Picture of Easy-Peasy PVC Water Gun

There are a handful of do-it-yourself PVC water guns on the internet.

This water gun is similar to other versions out there, including this one I shared a few years ago, but with a handful of new tricks to simplify the design and make it easier for people to duplicate.

If you make a few, let me know how it goes in the comments.

Thanks for taking a look!

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Step 1: How it works

Picture of How it works

This type of water gun is basically a large syringe. There are two main parts: the outer piece which is the barrel, and the inner piece which is the plunger, or piston.

On one end of the piston there is generally some type of seal, that acts as a round, watertight squeegie. This seal allows the piston to draw water into the barrel as you withdraw the piston from the barrel, and to force water out as you push it in.

The hardest part with this style of homemade water gun is the seal. If it's either too tight or too loose, the gun won't work. There are a lot of complicated ways to make an effective seal, but I believe I found a simpler way to get the same results, quickly and easily. I'll explain as we go.

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Helijin made it!8 months ago

Awesome design! I made six of these. I couldn't find an acceptable plug, except for one that was a reducer, so I used a 3/4" (slip) to 1/2" (threaded) reducer and threaded a 1/2" plug into it. It cost a little more, but the reducer gave me the lip I was looking for to retain the o-rings. All of the 3/4" plugs I found didn't have a lip on them or were hexagonal with minimal lip. I also used a 3/4"x1"x3/4" T for the handle. I really like the idea of using floss to adjust for the o-rings - it worked great. I got the o-rings at Lowe's - item number 0544 by BrassCraft or 1-1/8" I.D (1-3/8" O.D) x 1/8" Wall. This was the closest I found to the metric requirements in the instructions. One other thing for clarification, both the 1" and 1-1/4" PVC pipe is Schedule 40 (thick wall.) Thanks for sharing your design.

seamster (author)  Helijin8 months ago

Excellent work! Good job making it work with what you could find. That is the trick with this sort of project.

Thanks a bucket-full for the great tips and photos!

chestersgarage made it!9 months ago

Made a batch of these this weekend with my kids. Super easy! The 3/4" caps we found fit into the 1" pipe with the force of a hammer. Didn't have to sand/shave at all. I thought I could get away without using floss, but it's required to be able to draw water into the barrel. And we added pistol grips! :) Thanks for the great 'ible!

seamster (author)  chestersgarage9 months ago

Awesome! I like the angled grips.

I noticed a couple of ours stopped sucking in the water as well as when they were first made, so I had to add a foot or so of floss to readjusted the fit of the o-rings. Good as new! (Just a thought, in case yours do likewise after some use.)

Thanks for the photo! Glad you were able to make some.

ar_caver1 month ago

I've got to make one (or six) of these! How far do they shoot?

seamster (author)  ar_caver1 month ago

Pretty far! The stream breaks up and turns to mist at about 50 feet, I'd say.

johnstat0007 months ago

Looks like a lot of fun! Someone could make this out of cpvc and turn it into a homemade nerf gun!

renokid made it!8 months ago

I used a 3/4" pipe as the piston with a coupler on the end which allowed a 3/4" plug to go perfectly into the coupler and correct depth too, with this there is no need for any sanding down of the plug. This was my first run, and I plan to improve the shaft of the piston as it's 3/4" and slightly sloppy but works fine. It shot water over 40 feet.

seamster (author)  renokid8 months ago
Very cool, glad you were able to make one!
danpritts8 months ago

I couldn't find plugs that were the right size - one i bought was too big, and needed to be cut down. The other was too small and the o-ring kept coming off into the body. I ended up using the too-small size, and cutting a slot in the pipe to hold the o-ring.

To cut the slot, i used a hacksaw - the mini "handle" kind worked well. And as always when cutting PVC, doing it on top of the trash can to collect the sawdust helped a lot. A standard perpendicular cut worked well to start the slot, and then to widen it I held the hacksaw at about a 45 degree angle.

I used a 90 degree adapter as the handle, similar to Helijin's T handle. I think this worked better than an end cap would have.

The dental floss worked great, thanks for the tip.

seamster (author)  danpritts8 months ago

Good tips! Thanks for the comment and photos. Glad it worked out for you.

I've noticed on mine that the around the o-rings the vaseline has turned black, I'm assuming from the rubber breaking down a bit. Also I've had to add a foot or so of additional dental floss to each one to maintain a good seal. So they need a little occasional maintenance to keep working right, just like most things I guess!

bogie71299 months ago

My younger brother made some of these, enough for five male siblings. The one thing I remember about they way he built his that is different from yours is that he used a "T" on the handle end of it where yours has an end cap, to make it easier to fill and expel the water. Having used one of his in a water gun fight while floating down the river in a canoe, when some guy thought he was going to ambush us with a super-soaker, he was in for a huge surprise when I unloaded on him. What great fun! Thanks for this tutorial. I enjoyed it very much.

Might I suggest using white grease for the lubricant rather than vaseline? White grease has been used on car doors to keep them operating easily and quietly for many years. I don't know if this will work or not because I've never tried it, just a suggestion. I understand the conflict of using Vaseline and latex. I think that's the warning on the side of a box of condoms.

There's a clear silicone grease for car windows that might work well. I used vaseline since I had it handy. I don't think the o-rings I used were natural rubber, I bet they will be fine. If not they were cheap enough. :)

seamster (author)  bogie71299 months ago
You're welcome! Glad to share. I'll have to take a look at white grease.

