This Instructable will show you how to make a spud gun unlike any other before it; rather than using compressed air or combustion, it uses pressurized CO2 created by a chemical reaction to propel the projectile. This project is a very simple build, but it will require a bit of math and some chemistry.

Step 1: Materials

Note: you can use any size of PVC parts for this project. I just used 1/2" because it was available.

What I really like about this idea is that it allows for fairly precise and consistent pressure without having to use a compressed air system! I'd probably opt for a larger combustion chamber with a slightly longer barrel for more range though. I'm sure there's some way to modify it so that the sodium acetate doesn't gunk up the works, but the simplicity of this build makes up for the cleaning. Well done!
<p>Thanks a lot! The great thing is that you can use any size of PVC you have, so you could try larger pipe for more power. I only used 1/2&quot; because I had all the parts.</p>
<p>It would be interesting to see if there was a way to have the reaction happen in another chamber and just allow the CO2 to fill your pressure chamber before closing the back ball valve. You'd probably still end up with some liquid in the pressure chamber, but not as much. </p><p>I'd probably design it with a threaded end, two ball valves with a couple inches of space between, a foot or two of pipe, and then either another ball valve (for easy cleaning) or a cap. </p><p>First you open both valves and pour in the vinegar so that it fills the reservoir pipe. then close the second ball valve and pour the baking soda into the short pipe between the two valves. You could then close the first ball valve to keep as a backup charge for easy reloading, or screw it onto the back of the gun, point it straight up, open the second ball valve to drop the baking soda into the vinegar, wait for the reaction to happen, close the back valve on the gun and carefully unscrew the reaction chamber. I'd probably close the first valve on the reaction chamber too so that the pressure doesn't spray liquid everywhere when the chamber is unscrewed. </p>
<p>S=V==V============V<br> 1 2</p><p>S = threaded end, V = valve, &quot;=&quot; = pipe</p>
<p>This is an excellent idea! </p>
<p>how do you load in vinegar and baking soda?</p><p>Also you could use alka seltzer and water or vinegar!</p>
<p>I'm gonna try this...hopefully. It's awesome!</p>
<p><a rel="nofollow">https://www.instructables.com/id/Idaho-Howitzer/</a></p>
<p>I'm not sure if you did or not, but the use of couplers. Have you attempted that idea for the expansion chamber? I am curious if that would hold up to the stress and make for an easier cleaning of it...</p>
<p> I haven't tried it yet. My theory is that it will probably still make a big mess inside the chamber/barrel, but the smaller chamber would increase the pressure because the CO2 would have less room to expand. You could also use as much baking soda and vinegar that will fit, instead of using 50% of the chamber's volume. The only problem I see is mixing.</p>
very cool! nice to see an alternative that can also be more reliable.
<p>Thanks so much! It definitely is reliable, one time I left it for three hours and when I shot it later it was perfectly fine. </p>
<p>Never leave a loaded spud gun lying around, someone could get hurt! Only half kidding...</p>
<p>There was no dart in it and the barrel was off, I was testing for leaks.</p>
<p>Looks like a great project however I am apparently a bit slow in understanding the construction and if there are videos in this instructable they are not working for me</p>
<p>If the video isn't working, it might just be your internet. Try refreshing the page and check your internet. There might also be a problem with the embedded video, so click the YouTube button on the bottom right corner. Maybe YouTube is just goofing up, so come back later to watch the video. If anyone else is having a problem, please comment about it.</p><p>For the construction, it's mostly up to you. Cut a long section of any size of PVC pipe and then glue two ball valves at the ends. Glue a coupling to one of the valves with a small piece of pipe, and then cut a piece of pipe that fits in the coupling that's a similar length to the chamber. Are you new to working with PVC, or am I not explaining it well enough? </p>
<p>double plus good.....</p>
you're welcome! i have built several variations of spud guns, both air and combustion, may revisit and do an i'ble on the more reliable combustion one i built years ago.
<p>Sweet! It's awesome to see it shooting at different ranges!</p>
<p>Thanks! </p>

About This Instructable




Bio: I like the great outdoors, I play video games, and I have a knack for building stuff.
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