Brog.- Super Soaker problem

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brogdenlaxmiddie
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Thu Jul 03, 2008 3:00 pm

Ok guys, while on a plane to London from China, I drew up some plans for a new super-soaker water gun due to the extreme heat in North Carolina (Home). I was going to have an over under style gun in which the upper barrel will have a piston that will have a guide rod. There will be a QEV (or something of the sorts) that will release the air from the bottom and push the piston which then pushes the water out. I was going to have a direct hook up to a water hose on the front and then a quick connect to the air chamber.

Problems:
~1~ How could I get the piston to come back? (It would have all the air behind it and no release)
~1 A~What would be a good compact, clean way of doing so?
~2~ Would I have to worry too much about the piston's guide rod rusting?


Ideas/solutions:
~1~ Maybe a release valve around the output of the QEV (small ball valve)
~2~ I was thinking about using an aluminum rod.


Any other ideas/comments are welcome. I'll get up some pics when I either get to a PC or a scanner.


Thanks guys! -Brog.
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POLAND_SPUD
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Thu Jul 03, 2008 3:59 pm

is there any advantage of this piston diea over a more traditional design?

one way or another pressure is acting on water forcing it out of the gun, am I right ?
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STHORNE
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Thu Jul 03, 2008 4:04 pm

this is what I think you could do for re-setting the piston.

just put a quick connect nipple with a ball valve (circled in red) at the end of the piston assembly near the nozzle.

and as far as the guide rod rusting, you shouldn't have any worries if you give it a good coat (or 8 ) of varnish/polyurethane before you assemble the gun (it acts as a water-proofing agent).

hope i helped.
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brogdenlaxmiddie
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Thu Jul 03, 2008 4:09 pm

Good ideas, but Poland Spud- what is the "regular way" and Sthorne- Good idea but why would you need the quick connect?

I understand that this topic may seem confusing but I really have no idea of a way to put it online right now since I'm on a Mac and don't have a printer/scanner.
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Brian the brain
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Thu Jul 03, 2008 4:35 pm

Just use a tank on top and a blowgun as your trigger.Use sufficient pressure and you will beat a store bought soaker hands down...
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POLAND_SPUD
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Thu Jul 03, 2008 4:36 pm

a traditional design looks like this ->>> (pic)
[sorry for the quality of my drawing] :roll:
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Brian the brain
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Thu Jul 03, 2008 4:40 pm

Don't forget to NOT tape a lighter at the nozzle...cough...ahummm


Why do I always get that feeling when people want to build "supersoakers"
brother361
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Thu Jul 03, 2008 5:04 pm

just take a fire extingusher and empty it out and clean it well
then istall a shrader valve at the bottom and fill it up with water then pressurize
voila a water gun
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psycix
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Fri Jul 04, 2008 6:49 am

1-A BV.
2-Why do you want to use a guide rod?
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brogdenlaxmiddie
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Fri Jul 04, 2008 3:24 pm

psycix wrote:1-A BV.
2-Why do you want to use a guide rod?

1- Sounds good
2- Thought it would be neccisarry since i want a kinda light piston thats going to be pushing a lot of WATER ( :wink: ) and I may be wrong about needing one.


BTW- Back in the States now and Happy 4th!
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Fri Jul 04, 2008 7:05 pm

I think he wants to build a type of water canon, a kind they have at Schlitterbahn New Braunfels. It has a barrel, that has water flowing into it. Behind that, is a large piston actuated by an electronic trigger. It launches a near coherent ball of water, that has quite a bit of force on impact. They are really cool, but they seemed fairly complicated, not to mention prone to malfunction. Thankfully, there was a button on the bottom to clear a jam.
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DYI
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Fri Jul 04, 2008 7:30 pm

You might have to start worrying about some of the finer details right now, that'll kill any watergun before it's even worth the money to get water to test it with.

The main problems I found on my water gun were lack of flow, lack of pressure, and a nozzle that doesn't work properly.

I was pressurising from a nitrogen tank through a 1/4" hydraulic quick connect, so the flow problems are understandable. The flow wasn't constricted in the system until it was supposed to be, but the propellant gas couldn't refill fast enough to keep up with the flow through the nozzle.

I could only use 150 psi or so, because that's what the hose was rated for, and I didn't want to risk bursting it and being drenched with "water". You're going to need more pressure than that if you want any decent range, probably 250 psi or higher. This means stronger hose, which is expensive in larger sizes.

Using just any old flow reducing part you can find isn't going to be the greatest for keeping a coherent stream, especially at higher pressures. It'll just spray everywhere, and that isn't good at all. Get a proper premade nozzle, or machine/cast one yourself if you want any kind of decent range.

Also, using an oxidising propellant gas in a watergun is a very, very bad idea, for (hopefully) obvious reasons.

Good luck with your watergun, and make sure you don't use it near any dry, wooded areas. :roll:
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brogdenlaxmiddie
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Fri Jul 04, 2008 8:13 pm

Alright guys.... seriously, it's gonna shoot H20. Nothing else....




yet



And DYI- in regards to low pressure behind the gun, thats the point of the piston. We all know how fast some guns can shoot things (BTW- I shot 1/2" rebar through 3/4" plywood today :D ) so I want the air to push the piston forward and just completly flush the system and put out a ton of water fast. Thats what I needed help with, a retraction system to push the piston back somewhat fast that won't interfer with the speed of the piston pushing the water...
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Fri Jul 04, 2008 9:05 pm

If you want to make a water gun with a piston to separate the air and water, follow this setup: http://www.sscentral.org/homemade/supercannon2.html

No guide rod is needed. The piston stays aligned because it consists of two piston cups.

To return the piston to its original position I used a simple ram rod. You'll need a valve to shut off the air supply and vent the chamber behind the piston but aside from that it's straightforward.

I would not suggest something like QEV. That'd be excessive and too expensive for a water gun. A simple ball valve in front of the nozzle is best. Opening times matter significantly less because the shot has duration. Ball valves impeded flow the least and do not make the flow more turbulence (or make it minimally more turbulent). You also won't have to worry about water dribbling out if the angle is too low with a valve in front of the nozzle.
brogdenlaxmiddie
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Fri Jul 04, 2008 9:13 pm

Thats similar to what I am planning. But, I probably won't use a QEV, more likely a Sprinkler valve with some elbows. A faster valve would help me in my case. Also, I would like it to be somewhat "advanced" so that when neighborhood kids want to play water-gun war, they will respect it more. Thanks though!
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