water balloon and snowball cannon

[ITman496]

Hi, I want to make a cannon to help me win snowball fights. Can someone recommend materials to make the cannon. I have used Google Sketch up to make a 3d model of the cannon. The images are in Photo Bucket.

Overview

Back overview

back

side

breach lock

air tank

front

air jack

valve open

valve closed


Comments will be greatly appreciated, thanks

ITman496

<content from double-post, edited in by SilentGuy>I will post instructions if any one requests. I just need to test it first...</content>

[Silence]

Welcome to the forums! That's some nice-looking modeling there.

You definitely will not want to use PVC. It loses strength in the cold, and has an extremely high chance of shattering.

Metal is probably the best option. It'll be fairly heavy though...but that's probably all the more reason to make the launcher small. You will want a small launcher to reduce the risk of dangerous projectile velocity.

A soft/dry/lightly-packed snowball will probably just break apart in the barrel from the blast of air (unless you use a sabot like a Pringles can; but the snowball might stick to the Pringles can). A hard/wet/solidly-packed snowball could kill somebody.

There might be some variations of PVC/CPVC/ABS that work better in the cold; I would go to McMaster-Carr to view the maximum rated pressures of some of those types at 0-20 degrees Fahrenheit, just to be safe. You'll want the maximum pressure you pump to to be half of the rated pressure, just in case you drop the weapon or something.

Still, metal is the best idea, as it isn't so brittle that it could shatter from a bit of pressure or from being dropped. It'll be heavy though.

[ITman496]

The metal is a bit to expensive, I will just use it as a water balloon cannon then... thanks


ITman496

[jzettel]

That is awesome. I have been looking to build a water balloon cannon just like it. Will you share your spec's and supplies. Thanks

[ITman496]

of course I will share the specs and instructions...

[humo16]

can you share the instructions because i would like to make a water cannon

[Silence]

The homemade section has articles about building your own water guns and water balloon launchers. The original poster here has been inactive for a while (look at the dates on the previous posts) so he probably won't see your response.

Edit: By the way, welcome aboard!

[cantab]

Snowball cannons could be tricky. I reckon they'll be even more fragile than water bombs, and as said, if lightly packed, might be literally blown apart by an air cannon.

So I'd be more inclined to use a mechanical/elastic launcher. Snowballs throw just fine, so I reckon they'd also work just fine in a catapult.
Of course elastic can become brittle in the cold. It all depends how cold things get where you live.

[aEx155]

Originally Posted by cantab

Snowball cannons could be tricky. I reckon they'll be even more fragile than water bombs, and as said, if lightly packed, might be literally blown apart by an air cannon.

So I'd be more inclined to use a mechanical/elastic launcher. Snowballs throw just fine, so I reckon they'd also work just fine in a catapult.
Of course elastic can become brittle in the cold. It all depends how cold things get where you live.

Technically, this would be possible if you think about how you do it:

If you used a tight sealing but (really) freely moving piston, you could put a compression spring on it and then something to hold the snowball; all of this could be inside something metal, to prevent fracture/breaking. That way, when air is introduced, it compresses the spring first, before moving the snowball. If you get a good spring, the spring would compress while pushing on the snowball; once compressed, there would be enough acceleration to keep the snowball together while the air accelerates it out of the barrel.

Yeah, it does sound complicated, but if you really want to launch snowballs pneumatically, you could do it that way. You might even be able to use this concept on water balloons...

[Silence]

humo16 was only asking about water guns or water balloon launchers, I think.

aEx: Are you talking about using the spring and plunger to make a sabot that doesn't pop out of the launcher? That would work, but there would be a lot of impact between the sabot and the stopper at the end of the barrel, unless you slow it down at the end, which would reduce the velocity of the snowball. Think of mangonels. They're small and efficient but they have to be built to withstand tremendous impact force.

Ultimately, wet packing snow should be fine in snowballs, even without a sabot. If you're using dry, powdery snow, it would break apart in the air anyway, even if it made it out the barrel in one piece.

Edit: A more durable method of having a reusable sabot would be a sabot on a string. The string is attached to a mount point on the outside of the barrel, somewhere near the muzzle. So it would be a bit like those novelty "pop" guns - you squeeze together the barrel and the piston, and a cork on a string pops out.

[aEx155]

Originally Posted by SilentGuy

aEx: Are you talking about using the spring and plunger to make a sabot that doesn't pop out of the launcher? That would work, but there would be a lot of impact between the sabot and the stopper at the end of the barrel, unless you slow it down at the end, which would reduce the velocity of the snowball. Think of mangonels. They're small and efficient but they have to be built to withstand tremendous impact force.

I was think to have a form of plunger behind the sabot, so the spring would push the sabot before the air did, to sorta ease up pressure on the snowball...

As for humo16:
The best place to look for water gun related building-stuff, it would be best for you to look in the Water Gun section of the Homemades are, instead of the water-balloon launcher section.