Introduction: Water Balloon Catapult

Picture of Water Balloon Catapult

Make a wicked cool catapult that shoots water balloons really well without them exploding right away! You can buy water balloon shooters in stores, but they never work well and explode the water balloon as soon as you let go.

Step 1: Gather Materials

Picture of Gather Materials

You will need an old towel, or some sort of rag that you can cut up. You will also need a length of surgical tubing, exercise tubing will work here as well. Lastly, you will need two small scraps of wood and some duct tape. You will also need scissors to cut the rag.

Step 2: Cut the Pattern for the Rag

Picture of Cut the Pattern for the Rag

The rag will become the pocket for the water balloon. It should be cut in a big "+" pattern. So, make a big 14" by 14" (it doesn't need to be perfect) square and cut out 3" by 3" pieces from the corners. You will want two of the tabs to be able to fold over the wood, so plan accordingly.

Step 3: Put It Together

Picture of Put It Together

Lay a piece of wood on one of the tabs. Then fold the rag over the wood and wrap the duct tape around it so the wood is stuck inside. Repeat for the opposite side and the other piece of wood.

Next, lay out the surgical tubing so that it runs over one of the other two tabs. Then curve it 180 degrees so that it runs down the other side of the rag. Once again, tape the rag over the tubing. Make sure you don't actually tape the tubing so that the pocket can slide freely up and down the tubing. Tape all of the corners and seams to reinforce them. You can not have to much tape on this project.

Step 4: Try It Out

Picture of Try It Out

Fill up some water balloons. Then, tie the ends of the tubing (they should both be on the same side) to a tree, pole, or anything else that is secured to the ground. You could also have a friend hold the ends. Next, have a friend hold the other side of the catapult, if you have a sturdy object close by, then you can attach it to that. Otherwise, the friend will do fine.

Next, set the balloon in the pocket and pull back on the handles of the pocket. Pull back as far as you can and let go! The balloon should fly pretty far. For best results, shoot the balloon at a 45 degree angle. If done right, the balloon shouldn't break and should fly pretty far.

For a better pocket, you can sew all of the seams with a heavy-duty zig-zag pattern. That will hold better and be more waterproof than duct tape, but the duct tape is much easier and quicker.


CreativeGeek (author)2013-09-23

You could substitute water for paint, mud, paste, or any other type of goop as long as it's harmless as well.

peppermintCreates (author)2012-09-09

I luv dis. (author)2008-07-07

insted of tubing could i just tie a ton of rubber bands togeter.

you'd need like a whold TON of rubber bands

DaNerd11 (author)zaro123452008-07-07

na, that prolly wouldnt work, unless you have reeaally good rubber bands theyre prolly gonna snap pretty fast, i made a slingshot about 6 ft tall that shot pebbles about 150 ft using rubber bands, they snapped after 50 uses or sumthing like that, so i dont suggest it.

jschap1 (author)DaNerd112012-08-03

I'll bet bike inner tubes would work well.

slimguy379 (author)2008-07-06

where do yo get surgical tubing?

some ace hardware stores carry tubing like this. or medical supply stores may as well.

do you mean like this kind
i know it says latex hose however it's really latex tubing.remeber this is for constructive and reponsible use

yeah thats it. very useful stuff

sory24712 (author)slimguy3792008-12-25


slimguy379 (author)sory247122008-12-25

thank now i know what one to get it from, thanks

sory24712 (author)slimguy3792008-12-26

no problem

ShNitZulll (author)2011-06-08

@backyardpyro217 that's because, assuming that they launched the balloon at less than the balloon's terminal velocity, the balloon would be going roughly the same speed at which it was launched when it landed.

dsmith1 (author)2011-06-07

Instead of the rag and duct tape pocket to hold the water balloon in, i used the top half of a coke bottle, and just roll the cut edge to stop the edge cutting the balloon and it strengthens the cup ring to attach the bungie cord to. Drill holes through the threaded end and thread a some cord through it to make a loop to pull back the balloon cup. These work awesome.

alex4646 (author)2010-05-30

sorry to get technical on you but this is a slingshot, not exactly a catapult

fozzy13 (author)alex46462011-06-06

Haha my thought exactly!

adamnsmith (author)2011-05-31

can it shoot more than water balloons... like fire crackers?

what about grenades and molotovs? MUAHAHAHAHAHAHA! i actually know a guy who made this with a few of his buddies, they were able to launch a water balloon about two blocks and still take out a window XD

CosmicBrambleclaw (author)2011-05-18

Wow that would sting like heck if it hit somebody

tracerb123 (author)2006-06-15

That isn't a catapult. That is a slingshot. A catapult would be something like what you see in medieval times movies.

