Picture of Easy $5 Water Guns
water gun3 006.jpg
water gun3 007.jpg
water gun3 008.jpg

Update! I've got a newer, upgraded water gun instructable right here!

It's a much better design, and easier to make. The original content of this instructable follows:

Recently I found myself needing a whole bunch of water guns. I didn't want to spend a lot of money, and I wanted ones that would be durable and last a long time. I figured my best bet was to just make my own.

I began by looking at a few places online, and right here on instructables for some ideas. I found the water mortar (part one and part two), and the waterzooka instructables very helpful.

With the basic idea of a piston/barrel-type water gun in mind, I wandered around the hardware store for a while until I came up with the following design.

I made a lot of these, and individually the guns ended up costing around $5. It'll cost you more or less depending on a number of things, of course.

They are tons of fun, and we get them out on a regular basis for family water fights. Thanks for looking. I hope you find this useful!

Remove these adsRemove these ads by Signing Up

Step 1: Supplies

Picture of Supplies

Conveniently, 1-inch PVC fits quite nicely inside 1 1/4-inch PVC. These sizes of PVC make up the barrel and piston sections of this water gun.

From one 10-foot length of PVC of each of the above mentioned sizes, you can make four 30-inch water guns or six 20-inch guns. The 30-inch guns are best for older kids and adults, whereas the 20-inch guns are easier for little kids to handle. Either way, the design is exactly the same.

This design is pretty simple and easy to mass produce. However, certain parts may be tricky to find. I had to check a couple of hardware stores before I found all the pieces to make this work.

In addition to the pipe, for each gun you will need the following:

  • One 1 1/4" PVC end cap
  • One 3/4" PVC plug
  • One 1 1/2" rubber washer, with inside diameter near 1/4" (and it must be real rubber, not neoprene)
  • One 1 1/4" fender washer, with inside diameter near 1/4"
  • One 1" by 1/2" 90-degree elbow, or similar (see below)
  • One 3/4" #12 pan head screw (or something similar that works)

I say "not neoprene" because common neoprene washers would not work for me. When I put pressure on the piston, water would just shoot out the back of the barrel. One of my local hardware stores carried real rubber washers which were a little stiffer than the neoprene ones, and these worked much better.

There are a couple of options for the 90-degree elbow, which will become the handle. I had plenty of 1/2" PVC scrap, so I got some 1" by 1/2" 90-degree elbows, and attached a small piece of 1/2" PVC to make the handle. You could use a regular elbow, or a cap instead, but I like the look and feel of the 1/2" handle.

1-40 of 43Next »
johntrev1 year ago
Great water gun; thanks for the plans! These were a big hit on our recent lake stay.
I've previously made the Waterzooka guns, but like the Easy $5 Water Gun better - this is a more straightforward design with easier to find and fewer parts, and a more manageable size. A couple suggestions/changes I made:

1. I cut the washers out of an old bike inner tube - they worked great, and I had a plentiful supply at a free to me price.

2. I tried a few different gun lengths, but liked 20" best - a manageable size with plenty of capacity. Keep in mind the whole thing will essentially double in length when you draw out the piston.

3. I wrapped electrical tape around the piston about 1" from the nozzle end, giving a warning not to pull the piston out any farther.

4. I used and liked a "T" fitting on the piston end

5. We lost 2 guns when they sank in the lake. Cap the ends of the T fitting on the piston to create an air chamber/ block water from entering the piston interior, sinking your gun.

6. Cut the barrel an inch or two shorter than the piston so that the piston goes all the way to the end of the barrel and expels all the water.
seamster (author)  johntrev1 year ago
Thank you for the great tips! I appreciate them and am sure many other people will too. Glad they worked out so well for you.
kbrunner1 year ago
Smart, maybe you should add a water tank for repeated fire.
rjs16171 year ago
I just left lowe's, they have all the parts including pre-cut pvc. problem is finding the correct o'ring. if you type in buna-n on the net a site pops up that has o'rings but I cannot decipher the proper o'ring. if you happen to figure it out shoot me back with a part number or actual dimensions please. still hunting myself and happy hunting to you.
16petero1 year ago
just wondering is this using schedule 40 pvc or pdr 21 ?
This one of the best things I've seen on instuctables! Hopefully if I can find the parts I'll make some this summer
seamster (author)  BobMarleyFan3 years ago
Thanks! I actually suggest taking a look at the waterzooka instructable, especially step #5. I've found that I like the simple building method in that instructable better than what I show here in mine. I made some water guns with O-rings similar to the waterzooka, and they have proven to last longer, and even work better than my version here. (If you can beat 'em, copy 'em!)
zoombaga4 years ago
i guess i'll give you credit for this because you posted it first >:( but anyway I was having a water fight with some of my friends and I was running down a sidestreet, and unfortunately dropped my gun and broke it. After QQing for a couple minutes I thought to myself: "what would someone on instructables do?"
so then (still in instructables mode) grabbed the pump from the end of my broken premade watergun and found a small length of pvc in a neighbors recycling bin
(shh! don't tell anybody!!) but with the pipe and the pump handle i just needed an endcap... fortunately for me I constantly carry a credit card with duct tape rapped around it, using a pen ink cartridge as a mold I put about a half inch of duct tape around it with a piece of paper in the center (to make the duct tape not stick to the pen cartridge) i took the small duct tape roll with a hole in the center and put in the front of my pvc pipe with the help of some more duct tape and there you have it. an extremely ghetto water gun...

