SpudFiles

My friend that lives right next to me is wanting to make a water Ballon Cannon. We have been playing with those like big 3 man Water Ballon slignshot luancher kind of things, but he wants to make a Cannon.

His Idea is to have a 40" long 2" diameter Barrel, with a 20" long 4" diameter chamber. And he also wants to use a Ball Valve for the air realease.

We are going to make a lot of water ballons that fit a 2" diameter, so the fit well in the barrel.

I Don't really know how it wil work out. Should he use a BIGGER chamber? Becuase, His dad is a BIG TIME pool contractor, so my friend getting PVC extremely simple.

I think we might have to use wadding to protect the ballon from poping, or maybe the air will be to much on a water ballon.

What do you guys think? Bigger Chamber? Longer Barrel?

You will need alot of packing to cushion the ballon from the rapid acceration. If you don't, the ballon will burst and you will have some spray.

Well, to get any kind of distance, you'll need pressure, but the higher the pressure, the more chance there is of popping the balloon. To be honest, this is one of the few times I would suggest using a ball valve rather than a sprinkler valve or something like that. With the ball valve, you can open it a little more slowly, thus preventing the balloon from popping. In order to pull this off, you may want a bit longer barrel, to allow acceleration to continue. Other than that, it'd just be a matter of you figuring out how quickly to open the valve. I think you could pull it off.

i think about it too but i tought that the air will popping the ballon... good luck with that update here!

You should try making the barrel very long, like paaiyan said, but it probably won't be portable at all, so if you want something portable, stick with the slingshot (You can make your own out of surgical tubing from Home Depot, if you buy 30 feet of it you can make a really strong slingshot).

hey try this site.looks pretty cool.[www.balloonbazooka.com

Launchin water balloons is an extremely simple process; the only wadding you need is a small paper cup.

use something more durable... condoms?

why don't you just make a crossbow-like slingshot
(once you say "because...")
me: nvm then

Well, having been on watergun forums for even longer than spudgun forums, I have discussed these issues many times.

A modded sprinkler valve is still your first port of call here. Ball valves just don't cut it, ever.
At the very least, instead of needing 100 psi with a BV, you'll need half that with a sprinkler valve. No extra risk of popping balloons - in fact, even less - but half the pumping.
This will also allow a shorter barrel.

Plastic or paper drinking cups are excellent wadding for balloons in 2" barrels - with minimal breaks in the barrel.

@Cannoncreator: That is still a C:B of 2:1. That should be way more than is needed.
In fact, I might even suggest just using 40" of 2" for both the chamber and barrel - half the pumping again, but still most of the power.

I second everyone else's suggestion of using paper (or plastic) cups as wadding. In fact, you should use two cups. The first cup goes into the barrel with it's top towards the valve, the second goes in with it's top towards the muzzle. The balloon goes in the second cup.

The first cup is to seal the barrel, pressure from the valve expands this cup. The second cup is to keep the balloon from touching the barrel. With this setup there is much less chance of the balloon breaking. Indeed, if the cups hold together there is virtually zero chance the balloon will break while still in the barrel. (Though it may instantly disintegrate once it leaves the barrel if the velocity is high enough.)

Personally, I like the clear plastic disposable cups instead of wax paper cups since the plastic is much stronger than paper.

A 2" barrel is going to be pretty disappointing for firing balloons, a 2" balloon is really pretty tiny. And, clear plastic cups won't fit in a 2" barrel. So, I would recommend as larger ID barrel, 2.5" or 3".

I built one. Sometimes it would work and other times, the balloon would break in the barrel. I feel this was due to the friction created in the pipe. Also, I was launching 5 at a time (which was neat watching the balloons rain down). I made a complete sabot (using plastic cups as the wadding) and it works fine now.

ya, I think using a paper towel, to wrap the ballon would work very well, as long as it stays dry.

I just thought of this, but I don't know if it's viable... Take some 1 1/2" SDR-21, and cut it in 5 inch or so lengths. Wrap a few layers of paper towels around the balloons, and put them in the lengths of pipe. Use 2" SCH 80 for the barrel, and put some screws through the end, but only slightly. This is how it works. The air is released. The SDR 21, with the balloon inside, begins to move, but the SDR-21 weighs it down and doesn't allow the balloon to flex much, preventing popping due to acceleration. Once the SDR-21 catches on the screws, the balloon flies out of it. The part that makes it work is that the SDR-21 absorbs most of the friction from the barrel, but the balloon still experiences acceleration. This idea will cut down on the balloon's total exposure to friction over the entire launch. If this would never work, (I'm looking at you, joannaardway ) then just ignore this. I hope I've helped though!

It wouldn't work, because of how tight the fit would be. The gun would just shoot out the water balloon and pop it on the screws you put in the end of the barrel.

All you need to do to keep the ballon from poping in the barrel is keep it from touching the barrel. The G forces will not pop the balloon if it is supported from the bottom. Doesn't matter if it is accelerating at 5G or 50000000G it will not break.

Of course, once it exits the barrel, if it is moving too fast then air drag may rip it apart.