Valve for firing water?

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
Lokoyo
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Sun Mar 01, 2009 3:51 pm

What would work better on firing water?

Ball Valve or Mod Sprinkler Valve?



How about on firing a water balloon?

Ball Valve or Mod Sprinkler Valve or Reg. Sprinkler Valve?
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Biopyro
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Sun Mar 01, 2009 4:26 pm

If you want to pire it at a person I'd go for a ball valve. A sprinkler will lack the flow you want unless you go big. Also, water being so heavy, it doesn't need a particularly fast valve because it spends so long in the barrel anyway.
If you want to fire anything else from the same cannon though, go for a sprinkler valve.
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btrettel
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Sun Mar 01, 2009 4:27 pm

If you're making a water gun, ball valves are the best simple valve. There's no advantage to using an extremely fast opening valve because the shot itself has duration. This is a very common misconception about water guns for people with a background in spud guns. However, if the duration of the shot is less than half a second a faster valve might help, but the valves used for spud guns could also hurt as I'll explain below.

Ball valves are the best because they are cheap, easy to find, do not present any flow restrictions, and don't introduce turbulence into the water stream. Sprinkler valves definitely restrict flow (in water guns) and will introduce a lot of turbulence into the stream.

As for water balloon launchers, I've been told all three options work fine. Extremely fast and high flow valves tend to break balloons from what I've read, probably due to the pressure wave popping the balloon or the friction forces on the balloon. I've read that even with a sabot the balloon will pop with a well made piston valve though so I tend to believe the pressure wave causes something wacky.

Generally you don't need range in the hundreds of feet so a ball valve should be adequate. As you're also (generally) shooting at people it's probably a good idea to keep the power low too so I'd suggest a ball valve unless you want greater efficiency.
Last edited by btrettel on Mon Mar 02, 2009 7:24 am, edited 1 time in total.
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Lokoyo
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Sun Mar 01, 2009 5:23 pm

Thank you very much :D

I currently have a 2" Ball valve (yes I know its huge but thats what I call for)
but the problemo is that its extremely tight so I need to figure out a way to lube it. I tried WD40 but that still didn't do the trick.

My only idea is to add an extended handle in order to get more force. Is there a DIY or how-to for that cause I saw it once but I forgot how it was made.
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covey12
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Sun Mar 01, 2009 9:06 pm

ive put water down the barrel of my simple ball valve, cannon, which is just a barrel, ballvalve, chamber stick cannon, and it works good. the water sprays out as more of a mist though.
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FishBoy
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Sun Mar 01, 2009 9:11 pm

I actually remember seing a beastly piston-watergun somewhere. *heads to google*...
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roboman
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Sun Mar 01, 2009 9:16 pm

Whatever you do, don't use a sprinkler to shoot water. Water wreaks havoc with sprinkler cannons, as demonstrated by myself. Just use a ball valve. However, if you shoot water balloons, feel free to use a modded sprinkler valve, as you will be able to shoot much farther.
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FishBoy
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Sun Mar 01, 2009 9:17 pm

Found it!!
This thing looks beastly

I'm not sure how it works, it might be some kind of coax though.
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inonickname
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Sun Mar 01, 2009 9:35 pm

Try petroleum jelly to lube up the valve.

I've seen that supercannon before, the valve handle/lever is a good idea.
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Lokoyo
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Sun Mar 01, 2009 9:35 pm

Roboman, thank you very much for the head ups. I am gonna work with a ball valve now :D but I just need to create the extension handle :O
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Daltonultra
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Mon Mar 02, 2009 2:55 am

Depending on how big you're going, a lever-arm globe valve may be the way to go. The valve itself is the same as a garden spigot, but instead of a knob, you have a lever that moves the seal. The big advantage is that you can use the lever trigger-style, and when you let go, it shuts off. If you drop it, you don't have to worry about it just spraying all over.

Look about halfway down this page, you'll see the valve in question:
http://www.mcmaster.com/#globe-valves/=tni15
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Ragnarok
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Mon Mar 02, 2009 6:08 am

FishBoy wrote:I'm not sure how it works, it might be some kind of coax though.
The most efficient method here would be to ask btrettel - considering the fact that you've just linked to his watergun. :roll:

However, that one simply works by having a pipe separated into two chambers by a moving piston - one full of water, one full of compressed air.
Basically, like a giant syringe - just instead of the plunger, the force is supplied by compressed air.

Simple, but powerful.
Does that thing kinda look like a big cat to you?
btrettel
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Mon Mar 02, 2009 7:35 am

I can't suggest globe valves because as I mentioned earlier, essentially all valves but ball valves would add turbulence to the water flow. Some valves are worse than others, and globe valves definitely as some of the bad ones. The turbulence can be minimized with what are essentially straws before the nozzle, but it's best to avoid that.

McMaster-Carr part number 46065K92 is something I believe we discussed at my water gun forum before which is an option if you want something you can pull to open. The pressure rating's fairly low but it is reported at 120 deg. F.

Rag described my Supercannon II water gun correctly. The basic idea is to separate the air and the water because water doesn't float on top of air. This essentially makes the gun a pneumatic syringe.

My primary suggestion would be to use pressure-rated components. You can see I used bell reducers. Replace those with pressure-rated 4 inch couplers and bushings.

Also, I believe my piston assembly could seal better with more rubber washers, but there's not any leakage problem so it doesn't really matter. I do occasionally find what I believe is condensation now in the air side.
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Biopyro
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Mon Mar 02, 2009 11:12 am

http://www.spudfiles.com/forums/backpac ... 14887.html
http://forums.sscentral.org/t5053/
Have a look at this. If you can get the parts at the same prices I did (low shop price) it's an excellent water cannon, because it runs off mains pressure so you don't have to pump it!
Those who would give up Essential Liberty to purchase a little Temporary Safety, deserve neither Liberty nor Safety. -Benjamin Franklin
cannon monkey
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Mon Mar 02, 2009 12:29 pm

I shoot water balloons from mine and I am using mod sprinkler.
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