Picture of Build a Pneumatic Air Rifle
I have always enjoyed making pneumatic potato guns. There's always fun to be found with a gun that shoots anything you can fit in the barrel. So I've decided to post one of my more recent builds of a small caliber potato gun. This is technically my first instructable since my mini-fridge was just a slideshow, so please bear with me. Plus, I feel I have to redeem myself from that mini-fridge since it ended up all over the internet.

Generic Disclaimer: I'm in no way responsible for anything anyone decides to build/create/destroy with anything from this instructable. Don't even try to build anything related to this if you don't know exactly what you are doing. If you are unsure about anything in a build process with compressed air involved, seek help of a qualified individual or just don't attempt it at all. Be responsible and use common sense :)

A little background info.... The idea to make this particular gun design was kind of a spur of the moment idea. I had some small pieces of PVC laying around and an extra sprinkler valve so I decided to go at it with what i had(save some money too). Most of the potato guns I make are usually larger diameter barrels (1" - 4") but this time I wanted to go small with it. The diameter of the barrel I decided to use was 1/2" and the air chamber was 2". I wasn't sure how well this would perform but it seemed worth a try. I will try to be as specific as possible in the build process. If you don't like part of the design or have any feedback, please let me know. I do like to hear peoples opinions, good or bad.

Here's a materials list of the items I used in my version. Depending on the size you wish to build, this list can change dramatically.

This is not a complete list, these are just some of the main parts.

Main Materials:
1/2" PVC Pipe
2" PVC Pipe
3" PVC Pipe
2 - 3" PVC Couplers
1 - 3" PVC Cleanout with Plug
1 - 2" PVC Cleanout with Plug
2 - 2" PVC Coupler
1 - 2" to 1"threaded bushing
1 - 1" by 1" threaded pipe
1 - 24 Volt Sprinler valve
1 - 1" threaded to 1/2" slip Coupler
4 - 10" Hose Clamps
2 - 4" Hose Clamps
1 - Cheap Airsoft Gun
1 - SPST Pushbutton Switch
3 - 9 Volt Batteries
4 - 9 Volt Battery Terminals
Miscellaneous Pieces of Wood

You'll also need some pvc cleaner, pvc glue, expanding foam, liquid nails, and miscellaneous building tools.

Also, sorry if some of the pictures are crappy. The best thing I had to take pictures with during the first part of the build was a crappy cell phone.

Nightkilla1 year ago
Very nice. I am thinking of making something similar but with a steel pressure chamber with threaded end-caps.
ebaneser2 years ago
First may I say, kudos maximus!!! By far the coolest thing I 've seen in many many moons!!! At 44 there are few ooooohs and aaaaaahs left in the world but this one ROCKS!!! I sawa high end pellet gun on edgun this weekend (youtube) and figured never gonna happen on my budget. I have tim the toolman syndrom and imeadiatly thought bigger chamber fora buttstock and thinner copper tubing to fit inside an aluminum arrow (nerf style) and BAZINGGGGG. great 'ible. Now to figure out how to e plain it to my ever enduring better half. :))
dasadler3 years ago
When using the arrows, did you wrap anything around the shaft to fill the barrel? In other words, something for the compressed air to push against as it seems like the arrow just sitting there would not be propelled very far or with much force.
CaptPikel (author)  dasadler3 years ago
Yes. A single paper towel (the blue shop kind).
actually, i think cellophane tapes are good for wrapping around cylindrical ammo for a good seal. they are so thin that you can make the diameter very finely tuned to what you want. duct tapes are too thick, just an extra round and its too thick, one round less, it leaks pressure. Plus, cellophane and PVC doesnt have much friction just same as the paper towel right. Thus, there will be no need to retrieve the paper towel anymore, just find the ammo back and its ready to be shot again. less messy reload. There are ideas on the net to make rifled bullets because rifling the barrel is a tough work. more accuracy.
shingkai5 years ago
 Nice, but just as a heads up, pvc isn't very safe to use for storing pressurized air. It's not designed to handle air, and even if its rated far above what you're using it for, it's still not a good idea. The rapid decompression can cause micro fractures to form, which can eventually lead to horrendous failure (pvc shard shrapnel). ABS is more flexible and ruptures rather than fractures when it fails, so I'd recommend going with that. Looks great otherwise though!
ABS is a bad idea it not for pressure it would break rather easier.
 Yea pressure rated ABS is a lot harder to get, but ABS is actually safer. Even though it breaks more easily, when it does, the result is a split forming and the air rushing out. Because it's slightly flexible, it doesn't shatter like PVC.
abs is not safer. decompression at pressures used in amateur pneumatics won't cause micro fractures. It's a choice between having something that will rupture at lower pressures (which is sill very dangerous in hand held cannons) or something that will only fail if improperly joined or filled with much higher pressures than those achievable with with hand pumps or cheap compressors.
better no explosion than a less damaging one.
CaptPikel (author)  shingkai5 years ago
 This is very true. ABS is not readily available to me unfortunately. I have a place I can get PVC from about 3 minutes away from my home. I have never had a compressed PVC air chamber blow up on me luckily. Which is why I always recommend wrapping the air chamber in duct tape. I'm glad you pointed that out. My photos don't show it I believe, but I did wrap the air chamber in duct tape before installing it. I usually run a tight overlay about 3 times on air chambers if I use PVC (about 2 rolls of duct tape for a 4 inch by 4 foot chamber). The duct tape may not prevent an explosion but hopefully should keep the shrapnel down. This is theory as I don't want to really test that :)
 I noticed that and it should help, but I've heard of tests where 3" pvc wrapped in duct tape, denim, and placed in a 1/4" plywood box at 60psi resulted in pvc shards embedded in the box. Granted it was hit with a remotely triggered sledge hammer rig to trigger the failure, but still, it's pretty frightening.

Just an idea though, if you threw some metal hose clamp bands around the pressure chamber every few inches or so over the duct tape, and then another layer of taper over that, that might help prevent failure and minimize damage if failure does occur.
wewantska5 years ago
how much pressure does this valve hold with the electronic switch ? does it leak?

hey I was blown away by this and if this is really your first 'structable its totally awesome !!!!!!!!!!!!!!!!!!!!!!!!!
how would you make it to shoot airsoft bbs?
reaper755 years ago
 how much does it cost?
CaptPikel (author)  reaper755 years ago
I'm not sure of an exact amount since I had most of the parts already. It would greatly depends on what store you got the parts from. A rough guess would be less than $50. Again, it mainly depends on where you get the stuff from.
Nice first 'ible!! It's like a plain solenoid pneumatic but looks sophisticated... I like it! I never thought of using airsoft pistol grips. That would be something to try with the cheap guns at the cheap novelty stores, and use the actual mechanics for something like a nerf gun, idk. :)

A suggestion: did you use Krylon Fusion brand paint? I've heard (from boltsniper and others on nerfhaven) that it bonds well to PVC and doesn't chip. I've seen it at walmart.
Kaiven5 years ago
Good design! nice job!
dietpoop5 years ago
this is a very good looking gun, and great for the fact that its pneumatic even better, id like 2 see more