btw i only said duct tape 4 times and sorry for any grammatical errors
superjoe124 years ago
I did everything you said but I dont get how the finished piston is supposed to fit into the barrel with the 1 and 1/2 inch rubber washer being too big for the 1 and 1/4 inch pipe
seamster (author)  superjoe124 years ago
The washer sort of folds down as you push the piston into the barrel. The fact that it's just a little bit bigger than the inside of the barrel is what creates a water tight seal. You will need to put some sort of lubricant in the inside of the barrel (like vaseline) to make it work properly. Let me know if you have any more trouble. I'll try and help if I can.
This still doesn't work for me after using vaseline. The piston just wont fit into the barrel because the rubber washer is too big. Should I use a 1 and 1/4 inch rubber washer instead?
seamster (author)  superjoe124 years ago
Can you take a clear photo of the piston end along with opening of the barrel for me? Post it here, and I'll see if that gives me a better idea of what the problem could be.
partymonsta4 years ago
oh mines way to small. i was wondering why u shaved it. lol
partymonsta4 years ago
my plug dosent fit snug it dosent even touch it. can u help or is that normal?
seamster (author)  partymonsta4 years ago
If it's too small you'll have to buy a bigger size.
ok. but does yours fit tight?
seamster (author)  partymonsta4 years ago
If we're talking about the plug that goes in the end of the piston--yes, it fits extremely tight. It's actually too big to begin with. That's why I have to shave them down as I show in step 3.
Meralis4 years ago
Awesome tutorial! Can't wait to make these with my husband. Any ideas on painting them? I thought Camo would be fun but wondering if the paint would just come off on the user's hands.
seamster (author)  Meralis4 years ago
I'd use spray paint. It might wear off after time, but I think it would stick pretty well.
For painting pvc, regular spray paint wont stck unless you coat with a plastic priming paint, you need krylon fusion(then he can enter it in the krylon contest too), sometimes regular paint will work if you coat it with a protectant but his best bet is to go with a plastic paint
seamster (author)  imthatguy11254 years ago
Hey, good tip. Thanks.
No problem, I had some issues when I was painting one of my potato guns, no matter what paint you use, make sure you sand the entire pipe to
Yandle Meralis4 years ago
Check this out for a paint idea
solsed4 years ago
how do you fill them quickly? is it a slow draw up through the nozzle or do you separate and fill and then reinsert the plunger?
seamster (author)  solsed4 years ago
I guess I didn't explain that. You draw up water into the barrel by pulling the piston back. You just can't pull it out all the way.
if you add a 1/2 inch pipeing on the end, its a vacume loading nerf gun. you can use yarn to seal it
Questor4 years ago
just remember, people . . . It's all fun and games . . . until someone gets wet then the water balloon hand grenades come out and the next thing ya know it's escalated to garden hoses who KNOWS where it will end slipNslides . . .water wiggles
99ottonero4 years ago
Awesome sauce with a side of cool beans!(bows down) i really bowed down! :P
profpat4 years ago
this good for a summer project!
dave3674 years ago
We've been doing these for years--both commercial and home made.

You don't really need the right angled handle; you're likely to brace the butt on your hip anyways (more range!), and if you push too hard on the right angle handle, it'll break. Saves a buck or two on the fitting, too.

Seals run the gamut, from rubber (as shown) to old-fashioned "leathers"--made of real greased leather (take apart a bike pump to see what I mean) to o-rings. O-rings are best, but require machining. You *can* do this by hand, with a small file. Chucking it in a drill and using a hand-held file works, too. We generally use 2" outer tubes, which, at 30" will hold about a quart of water. These are best used in pools or from boats, since the refills are nearer. ;-)

Capture The Flag is pretty fun, too. The "flags" are 5 gallon buckets--with trickling hose end inserted to keep 'em full--for filling the guns, of course!

If you get seriously fun, safety glasses are a nice thing, though if you hit them juuussst right, you can flip them off your opponent's face with the water stream. Harder to attack face/eyes if you wear a brimmed hat.

What I'm looking for now is a cheap and simple "laminar flow device" to increase range. In the meantime, chamfer, smooth and polish the "muzzle" hole to try to keep the water stream intact. If you make a bunch of guns, mark the ones with the best range, and make sure your "guests" get unmarked ones! ;-)
seamster (author)  dave3674 years ago
Wow! Thanks for the info. I was sure there were lots of people out there making something similar. As for the handles, I haven't broken any yet, but recently I haven't been including any 1/2" PVC on the bottom... but still using the elbow fitting. I like the ergonomic feel. What do you mean by "laminar flow device?" That sounds interesting.
See: Or if you're really interested, see: Dave
Would smoke-machines work in such a way?
cucumber2884 years ago
you are so cool, make a cheap shotgun water gun too, that really cool
Nerf gun makers and modders (like me) use 3/4 in PVC endcaps to fit inside 1 1/4 in pipe. It's not a snug fit, but just add some grooves around the endcap and hook on some appropriate o rings and attach it to a pushrod and voilà you got yourself a durable piston watergun. I'm pretty sure you can get more info about the endcap thing on nerfhaven. :) cool idea, at any rate!
seamster (author)  MadBricoleur4 years ago
I'll have to try that. Thanks!
LeumasYrrep4 years ago
I just made something very similar over this weekend that I am currently writing up the Instructable for. Yours are more friendly for the weekend DIYer as I had to use and engine lathe to build my piston. But with O-rings the ones that I made 2 years ago are still going strong.
seamster (author)  LeumasYrrep4 years ago
Thank you for the photo! That's pretty cool. I've gotten a lot of use out of all of mine. I figure if I ever need to, it'll be pretty quick to replace the rubber washers.
JohnJY4 years ago
Nice job! I like the idea, you could even have "Backyard Wars"!
1-40 of 43Next »