Homemade Air Cannon - General

I built a homemade air cannon over the past couple of weeks (only about a day's worth of actual work, but getting the stuff took time) It's designed to shoot small objects like ping pong balls and it works pretty well. I've only tried pumping it up to 140 psi so far, but I'll probably look into getting a proper compressor and getting it up to about 200 psi. Here's a test firing of it when it's at 120 psi (there's nothing loaded in the barrel): [media]http://www.youtube.com/watch?v=0taF-HNM-qg[/media] Photo: [url=http://i.imgur.com/5m7bi.jpg][img]http://i.imgur.com/5m7bil.jpg[/img][/url] [editline]30th May 2011[/editline] It manages to shoot ping pong balls a surprising distance, so I might try filling the ping pongs to make them weigh more and hopefully fly further. I've already shot a fair bit of crap over the neighbour's fence :v:

So, is it just some pvc pipe and a quick release valve? [editline]29th May 2011[/editline] I was actually thinking of making a potato gun.

[QUOTE=aydin690;30130199]So, is it just some pvc pipe and a quick release valve?[/QUOTE] It's not even a quick release valve. Unless you're aiming for a super high performance cannon, a simple ball valve will do the trick.

Awesome. Always wanted to build something like this. On a note of ammo, tennis balls and pingpong balls never go very far, though. You should build a cork or styrofoam Sabot and use the sabot to encase a wooden or metal arrow (probably wood as metal would likely be very dangerous) Not exactly sure what kind of force your cannon would exert, but may as well make the most of it with a sabot type thing and actually shoot at some targets.

I've been using ping pong balls filled with water and they seem to go a fair distance fairly quickly. I calculated the exit velocity of a water-filled ping pong ball by looking at some footage frame-by-frame and it's somewhere between 108 km/h and 216 km/h. Here's some other footage of me firing it: [media]http://www.youtube.com/watch?v=XmaIiyZKyzg[/media]

I made one of these in a similar fashion but with a more ergonomic design and a smaller barrel. I shoot AA batteries with a single wrap of duct tape out of it. kinda scary cuz they're metal fucking batteries and they actually shoot really far if i want them to. I shoot at a piece of wood and the batteries get bent themselves so I can only reshoot them a couple times.

Try loading water under the ping pong ball. Be sure you hold it like you mean it though or it might knock you on your ass.

[QUOTE=RR_Raptor65;30182753]Try loading water under the ping pong ball. Be sure you hold it like you mean it though or it might knock you on your ass.[/QUOTE] Weren't you making a Pak40 or something? You should make a thread for that, greatest thread ever

[QUOTE=hypno-toad;30187226]Weren't you making a Pak40 or something? You should make a thread for that, greatest thread ever[/QUOTE] It needed oxy, that and I suspect the chamber was just too large for the propane to mix properly, it just ended up pooling at the bottom rather than mixing. I did get it to fire once but that was it, just lucky. If I were to make another one I'd make a small pneumatic autocannon out of steel or aluminum and just hook it directly up to an air compressor with a regulator to keep it at 100 PSI. But I'm more concerned with making muskets, they're easier to make and far more powerful.

[QUOTE=RR_Raptor65;30182753]Try loading water under the ping pong ball. [b]Be sure you hold it like you mean it though or it might knock you on your ass.[/b][/QUOTE] I wish I had checked this thread earlier :saddowns: I filled it up with water last night, pumped it up to 140psi and let it go. There was this massive recoil and the cannon flew backwards out of my hands and hit the deck I was standing on. Now the Schrader valve I use for filling it is bent and flattened while the cap on the end is smashed to bits. Going to have to make a trip to the hardware store today.

Idea: Set this up on a stand, and get exact angles for the cannon. Get paint filled waterballoons. You now have your very own paintball artillery gun. Learn tons of stuff about Calculus and Physics: You now have a instant science fair project about artillery tables.

Load some gelatinous goo into the ping pong balls, and then commence bombardment of your most hatred enemies! Oh, and great job!

Wait, air cannons aren't banned in Australia? [sp]yet[/sp]

Reminds me of a smaller version of the good ol' rock-it-launcher from FO3

This is pretty cool, I build a smaller spud gun just for fun. Mine was also air powered with a schrader valve, but I made my hole a little bit too big so you have to really pump the shit out of before the valve seals properly and starts taking air (otherwise it just leaks out). Next time I'd make a deodorant powered one just to mix it up. [QUOTE=Quark:;30373769]Wait, air cannons aren't banned in Australia? [sp]yet[/sp][/QUOTE] Of course they are illegal.

Here's a deodorant powered one I built with a mate: [media]http://www.youtube.com/watch?v=tzPEF2_RFPw[/media] They work surprisingly well. We shot half a spud about a hundred meters.

What do you prefer? deo or air? I like that you can choose the PSI with air but with deo the air to fuel ratio is a little random.

I made one using PVC pipe, hairspray, and a sparker from an electric grill. Hairspray works very nicely, it shot the potato quite a few blocks.

You can also make a very good igniter from a circuit board kit and a Stun Gun. I made one for my 50mm breechloader awhile ago and it worked extremely well. Simple to install too.

[QUOTE=r4nk_;30477764]What do you prefer? deo or air? I like that you can choose the PSI with air but with deo the air to fuel ratio is a little random.[/QUOTE] Air's more powerful of course, but hair spray/deodorant is so much more fun