Supercannon II - my new homemade water gun

[Ben]

I am working on the technological successor to my disappointing older homemade water gun. I designed that water gun around the theory that a tube will "suck" water from the bottom well enough. The water gun was very functional and got very good range (easily 60 feet or more), but it was not reliable enough to justify further testing. I never posted about my title for the water cannon - "Supercannon." The next one in the series will be Supercannon II.

I now am working on my piston version of the same cannon, as described at Soaker Media's forum and I believe here as well. This piston version will be approximately the same size, but will separate the air and water with a big rubber piston. The nozzle and valve assembly are the same ones used in Supercannon I. Everything else is brand new.

The piston is yet to be ordered, and should be ordered today or tomorrow given my memory and time available. The rest of the gun is complete but not cemented. More information will be available tomorrow.

Some people have been wondering why I have not been as active lately as I could be, and the reason is that I am working on another website. The website recently became essentially my property, and it was previously a very popular website. To finish up the website, I will have to dedicate a considerable amount of time, but please be aware that I am not leaving here! I check here every day. If you PM or email me and I am slow, please send another PM because I likely forgot while working.

[m15399]

I've been waiting for this

Won't the PC (pressurized section behind the piston) have to be extremely big to be able to push out that much water? I was thinking, if you used the same pressure, but 3/4" PVC pipe instead of 4", it might shoot a lot further (sacrificing MAJOR shot time, though). And what if the valve was instead put behind the piston? As in, a gun that looked like a douch but had a piston in the barrel and a nozzle on the end. Would that work better? It might make the piston have a faster velocity when the valve was first open, meaning the most pressure (unless it's CPS, it will decrease pressure as it fires) will be pushed out before before the valve fully opens. I was thinking of making one like that using 3/4" PVC.

Sorry that was not explained very well. It's a little hard to describe what I'm talking about. I'll post a diagram if you need one.

[Ben]

A diagram might help, though I believe I get your basic idea.

The main problem with putting the valve in the center as far as I am concerned is leaking. Without a valve in the front, turning the gun downward will let the water flow right out. I usually do not consider that option for that reason. I also do not feel that there will be a higher initial pressure with such a design because once the valve opens, the pressure drops to fill in the extra space.

[m15399]

Ya, I thought of the leaking. Just an idea. It probably isn't any better than the other way around.

[Ben]

No one has made it, so there's really no way to know for sure.

I'll be taking a picture tonight of the water gun with the old Supercannon next to it for comparison. This new water gun is nearly exactly the same looking except for the new pressurization assembly on the bottom. The new pressurization assembly is removable to allow for possible repairs to be made to the assembly and the piston. This also means that the system is upgradable and can be made into a constant air pressure homemade water gun if I ever desire that.

[m15399]

Sounds great. Have you tested it out yet? What exactly was the piston you ordered? And will there be a writeup?

[Ben]

Supercannon II is not completed yet. I'll let everyone know here as soon as the water gun is complete. Sorry if you got the wrong impression.

There will be an article written on the construction. I'll try to describe exactly how I constructed this water gun, though I cannot guarantee that everyone will be able to follow it. Most of the article will be about design features and why they were chosen. The water gun is very simple and I believe you already know plenty to duplicate it!

I designed this water gun to be easy to construct and fairly cheap, so hopefully people will be able to duplicate it. For example, previous piston water gun designs such as MrPukeOnYourHead's used big O-rings. We know that O-rings are hard to get a good seal with all the time. Reliability is a must, so I simply ordered an actual piston seal! That's even the category the seal is in at McMaster-Carr.

I'll get images once the water gun is complete. The piston has not shipped yet and should be here by the weekend.

[m15399]

Hmm, the largest size of "pump shaft seal" I see is 2". Is this the wrong category (I'm on page 3288)?

These would be a real benefit to homemade pumps! Except you have to order them online...

[Ben]

I wasn't looking at the "pump shaft seals" page, I was looking at the "piston seals" page as I said. If you scroll to the bottom, there is a "Fabric-Reinforced Buna-N Piston Cups" with an ID of 1/2" and an OD of 4" that I was considering.

[m15399]

Oh, I see. The Buna-N cups look like the ones from my FF... which I can't get back on correctly, so I have to use my Argon pump, which is a few inches short.

Keep us updated

[Ben]

The temperature has dropped, putting this project on a temporary hold. As I probably said too, I am fairly busy right now. This project likely will be completed the next warm weekend. This is what happens when you try to find time for water guns in the winter!

Until then, I'll be starting my newly expanded water gun physics guides. In these guides I'll explain most everything I know about water guns, including designs made for performance such as this one. Look forward to this guide, which should be the largest guide on our website, spanning several pages. This guide will be more like a section or column in size.

[Ben]

I never quite realized how many months have passed! Thanks for viewing this Some Guy and reminding me!

For a while I was somewhat mad that the piston seals I ordered didn't appear to fit perfectly because they appeared a little too large. The stupid thing with this was that I never considered they were meant to be like that. They're supposed to fit really tight. That's what makes them seal well in the first place.

So, this water gun will be completed as soon as I get my parts out of storage, buy some new PVC cement and good lubricant. Supercannon II will be done with good seals too. I'll be looking to smash all output and range records.

I've also worked my design so that it may be "upgraded" with a CAP system later on. That was one of the design features I considered at first to make this water gun useful. I think I'll do that once I get the money actually. Without the CAP system, you'd easily be defeated with only one extremely powerful shot if you used this in a water war.

[lord malak]

That sounds awusume! I wish you luck on this project

[Ben]

Just one trip to Lowes to pick up the right bolts are needed to finish this. I'm also considering ordering some industrial lubricant for it too. These shouldn't affect my hosting costs too much unless the price of lubricant and bolts rose dramatically in the past few days.

Hopefully when this is finished, we can see some great ranges and outputs. I'm not too convinced this would beat SuperCAP in output (which admittedly was actually 127X at 60 PSI - we rounded down and you also have to remember that it was affected by drop-off since we did output over the entire interval), but I think since it is the current theoretically perfect design, in range SuperCannon II will not be beat.

[joannaardway]

I await the range measurements.

And then I dread to think what it could do with glycerine.