14 replies to this topic

[Zero Talent]

Anyone have access to anything this size, or slightly larger diameter (such as 2 5/16")? For the [smarter] metric kids, that's about 6.61cm or so.

I could just wuss out and use 3"ID pipe, but that's no good for seal, and I don't feel like throwing a foam collar around 355mL pop cans. I've been searching for something this size in the meantime, but my local hardware stores have become very limited in the past month.

I'm looking for any type of rigid plastic or metal pipe, so long as it's the given diameter or slightly larger, within 1/8" [3mm] or so. If anyone has any references, please toss in the name of the pipe, where you got it, and perhaps some specs: What it's used for, what colour it is, what company manufactures it...

If anyone has a reasonable facsimile (This particular pipe will be used as a barrel as well as shells, and thus does not have to hold constant pressure, so it could be constructed and glued from something, though I don't want to shovel out large sums of money or make a 25L boiling pool), please describe it, and any pros/cons you can think of for it. Thanks for everyone's help!

Also, if anyone has the type of pipe that closely fits regulation Tennis Balls on their mind, please note that; I'll be searching for it myself as soon as I snag some tennis balls.

[Well, I'm an idiot. Rather than 179/64", the actual measure is 83/32", which is 2.59375"... My face is quite red, I assure you. I would blame my spunky new calipers, but it takes a special kind of idiot to mix up 1/32" and 1/16" indices. Sorry about that. See the second post for any changes this makes.)

Edited by Zero Talent, 06 June 2004 - 03:57 AM.

[Vintage]

In decimals, your measurement is ~ 2.82". This website offers an ID of 2.815. I hope that's close enough. It is flimsy though, so you would need to secure it in 3" PVC.

So...you are gonna make a pop can launcher? Way awesome!!!!

~Vintage

[Zero Talent]

Sleeving 3" PVC supposedly produces a very close bore size, which is just fine for the barrel. Not so good for the shells on the turret, due to weight, so I'll be looking into the piping dimensions on manufacturers sites (such as Harvel).

Visipak would work fairly well, and I could get their "heavy walled" round PTEG, and triple-sleeve it, but minimum orders aren't so cool. I doubt they'd send a 4ft sample to an individual. Thanks Vintage.

Sch. 80 3" CPVC at ~2.864" ID, Sch. 80 PVC at ~2.864" might have to do... If I can even find it. I'll be doing a bit of research on local companies, I do believe.

Keep the info coming if you got it.

edit: Right, with the new measures, and after a swift kick to the face (I think I missed my mouth this time! ), the closest I can see is 2.5" SDR21 Harvel PVC at 2.581", or 2.5" SDR26 Harvel PVC at 2.635".

Now, I don't know any locals that offer Harvel PVC, and they don't seem the type to ship, but luckily, I noticed something interesting. All my own SDR21 pipe, made by Royal Pipe Systems (their site seems down, at www.royalpipe.com), is <= 1/64" smaller than theirs. My IPEX Schedule 40 stuff is an average of 3/128" smaller in ID than theirs. So, with hope, I may be able to find locally manufactured 2.5" SDR26 PVC pipe, with an ID reasonable close to what I'm looking for. The challenge is finding SDR26 pipe... I hear it's quite the challenge.
Armed with a phone and the Yellow Pages, perhaps I stand a chance.

Edited by Zero Talent, 06 June 2004 - 04:11 AM.

[Zero Talent]

http://www.geocities...ied/Brewfit.txt
http://www.geocities...d/Tennisfit.txt
http://www.geocities...ified/SDR26.txt

Visited stores out of order, still need the washers and the loading piston design. Praise be to small plumbing stores!

[Vintage]

Wow. Very nice. Have fun launching those pop cans up to your friends in sports bleachers!

You are gonna use that power for good, right?

[Hunter]

Ah crap, he's comming to VANS with a pop can/tennis ball launcher. I'm wearing my jock strap.


Nice fit, though. I'll write it on my list and look for some next time I go to a hardware store.

Edited by Hunter, 08 June 2004 - 07:03 PM.

