this problem but it most likely caused by the fact that the hole for the valve is to large. Try using a sealant (caulk, silicone, etc.) to plug the hole around the valve. If this does not work, your valve may be defective. To ensure that it is air leaking, make up some soapy water and place it around the valve. If you see bubbles as you pump the cannon, then air is leaking. Go ahead and seal the valve and it should be fixed. Hope this helps! ~Hermes
why would you use PVC cement if your screwing it together
yo why would u use PVC cement if your screwing it together. also, on the materials list i think u need one more nipple.
yeah but how do you put cement if your screwing it together. also, can you get a bike valve by itself?
im building it now and its awesome. im just thinking what i could shoot other than a potato
Hermes (author)  pillsberryhitman7 years ago
You can shoot anything that fits into the barrel. Remember that if it doesn't fit in perfectly, try using tissues or paper towels for wadding. *Required Disclaimer* Also think about what you are firing. Don't shoot animals, explosives, etc. Be Safe and Have Fun! ~Hermes
Hermes (author)  pillsberryhitman7 years ago
You need to secure the screw part to the barrel so that you can screw and unscrew the barrel for cleaning or possibly changing the sizes. ~Hermes
Hermes (author)  pillsberryhitman7 years ago
Thanks. It should read:

Attach 1½-inch female adapter to 1½-inch to 3/4-inch reducing bushing using PVC cement and allow to cure.
Screw male pipe thread adapter assembly to female pipe thread adapter assembly carefully.

~Hermes
how fast does it go wen its between 30-60 PSI
can you get bike valves by themselves or do you have to buy it and cut it off yo
Hermes (author)  pillsberryhitman7 years ago
Just realized you said how fast... I have no idea, but you could calculate that fairly easily with some kinematics equations. ~Hermes
Hermes (author)  pillsberryhitman7 years ago
My cannon when pumped to about 30PSI will obtain a reach of about 200-300ft with a non-sealing projectile (similar to a golf ball). If I were to use a potato which will create an airtight seal, the range is GREATLY extended and I have no idea what kind of distance you will get. This is not as powerful as the typical hairspray cannon but is generally more accurate and way cooler. No explosion here just the loud whoosh of the air leaving the barrel. Did I mention the gun is accurate... ~Hermes
whats the max PSI that you can have?
Hermes (author)  pillsberryhitman7 years ago
I generally don't surpass 30PSI but I'm fairly sure it could take all the way up to 60PSI without to much trouble. Just be careful when you do it and watch for leaks... ~Hermes
topdogger7 years ago
Here are the pictures. If you look at the close up of the electric switch you will see I put extra glue over the joints. Just another thing that doesn't hurt. You will most likely end up with a ton of extra glue. I did it on all joints so I could tell if they moved. BTW, I made an additional 2" barrel that simply screws into the electric switch in place of the 1.5" one. It PERFECTLY fits an empty cocking tube and that seems to be the perfect ammunition. I've had it totally compress the tube and get stuck in the ground from the force of 50 PSI. That what I've been consistantly running it at without a problem.
dscf0207.jpgdscf0209.jpgdscf0211.jpg
Ive started this project based on your design, and ive realised, that i dont know what to do with the wires coming out of the end of the sprinkler valve. How did you add the push button, and hook it up to your car battery? More pictures of the wires would help, I cant quite see how the wires are put together, or what they attach to first. Do you know where I could get one of those push buttons. Great design by the way, Ive made potato guns before, but never with an sprinkler valve.
The wiring was very simple. What I did was I took two spare battery clips like the one shown in the picture. Now if you look at the clip you will notice there are two bolts that clamp down a piece of steel(normally used to clamp down a 4guage wire to a starter positive line). What I did was I wrapped a wire around one of those bolts and tightened it down so it wouldn't come out. I did this twice so each clamp had one 5m wire on it. I then connected ONE of the wires straight to a wire on the sprinkler valve. For the other wire I cut it in half and hooked the push button in between it. I then connected the remaining end to the battery. I picked up the sprinkler valve from Home Depot. BTW, I have been experimenting with the gun lately going higher and higher in the pressure regions :p While out of town using a pump wihout a guage on it I was pumping up the cannon while talking to someone. By the time I noticed how much pressure was in the tank I could fully compress the bicycle pump and it wouldn't let the air into the potato cannon until the last 1/2" of the stroke! After one bicycle pump broke from extreme pressures we used another one with a guage. The cannon had handled 90PSI... Right now I would like to point out the following: ABS breaking point - Atleast 120PSI Sprinkler Valve Breaking Point - 90PSI If you make one using my instructions DO NOT take the cannon over 90 PSI. I would recommend a max of 60. Firing a potato using a 2" barrel(another goody I modded up) at 90PSI will result in potato chunks the size of peas. But anyways, have fun with them. Something to try is shooting a drano bomb with a air powered potato cannon at 90PSI. Thats pretty fun to :p
potatogun.jpg
I forgot to add... Using the push button DOES require a battery. You could however use a small battery pack that would fit in your pocket. I just think its more fun when people see the things wired to your car. Man do they start running! The sprinkler valve I found had a manual switch to open the valve. Its a very small switch so like the push button it releases the pressure a lot faster then a large handle wood. The switch also slides VERY easy with no resistance even while under high pressures.
And also, do you need to have it connected to a car battery, or power source to use the push button. I know you do for it to act as a air compressor, but if you only want the automatic push button?
where did you or where can I find the 12vdc electric air solenoid. I want to use mine with a small ride-um toy 12vdc battery and a little 12vdc car compressor. and 2 doorbell buttons. Load the barrel, push one button to quickly charge pressure from the pump into the pressure accumulator tank and the other button to discharge or fire the little beauty. The battery, charge compressor, charge button, will be mounted on a type of mortar base plate that will have weight and area to keep the base stable during recoil. The fire button will be on a lenthy halyard incase the pipe decides to fatigues after repeated fireing or I leave the pump on a LITTLE too long - he he he :) :). Those little compressors heat up if used constantly for 20 minutes or more. I always add a couple drops of oil to the air intake of the running compressor which atomizes and lubs the crankshaft, pushrod and piston then run it for a minute to blow out the excess oil. .I find a lot of useful goodies in in the American Science & Surplus (A.S.S.) catalog or at their website. Other than enjoying the simple pleasures of scaring the squirrels that keep stealing all my bird seed, I hope to do something like pumpkin chucking and lyle gun work at the lake shore Now how about the solenoid ???
son justopped by and asked how this it would work for a paint ball mortor for surgical tubing pumped full of paint. I will see what I can do.. Anybody know how to make the paint shells ???
BobertXXL7 years ago
How far does this go with a tennis ball
kaboomspray7 years ago
im planing on making one that shoots tennis balls up high in the air, and on adding parashutes to them
quote: "DO NOT shoot pointed, explosive, fragile, or living projectiles. I am not responsible for any of the damage you may incur in such a case." ok, WHAT am i going to shoot out of a potato cannon thats LIVING?... wait... i've already done that.... is there cruelty to frogs laws?
well, duh... air pressure gun, firing a can or two of the beast (milwaukee resident nickname) of course its gonna f&$% some $H!7 up!
Nice. Here's the same idea with different projectiles and targets.