trebuchet03 (author)tracerb1232006-06-15

a slingshot is a type of catapult (which they don't mention in the movies) ;)

Aircraft carriers use catapults to launch planes... Some roller coasters use catapults (just about anything that adds momentum without a chain lift)... A trebuchet also happens to be a type of catapult... Even a crossbow is technically a catapult :P

smurfsahoy (author)trebuchet032008-07-06

It doesn't say in those definitions (they are somewhat cursory - although the princeton one alludes to this by saying a "heavy" engine), but generally catapults have to not be handheld devices, so not a crossbow (which agrees with our gut feelings that a crossbow is kind of a silly thing to call a catapult - and also the fact that nobody ever calls them that in practice).

why are we even haveing this arguement. it dosent matter what you call it it still works the same.

intoon (author)tracerb1232006-06-16

I guess you missed the big discussion on this matter last month. A slingshot is something that you swing around (i.e. David and Goliath) and release shot out of. What we call slingshots are actually types of catapults.

Ironstar (author)intoon2008-07-06

Actually...the david and goliath story used a SLING, which was simply a pouch at the end of 2 cords... similar to the slingshot, but still quite different. Sling: Pouch, 2 cords, uses whirling action for propulsion Slingshot: Pouch, 2 rubberized cords connected between the pouch and a forked shape, uses stretchability for propulsion.

smurfsahoy (author)Ironstar2008-07-06

Too true. Also, both slings and slingshots typically would be handheld too, making them not catapults. Since this is tied to a tree, it probably qualifies as a catapult (though possibly still also a slingshot. The two can overlap)

Olaf One-Brow (author)tracerb1232007-11-26

So true, so true.

austin (author)tracerb1232006-06-16

depend on where you are a catapult and slingshot vary in meaning in britain versus U.S.

everyones a chump (author)2008-07-09

I have a store bought one, and it works fine, never had any problems with it. Also, if you tie one end to something, in my experience with multiple launchers, there is a good chance that the balloon won't leave the pouch and will come back at you. I highly recommend having to friends hold the ends of tubing much better and actually safer.

depends on the friends especialy mine.

King Crab (author)2010-02-10

I have a feeling that if I told my friend to hold one end, he'd either get pulled over when I pull back, or he'd just let go and I'd go flying back. Either way, it would end badly.

johnlin118 (author)2010-02-10

how did this get so dirty?

popa27272 (author)2010-01-31

im building a balista for a phsics project too this will be alot of help because i was wondering how to keep the pocket open

payount_slay (author)2009-09-18

this is gonna be fun can u use a huge rubber band that can stretch 2 like 20 feet

payount_slay (author)2009-09-18

dude this is sweet now i can shoot my 2 sisters thanks man

Matrix-technician (author)2009-09-15

AWSOMENESS!!!!!! I wish i had one of these to soak my buddies!

Mine! (author)2009-03-06

Sweet! I think I'm going to try it... MWAHAHAH!

mikesty (author)2006-06-15

Not bad, but I'd definately mount either end of the tubing to a pair of trees or posts. Maybe it's just because I don't really trust my friends. Or maybe I don't have any? Where did you get the surgical tubing from? Regardless, I'd like to order 50 of these and have them sent over to Iraq :)

soapdude (author)mikesty2008-08-15

i just recently bought surgical tubing at a medical supply store the common in mini-malls.

smurfsahoy (author)mikesty2008-07-06

If you tie it to two trees, it significantly limits where you can aim the thing at. A friend can move around so that the pouch is always right in the middle of the tubing, for a clean shot. Also, what would you use them for in Iraq? In WWI, people used to throw hand grenades with catapults, but that was made obsolete by mortars.

trebuchet03 (author)mikesty2006-06-15

My local Home Depot Sells it :P Its in the isle that has other plastic tubing...

intoon (author)mikesty2006-06-15

I just had the surgical tubing lying around. Exercise tubes will work too and can be easily found at any sports store.

thegunthing (author)2008-03-11

nice job. i might try to make one out of bike tubing instead of surgical tubing.( you cay attach this between 2 trees or poles if you need some "alone time"

drummonkey92 (author)thegunthing2008-07-09

hey, did you make one out of inner tubes? was it any good? i've got sum lyin around so it would save me money if it works well

bumpus (author)2008-07-08

I made one of these a while ago, and last week I reluctantly let my accident-prone friend try it out, he pulled it back, let go, but the balloon didn't go out, instead it shot backwards and hit him in the inner thigh, instantaneous bruise it was hilarious

bowmaster (author)bumpus2008-07-08


emac (author)2008-07-06

this is cOOOOOLLL good instructable tooooo

littlewit (author)2008-07-06

very cool

thermoelectric (author)2008-07-06

Good, but basic I love it.

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