[Zero Talent]

They take a suprising amount of force to blow up, even if shaken up first. Built really well. Shake one up and stand on it, see. Therefore, I'm going to need a lot of power behind this cannon for my purposes... Which, of course, don't involve hitting living things... Of course not... That would be a chimera of some sort of... Evil... We don't want that, do we? ...

But hey, if all else fails, we have 5 cent Nerf Grenades, right?

[nerfspecialforces]

If your making a tennis ball cannon, tape some Cambell's soup cans(the small ones) together. Works great.

[Alexthebeast]

They take a suprising amount of force to blow up, even if shaken up first. Built really well. Shake one up and stand on it, see. Therefore, I'm going to need a lot of power behind this cannon for my purposes... Which, of course, don't involve hitting living things... Of course not... That would be a chimera of some sort of... Evil... We don't want that, do we? ...

But hey, if all else fails, we have 5 cent Nerf Grenades, right?

Wait...the can are full when you shoot them? YOur gonna need to power that combustion style to get that much force, won't you?

[cxwq]

Never underestimate the power of air.

This thing launches full 20oz plastic soda bottles 300-400 yards at a 15* inclination.

Watch video number 6. It's a piece of 3/4" plywood at 60' range, 90psi. The soda bottle doesn't even notice it.

[Zero Talent]

Wait...the can are full when you shoot them?  YOur gonna need to power that combustion style to get that much force, won't you?

With the amount of volume I'm using in each shot, it's probably going to suck with full pop cans (about 50 or so feet), but that's not the point. Autoindexing is. I can always just fire tennis balls. As you can probably tell from the lack of update in this post, I'm still waiting on a ride to the hardware store for necessary washers.

Makes you wonder how much that air cannon cost, eh Cx? 6' of 6" PVC, with accompanying endcaps, couplers, bushings, and their minions coupled (sorry of the pun) with high pressure hose, and all the inner workings of the Supa Valves... Kinda scares me. $60 is certainly my limit on any gun... I'm quite sure that was much more.

Edited by Zero Talent, 09 June 2004 - 10:50 PM.

[cxwq]

I'd guess $200-300 in materials.

They offer a similar gun for $2000.

[nerfspecialforces]

Mine only cost about ten bucks, but I made it from some soup cans and a coke can duct taped together.Just poke a hole in the coke can, put in lighter fluid, shake, and light.

[Alexthebeast]

But Cx, you see those twin 6"x3' tanks? They are not at all practivcal for what zero wants out of it.

[Zero Talent]

But Cx, you see those twin 6"x3' tanks? They are not at all practivcal for what zero wants out of it.

I'm doing two proof-of-concept projects before undertaking the main one (Horizontal hopper-loaded Tennis Ball Launcher for the Equalizer valve system, small 6-shot revolver for the autoindexing mechanism), and I've learned a little from some calculations with the Tennis Ball launcher, which I'm currently working on. Just need to rack up some washers, and one 2.5" Endcap I forgot. It's going to have a 4' x 2.5" PVC (942CI) main tank, 82.6CI valve (Only ~60 of which goes to firing the ball), with only a 18.5" 2.5" PVC barrel. I had to go kinda cheap, because I wussed out and only bought 12ft of the 2.5" PVC I'm using for pressure chambers and tennis ball barrels in both cannons . Expensive, that stuff... I'll throw on a silencer to even out the aesthetics, but the barrel is nowhere near optimum length. No matter, I just want to get a feel for the valve. Besides, I'd like to keep this thing small enough that it's easily carried, aimed, and fired.
...Back to topic, though, this thing will only get roughly 3 shots before it drops below 90PSI, 5 before 70PSI, and 7 before 60PSI, from an inital fill of 100PSI. From 120, that's about 8 before it drops below 60PSI, so I'll be sticking around 100PSI for safety reasons. This means that, with the 18.5" barrel, the most this thing will get is under 100ft per shot PTG. Yeah, kinda crappy, but we'll see how I like this. Price you pay for semi-automatic.

As to combustion... Maybe another day. I never was much of a pyro.