need to build a waterballoon launcher

[Slauma]

As for your HPA paintball tank, do you know if it's configured for what's called a "high pressure" (usually 750-800 psi) or "low pressure" (usually ~450 psi) marker? Because you are unsure if it has a regulator I assume you do not have an external or adjustable regulator. Paintball HPA tanks much of the time come with preset regulators for HP or LP use. This regulator is in the tank valve itself (the part you screw into your marker/air system). Tanks configured for HP and LP use will both however still have to be regulated down further for use with PVC.

[clemsonguy1125]

I use plastic bags

[kydavies]

same here plastic bags are the best for water balloons because they compress slightly when fired and give the water balloon a genteler acceleration off the start and therefore preventing it from breaking

[killjoy_xt]

yeah i have used the wadding, it helps alot. here's my idea both the barrel and chamber are 2 inch pipe, only the barrel is ABS and the chamber is made of aluminum. if i pressurize the chamber with 2000psi how much of a barrel to chamber ratio would i need to launch the water balloon about 150feet (keep in mind the entire contraption would have to be no more that 1 and a half feet long)

[spudtyrrant]

yeah i have used the wadding, it helps alot. here's my idea both the barrel and chamber are 2 inch pipe, only the barrel is ABS and the chamber is made of aluminum. if i pressurize the chamber with 2000psi how much of a barrel to chamber ratio would i need to launch the water balloon about 150feet (keep in mind the entire contraption would have to be no more that 1 and a half feet long)

you can make a launcher that can do what you want, and conform to the size you want without using anywhere near 2000psi. I don't think you really how much power 2000psi is, it would be much more practical to use around 200psi, and even that may be overkill for what you need. i ggdt'd it and a 18" long coaxial cannon with conservative estimates will reach almost 1000fps with 2000psi, with a 3" chamber and a 2" barrel.

[killjoy_xt]

that very good news. and im using 2000psi only because my thank is roughly 3000psi of pressure and i don't feel like installing a regulator so if i just leave it connected it should pressurize the chamber to the same pressure as the tank (unless im wrong). what i don't understand is when i connect the bottle directly to the barrel(valve activated by screwing my compressed air bottle till bin activated the nozzle)why is it that it just plops out, does it really make a difference to have a pressurized chamber like medium?

[Technician1002]

Having launched water balloons, the sudden acceleration of a high energy launcher tends to exceed the stress limits of the water container causing failure.

It is best to go to a larger chamber, larger valve, etc for a gentle launch over a longer distance. Even eggs don't survive high energy launches. Use a sabot so the shape of the balloon is maintained during launch. Keep the balloon protected from high pressure air. It will rip them.

Think like you are building a water balloon slingshot. Gentle push over distance gets the momentum up to something useful. Hitting it with a baseball bat results in failure every time.