Have you ever felt a desire to launch a potato into the sky at a high speed? Or maybe on the colder side, be a one man army in every snowball war with a pneumatic snowball launcher? Yes? No? Maybe? Well, in this tutorial I am going to show you how to do just that, with your very own air cannon! Before we get started though, I have to add a disclaimer:

Disclaimer: I am not responsible for any injuries related to or having to do with this device. I am also not responsible for any property damage caused by this device. Use at your own risk!

Equipment List!

~ A hacksaw, or other saw to cut the PVC pipe

~ PVC primer and cement, to fasten the PVC together

~ A drill and assorted drill bits, to make the various holes for the fill valve, pressure gauge, etc.

~ A tapping set, for making the threads in the holes we will drill

~ A Dremel, or other rotary drill/tool and a sanding drum, to cut the muzzle cutter

~ An adjustable wrench, or an assortment of regular wrenches for tightening the various fittings on the sprinkler valve

~ A bike pump or air compressor (air compressor highly recommended!), to fill the air tank with...surprise! Air!

~ A pair of Vise-Grips, helpful for tightening different fittings, but also for holding the larger tapping cutter.

~ Teflon tape, for sealing all threaded connections

~ Epoxy, I used 5 minute epoxy, we will use it to seal up parts of the sprinkler valve

Materials List!

For the air tank-

~ 16" length of 4" PVC pipe (schedule 40 works great for all PVC parts)

~ 4" PVC end cap

~ 4" to 4" female-to-female PVC coupling

~ 4" to 2" PVC reducer

~ 2" to 1 1/2" PVC bushing

~ 1 1/2" to 1" female threaded PVC reducer/adapter

~ 0-100 psi pressure gauge

~ tire fill valve, like you would find on a car or bike tire

For the sprinkler valve-

~ sprinkler valve (duh!). I got mine from Amazon since I couldn't find one at any nearby hardware stores

~ 1/2" male-to-male compressor fitting

~ blowgun (the kind used to blow dust off things) with a 1/2" opening

For the U-connector-

~ 2 2" 90 degree PVC street connectors/elbows

~ 1 1/2" to 1" female threaded PVC reducer/adapter

~ 2" to 1 1/2" PVC bushing

~ 2" to 2" female threaded adapter

For the barrel-

~ 4' length of 2" PVC pipe

~ 2" to 2" male threaded PVC adapter

That's it for materials, so let's get started!

Step 1: Assembling the air tank

(air reservoir, if you want to be really technical)

So that you may better understand the way the parts fit together, I have made an exploded view of the air tank.

We will be working from the back of the air tank to the front, starting with the fill valve assembly, so first things first, we have to drill the hole for the fill valve. The final hole size will be 7/16", but to get a clean hole we will drill in stages. Before we start drilling the holes, we need to make a small indentation so the drill bit doesn't skate across the PVC. After you make the indent, use a 1/8" drill bit to bore out a small hole. Next, I used an 11/32" bit to enlarge the hole.

Our next drilled hole will be the final size of 7/16". I had a bit of trouble (I'm so phunny) with the bit grabbing the plastic too hard. Just go slow, and don't push on the drill too much, and you should be fine. I used a countersink bit to make the valve fit perfectly into into the hole.

After putting it into the hole, screw the washer and nut (in that order) onto the threads on the valve.

Now we have to glue the end cap onto the pipe, so get out the PVC primer and cement. First, use the primer to swab the inside of the end cap and the outside of the pipe. Do the same with the cement, then push the two pieces together and rotate the end cap on the pipe a quarter turn.

Next, we need to drill and tap a hole for the pressure gauge. The overall width of the threaded end of the gauge is 1/2", but the hole we must drill has to be slightly smaller to accomodate the threads we will tap, so use a 7/16" drill bit to bore the hole.

After drilling the hole, I used a 1/4"-18 NPT tapping drill to cut the threads into the air tank. I did not have a tapping wrench big enough to fit the tapping bit into, so I used (carefully) the Vise-Grips to hold it. The proper way to tap a hole is to turn the bit clockwise, then back slightly counterclockwise. Continue this pattern until the bit has traveled all the way through the material, then unscrew the bit.

Now we need to screw the pressure gauge into our newly tapped hole. Take the teflon tape, wrap a few turns onto the threads of the gauge and start screwing it into the hole. Once it gets hard to turn, use a wrench to tighten it as much as possible; we don't want any air leakage.

Great, we're almost done!