U got that off funnyjunk.com didn't U
Nope, it was just featured on YouTube when I was checking something else out.
Bravo! Probably the most enjoyable Instructables video I've encountered. An air cannon is now on my to-do list.
it was not his gun though!!!!!!
That... was beautiful... I wish I had a high speed camera :P
You can use a regular camera, too. You can't quite slow it down this much, but at least quarter-speed. Check out ReTimer. It fills in the frames.

Here's a bike flip and a dune buggy roll that show before and after.

I'm gonna check out the free trial to see how well it works.
thaT is some POWERFUL gun if it can smash things like that
j.w_lewis7 years ago
nice, i like top dogger's idea about the steel straps
irwinner7 years ago
you should replace your ball valve with a pnuematically modded sprinkler valve, the cannnon will perform much better (cause sprinler valves open much faster than ball valves)
Hermes (author)  irwinner7 years ago
Thanks for the tip, I added that idea.
speedcat137 years ago
Is this william gurstelle's "Pnewtons Petard"?
Hermes (author)  speedcat137 years ago
Yes, it is based upon that design.
topdogger7 years ago
I just built one today. I will try and get a few pictures posted up. I used black PVC pipe I often use on houses when doing construction work. I had 3" diameter pipe lying around so I used that. I went to home depot and picked up the following: 1 - 3' of 1.5 inch PVC pipe(black) 2 - 1.5" diameter female pipe connectors with threads (1.5" pipe insert to 3/4 threaded insert) 2 - 3/4" ready rod like inserts. Basically just threaded sections of plastic. They connect the female pipe connectors to the switch. 1 - 3" to 3" to 1.5" t connector 2 - 3" pipe ends 1 - Can of PVC cement 1 - Irrigation switch. Rated for up to 90PSI of water pressure. Its got electric wires for push button ignition or a manual switch to open the valve. $25 I would highly recommend the irrigation switch. It is WAY easy to use and setup. Not to mention it is a lot quicker. Plus the added feature of a little tiny manual open switch is handy. I jerryrigged the power wires for the switch to two brand new battery terminals. I simply hook the terminals up to my car and carry around an air compressor. Oh, almost forgot. I went o sport check and asked for a tire valve. They didn't have them but their repair guy went into the back shop and gave me a blown out tube. This works even better. I cut the tube into a 3" circle around the bike valve. I then pvc cemented that into place in the center of a 3" end cap. That way the pressure holds the valve shut for added security. The one I built was built to last. I've run it up to 60 psi without a problem. The electric switch works awsome with a pushbutton I rigged up. I press the button and its an almost instant shot. Because it shoots from such a high PSI I was then able to add a few feet of wire between the switch and the cannon. So I can be a ways away. I will highly suggest putting some steel straps around the 3 way connector overtop of the 1.5" outlet. That way since there is a lot less surface area with the glue it will be to hard for pressure to burst that joint. I ran my gun at 60 PSI 15 minutes after putting it together and I noticed the joint slowly pushing away. I will be adding a steel strap after it dries. I better mention to that the switch I have automatically closes! This is a very handy feature. Infact a lot of times if I press the button a second time after firing there will still be pressure in the barrel!! Thats how fast the electric switches are. I'll try and get some pictures tomorrow.
JethroWho157 years ago
that video was awesome. the whip cream rocketed off propelled by whip cream
WolvesOfWar7 years ago
NICE ONE DUDE< ill make one
iman7 years ago
dude thats awsome Kudos :)