Thanks for the thoughtful comment.
LYHTSPD8 months ago
I made one as a trial and plan on making the other 5. I had a hard time finding the right 3/4" fitting so I ended up doing what another user did. I could not find the adapter that had the round collar in the plumbing section. I did find it in the electrical conduit section. It is a 3/4" box bushing for nmc. I then used a 1/2" slip in pvc plug to seal the end.

Something else I had an issue with it not knowing how far too pull out the plunger tube. I used the purple pvc primer to mark a stop ring about 2" wide right next to the oring assembly. This lets the kids (and me) know when to stop pulling on the plunger rod before you pull the assembly apart.

Thanks to the OP for this fun ible!
seamster (author)  LYHTSPD8 months ago
You're welcome! Glad you were able to make one. And good work-around for the plug piece. I thought that area would require a little tweaking for most people, depending on what they can find in their local stores.

Thanks for the great comment and helpful tips!
thegannclann8 months ago


seamster (author)  thegannclann8 months ago
Excellent, that will help a lot of people. Thank you!
zacker9 months ago

cool... im thinking, make them from 3" and 4" tube with a 1/2" hole for the water to shoot you could put a fire out with them! lol Nice Job, thanks for showing how its done!

seamster (author)  zacker9 months ago

You're welcome! You could indeed put out a fire with that, or knock over a couple kids! Hmmm...

ThisIsSteve9 months ago

Nice job great instructable.

EmmettO9 months ago

I've built similar pvc guns, I was always worried about using petroleum jelly because I thought it might eat through the o rings. I tried mineral oil to limited success.

seamster (author)  EmmettO9 months ago
I had the same concern, but in the end I concluded it was still the best option. I have some lithium lubricant that's supposedly rubber-safe, but I wouldn't want my kids being sprayed with it, even in tiny amounts.

I tested these with some water based lubricant and it didn't work at all. I ended up just sticking with petroleum jelly, and figured I could replace the o-rings if/when they deteriorate.
jtalvy9 months ago

Nice job! I think I will make some for my nephews.

reddog779 months ago

Great idea! I would add a "T" connector on the end before the end cap, then you have a handle for easier operation.

jaret9 months ago

A cool idea would be cutting those large pool noodles and zip tying them on. Would make this project safer!

bogie71299 months ago

I had one of your older type water guns a few years ago. We went canoeing down the Blackwater River in northwest Florida one hot summer day and I took my water cannon along. As we rounded one bend in the river, there were a couple of baddies ahead lying in wait with their super soakers. They pointed them at us and starting trying to get us wet. I pulled my cannon out of the bottom of the canoe and let them have it. You can not imagine their surprise when I waylaid them using my water cannon. They were ready to throw their supersoakers in the trash can after I finished with them. What great fun we had, too.

As an aside, my brother who lives in Texas, made mine for me. He was using his on Lake Travis one day when some crybaby complained to a passing cop that he got soaked by some heathen with a water cannon. The officer took my brother's water gun away from him, saying it was a weapon, and that if he ever caught him using it again he'd arrest him for assault with a deadly weapon. Har de har har har. What a goober. Just so you understand there's goobers everywhere. Use of this type water gun should be judicious, be one your best behavior.

jgibso79 months ago
Very nice! I was wondering where the dental floss was going to fit in.... great use for it. I might try somthing like this with schedule 40 electical conduit. lots of differnt typs of fittings and connetors. you got my hamster wheel spinning...
seamster (author)  jgibso79 months ago
Thanks! Excellent, I hope that hamster wheel churns out some great ideas!
Mike48669 months ago

Great job! I've tried to make these before, they're great on raft trips, and always had trouble with the seal. Might I suggest that you make the plunger a couple of inches longer than the barrel to eliminate the pinch factor where the end cap of the plunger meets the barrel.

seamster (author)  Mike48669 months ago

Thanks! Good point on the pinch factor. I actually considered that, but opted to simplify things in order to get the most out of my material using the dimensions stated. This way there is virtually no waste, although we do risk a few pinched fingers.

Perhaps a more pressing issue is that they don't float. I didn't do it, but there's got to be an easy way to modify a pool noodle to slip over the barrel, for folks like yourself that would use these on boats.

Have you thought of using foam pipe insulation as a float? They're made to slip over pipe & some are even self-sealing so if you can find one exactly the right size, the adhesive can be used to stick to the barrel so it won't slip off. And they're cheap, 6ft for about $2.

I meant to say "... so if you can't find one exactly the right size..."

seamster (author)  pattiemelt9 months ago

I hadn't thought of that. But it's an excellent idea! Thanks, pattiemelt!

Maybe if someone gives it a try they can post a comment and share their results.

tlebsack9 months ago

Nice. How far will it shoot water ??

seamster (author)  tlebsack9 months ago

They shoot about 30 feet. After that the stream is pretty much just droplets and mist, but it'll still get a person quite wet!

NeightR9 months ago

This looks like a fun project that I will have to make. I'm just curious about the dental floss instead of Teflon tape. I almost have to assume you tried Teflon tape and it had bad results.

seamster (author)  NeightR9 months ago

I didn't try teflon tape, but I suspect it wouldn't have worked as well as floss. Dental floss has a few good things going for it in this application... mainly, it's cheap, sticks to itself, and allows for easily adding or removing bulk as needed.

blvdminss9 months ago
Great job.... These are going to be fun.
wpace9 months ago

I used to make these when I was a kid using shaped leather for the seals. Now that I have kids of my own I think I need to try to make some of these...O-rings seem much easier than shaping leather.

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