Now get the 4" to 4" coupler, because we are going to glue it onto our pipe (with the end cap, pressure gauge and fill valve already attached). Glue it on following the same procedure as before (swab both with primer, swab both with cement, push together and rotate a quarter turn). After the coupling comes the 4" to 2" reducer. Glue it onto the coupler. Next, put on the 2" to 1 1/2" reducer, followed by the 1 1/2" to 1" threaded reducer. You know the drill...

After you complete this, congratulations! You have completed one of the three main components of the air cannon! Next up, the sprinkler valve...
I built this following your design for the most part but added a few assecories... i thought that you might like pics of it as well... first time posting so lets see how it goes.
That looks fantastic! I think you created the tactical version of my air cannon! I like your use of the cordless tool battery. If you want to get more accuracy with the cannon, you may be interested in a rifled PVC barrel from the Spudgun Technology Center: http://www.spudtech.com/detail.asp?id=34. Thanks for sharing & keep up the good work!
Additions are the electric battery for the solenoid, shoulder rest, forward pistol grip, momentary action electrical trigger, and an iron sight.
I made it and it worked great it has a small leak but that is because I didn't put that much glue on it.
What can I do to make the barrell bigger?
You could add an adapter—maybe a 2" to 3"—right after the U bend going to the barrel. Then just use 3" (or whatever size you like) PVC pipe for the barrel. The other option is to add an adapter immediately after the sprinkler valve, and make the whole barrel and U bend whatever size you prefer.
I made it with my son. He wanted one for years. He built it for a school project on Newton's Law. It worked the first test, but the valve have way under pressure. You mentioned that spring in the valve may not be strong enough the pressure. Where do I find a stronger spring. Thank you!
Great news! I'm not sure the exact specifications of a new spring, but <a href="http://www.mcmaster.com/#compression-springs/=xmhozq" rel="nofollow">McMaster-Carr</a> would definitely be the place to start looking, as they have quite a few in stock. Good luck!
could I shoot other things like cement or glass?
it is time to put this on steroids. I am going to put this on metal barrel and use special carved ammo
<p>Yes, but I definitely wouldn't recommend it since launching glass/cement is so dangerous. As a general rule of thumb, if it fits down the barrel, you can shoot it.</p>
Here's what I'm thinking: (note: been planning to make a small paintball cannon) replace part of the barrel where the projectile is loaded with a slightly wider tube, and cut away halfway around the larger tube allowing for a shell to be loaded (may take some messing around with to keep air tight) allowing for a quicker and more convenient loading system
<p>Hey techwisperer: Great instructible! My question is why the U-fitting for the design? I'm looking to make a two shot &quot;hand cannon&quot; replica for my pirate show. I think I can get two barrels/tanks side by side (one to shoot a fake cannon ball, the other to fire confetti). Might you have any advice for making more SLIM holding tanks or for that matter a DOUNLE shot, DOUBLE barrel device? THX!</p><p>Check out my site: www.mypirateschool.com</p>
Thanks for your comment, and great site! The U fitting basically just makes the design more compact; some air cannons are configured with the barrel, valve, and air tank in-line. By adding the U fitting, my design cut down on the length of the cannon, and, I felt, made the cannon sturdier. I have heard that by forcing the air through the U as opposed to an in-line system, performance will decrease as the air will not have the same velocity. In my case, at 100 psi, the cannon will launch a potato VERY far (over 300ft), so I don't find it to be an issue. Your idea for a double barrel/shot device sounds interesting; while I'm not an air cannon expert, I may be able to help with a few tips. In order to bring down the size of the cannon, you could use a smaller diameter PVC pipe for the air tank(s) (keep the tank cylindrical). This would deliver a lower volume of air, thereby decreasing the power, but the tank should be able to handle the same amount of pressure as the full size version. If you intended the cannon to fire two separate shots, then the design would consist of two separate air tanks, valves, and barrels. If, however, you wanted to launch the confetti and cannonball simultaneously, it would be easier to have a moderately-sized air tank, and insert a Y fitting after the release valve, splitting part of the air into the barrel with the cannonball, and part into the barrel with the confetti. I hope this helps at least somewhat with your build, so thanks, and good luck! The Techwhisperer
<p>Danger: See link: This is not spam, but a warning. PVC will fail suddenly after a while. This was band member that hurt badly by a T-Shirt launcher explosion.</p><p>See the pictures and never use PVC to hold air, Please.</p><p><a href="https://fundrazr.com/campaigns/1Zs3c" rel="nofollow">https://fundrazr.com/campaigns/1Zs3c</a><br>..</p>
<p>I am DEFINITELY going to build this soon I have most of the materials right in our tool shed!</p>
