Questions on 2.5 inch barrel tennis ball cannon

[Fnord]

Hmm, did the chamber actually say cellular core on it? That's the greatest concern. only those three fittings to replace otherwise.

Not sure of the regulations, but I found a piece of cell core pipe which specifically said 'NOT FOR PRESSURE' on it. Pressure rated pipe also says DWV, but there's a pressure rating near it.


I have not had a reason to upload this for a while, but please note that from now on DWVcat shall be the standard copypasta for advising PVC newbs on cannon construction

[Gun Freak]

how can you tell from the pictures, anyway?

They just look different than sch 40 fittings, typically more fancy... but anyway, replace that asap, I wouldn't use it above 50 because my friend had DWV blow up on his pneumatic at 60 psi, and with you doing this with your kids, that would be terrible...

Bottom line, get that replaced.

[MrCrowley]

how can you tell from the pictures, anyway?

They just look different than sch 40 fittings, typically more fancy

I think he was referring to the pipe, not the fittings

[jackssmirkingrevenge]

I have not had a reason to upload this for a while, but please note that from now on DWVcat shall be the standard copypasta for advising PVC newbs on cannon construction

Wouldn'tthis cat be a better warning

[Technician1002]

First, the tennis balls sure do fit tight into the 2.5 inch barrel. I was assuming they would slide right in. They really require a firm push to insert. No biggie, though.

The thin wall stuff is a much better fit for tennis balls. It can be hard to find, but it works very well. Loading is as simple as drop it in.
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[HunterT]

I have not had a reason to upload this for a while, but please note that from now on DWVcat shall be the standard copypasta for advising PVC newbs on cannon construction

Wouldn'tthis cat be a better warning

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This might be slightly more suitable for the Miniboy...

[High-PSI]

OK, I rebuilt the gun with all pressure rated PVC and a 125 psi pop-off valve. We have put dozens and dozens of shots through this thing. Man, I love this cannon!

I finally had a minor issue with my 2 inch Orbit valve [firing it at 110 psi ]. The valve uses a separated rubber sealing face from the diaphragm. This sealing face is pressure fit into a plastic mold that holds it in shape. Well, that rubber sealing face popped out of the plastic mold. So, I used some industrial rubber adhesive to glue it back in place. It has set overnight and I will try it out today. If this doesn't work, it would be easy to make a retainer on the CNC out of a 3mm thick piece of carbon fiber panel.

Anyway, I brought my compressor home so we could air it up at the touch of a button. So, we fired, and fired, and fired this thing. It is truely alot of fun using a cannon that can be fired (if very careful) in the public eye without the SWAT team showing up.

Now I just need to find some of that thin wall tubing for a better tennis ball fit and I will build a piston coax cannon next........

Matt

[High-PSI]

Hey Guys,

I was asked for some performance results.........

My sealing piston repair did the trick. We have been firing and firing and firing this thing. I have well over 100 shots out of it all the way up to 120 psi with great results.

At 50 psi, the hang time [fired straight up] is 15 seconds.
At 120 psi, the hang time is 21 seconds. At 120 psi, the ball is fired nearly out of sight.

I know this valve is not as efficient as a coaxial or a supah valve, but for our purposes, this thing is fantastic!

Anyway, my boys and I are having a blast (pun intended) with this thing.

Oh, lastly, I poures two cups of water down the barrel and fired it. Talk about KICK! It blew a wall of water a good 60 to 70 feet.

Matt