One troubleshooting idea, sometimes the sprinkler valves spring simply isn't strong enough to hold back the first bit of air, and when you fill it up the air leaks out the barrel, solve this problem by simply getting another spring, one slightly stronger.
<p>Your pipe and several fittings are not pressure rated. I can tell. Please replace them.</p>
If you try this PLEASE only use pressure rated PVC. If it says DWV (Drainage waste ventilation) and doesn't have a PSI rating DON'T USE IT FOR COMPRESSED AIR.
<p>You are right.</p>
<p>You used drain waste vent pipe and fittings, do not use them. Don't use plastic at all, it will shatter and may kill you. Use metal pipe instead.</p>
Great for the 4th of July!
And saluting the DIY gods! ;-)
that's cool But can It launch t-shirts
Don't hit Maude Flanders!
As long as the t-shirt fits into the barrel, absolutely! You may also want to use a lower pressure (under 50 psi) to keep the t-shirts from shooting too far.
How much did this all cost?
I already had some of the components (the pipe for the air tank and barrel, the blowgun and the fill valve) so I can only give a ballpark. The sprinkler valve was $15, I think the gauge was about $7 and the fittings a few bucks apiece. So about $30 not including the straight pieces of pipe. Depending on the length of pipe you get you should be able to construct this for under $50. I know this isn't a very clear answer, but hopefully it answered your question.
I am totally making this with my dad!
Great, I'm glad you enjoyed it! I am working on a shooting video to show the power and range of the cannon, which should be up within a couple of weeks. Good luck!
nice l like it thanks for sharing :) l will be <br>http://tellaq.com
Really enjoyed your instructable. What's immediately apparent is your simple design and I like that. Some of the cannons I've seen are overkill ego-trips, or something :) <br> <br>A question: the PVC pipe you used - is the wall thickness standard for the different diameters of pipe or did you use extra wall thickness for safety?
Thanks! For both of the sections of PVC pipe I just used Schedule 40 pipe. It holds pressure well and is very readily available at any hardware store, but as I said on the last step, if you want to use pressures higher than 100 psi I would go with something thicker, or a pipe specifically made for high-pressure applications.
So clever.Young scientist/inventor has promise.
Great presentation and layout of steps
niceee...i've got to try this one!
Thanks, I'm glad you enjoyed it! Hopefully I'll be able to post a video of it firing sometime soon.
So, because I'm a cheap SOB, where would you peg the over all cost. Ive been thing of building a airgun like this one, but I need a ballpark so I can try to be fancy in places.
I was kind of winging it when I built this air cannon, so I didn't really keep track of cost. I know that it is under the $100 mark, however. What I did was look at some other designs, then sketched out how the parts would fit together. The most expensive component was the sprinkler valve at about $15 excluding shipping, but some of the parts (like the blowgun) I already had laying around, which kept the cost down.
Why don't you just use the solenoid valve already on the sprinkler valve?
Good question! You could definitely use the solenoid valve as-is, or even wire the solenoid in place of the blowgun, however, you would need three 9-volt batteries to trigger it. This would require you to build another small housing to fit the batteries, switch and wiring, and since the blowgun is simple and triggers quickly I chose this route. I am also not exactly sure of how the actual solenoid itself works, so it may not even work in place of the blowgun.
From what I understand the solenoid simply opens when you apply voltage so if you added a button it would be just like a trigger. I've seen quite a few compressed air guns pretty similar to yours on youtube and other places that just use the solenoid, I was just wondering if the blowgun worked better, or allowed you to only release a given amount of pressure at a time or something.
This is actually my first air cannon, so I have been working off of various online resources. What I have learned so far about pneumatic vs. electronic is that the blowgun does the exact same thing as the solenoid, but faster. Basically what happens (as I understand it) is when you fill the air tank, pressure on either side of the diaphragm equalizes (which is the hissing that you hear when filling it). This keeps the valve closed. When you trigger the solenoid or the blowgun, the pressure on one side of the diaphragm gets dumped out of the valve through a port in the solenoid or the blowgun, which causes the diaphragm to open and let the pressure out of the output of the valve. The faster the pressure on one side of the diaphragm is let out, the faster the valve will trigger, Which is why the blowgun is used for speed. I found this animation of a sprinkler valve in action also, which really helped me.<br> <div class="media_embed"> <iframe frameborder="0" height="315" src="http://www.youtube.com/embed/XfukXLK7jUU" width="420"></iframe></div>
Okay that makes sense. Nice instructable by the way, you got my vote in the redneck contest.
Thanks, I'm glad you enjoyed it!

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