Water gun efficiency

Threads about how water guns work and other miscellaneous water gun technology threads.
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Silence
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Re: Water gun efficiency

Post by Silence » Tue May 12, 2009 8:58 pm

To be specific, using a bladder in this way means you'll have to seal off the chamber around the bladder. While still being able to access the bladder itself for maintenance. Near the water inlet, you'll need to craft a fitting that secures the LRT and is glued to the mounting for the outer case.

In contrast, with a piston, all you need is a tube.

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adronl
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Re: Water gun efficiency

Post by adronl » Tue May 12, 2009 9:34 pm

I guess I will have to build one to find out. I'll order the part I don't have today.

I see great potential with the piston but the inner walls of the PVC are not perfect like a pneumatic cylinder the cups are designed for is the seal indefinitely not going to leak or very little over time and Has anyone made a pre-charge piston gun

Also to what you were saying about replacing the bladder and fatigue how much fatigue was experienced with the SuperCPS and with the DR-3 how long does the bladder last. Is it better with inner tubes layered or some type of balloon layered.

Last yes I could design a way to easily service the bladder but I hate problems with threaded pipe but It wouldn't be too bad because it would only be maintenance not an every time you load pain.
Last edited by adronl on Tue May 12, 2009 10:13 pm, edited 1 time in total.

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Silence
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Re: Water gun efficiency

Post by Silence » Tue May 12, 2009 10:23 pm

Pistons are already used in water guns that use hand pumps, which is nearly all of them.

And I already pointed you to Supercannon II. It's not a pre-charger, so it doesn't need to store pressure for extremely long periods, but it does create a good seal. There will some effusion while you're pumping, but it's not a big deal. Put a tiny Schrader valve on each water gun and your users can give a pump or two every now and then.

Actually, now that I think about it, a bicycle tire analogy works fairly well. Then again, bike tires don't leak much faster when they're being used.

Buzz Bee Toys/Water Warriors recommend storing the water guns uncharged. It's probably a little safer; nobody keeps (or should) keep a loaded firearm in storage. On the other hand, airsoft pistols are stored with the pressurized canister inserted to maintain pressure on and lubricate the seals.

I emphatically would not store a pre-charger at 100 PSI. I'm not sure where to draw the line, so I probably simply wouldn't store it charged at all. Anyway, I recommend selling these with the expectation that (a) they're very safe and need only be topped off now and then with a bike pump, or (b) the user charge them every time.

The alternative, a rubber bladder, could still leak – balloons do, although they're made of thinner material. And replacing a rubber bladder as it wears or bursts could get tedious.

Somebody once suggested using a bag instead of a balloon for this purpose. I didn't like the idea at the time, but it actually makes some sense. I still wouldn't assume it's completely airtight, but at least a bag can resist wear and tear better. Bags are cheaper and easier to find.

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adronl
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Re: Water gun efficiency

Post by adronl » Tue May 12, 2009 10:34 pm

I thought about the bag idea too but it think it would pop out the nozzle once empty.

I am after a very good design for a pre-charge for it's efficiency it would never be stored at 100 psi my guess is you will have about 30-40 psi when empty and stored all you gotta do is force fill with an outside spigot.

Again has anyone made a homemade pre-charge gun yet piston or any other system. Where when filling the force of the water charges the gun generating pressure and fires to the last drop no pumping.

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Silence
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Re: Water gun efficiency

Post by Silence » Tue May 12, 2009 10:45 pm

Precharging and hose-filling are mutually exclusive. For the latter, get some ideas from the 2-liter homemade and you should be set.

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adronl
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Re: Water gun efficiency

Post by adronl » Wed May 13, 2009 1:03 am

Oh yeah Ben on the water efficiency when I was talking about hydrodynamics on a curve I mean that the farther you want the water to go the higher the volume of water and more power is need to project it and your pipe sizes increase.

I imagine it as a curve because at a certain point the numbers increase exponentially I may not be 100 percent accurate but it is not far from truth.

Also on a pre-charge I ordered the hose this afternoon I selected gum rubber because it is stronger and it came with thicker walls hopefully it will work as well as latex but with less fatigue

Oh yeah everything I make has a High pressure schrader valve that bolt together
Last edited by adronl on Wed May 13, 2009 1:14 am, edited 1 time in total.

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Silence
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Re: Water gun efficiency

Post by Silence » Wed May 13, 2009 3:35 am

I have my doubts about gum rubber...it may too plastic, not elastic. The McMaster-Carr website isn't very navigable but I did find this chart, which seems to confirm my doubts.

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adronl
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Re: Water gun efficiency

Post by adronl » Wed May 13, 2009 4:31 am

Funny that is exactly why I bought it because the SuperCPS and the DR-3 use latex rubber and we had talked about fatigue.

Also the pressure rating for the latex did not impress me a 3/4" ID with 3/16" walls has a max 25psi.

On the page that talks specifically about the gum rubber it says that it will stretch to twice it's length it didn't mention how well it expands but being just a bit tougher I have high hopes.

However it does have a tensile strength of 3000psi :D Also the durometer is 45A and latex is 35A both (very soft) Last the wall thickness is twice that of the latex at 3/8

It may or may not work but I will try and make it. Either way you get data.

What are your thoughts as far as efficiency goes and the nozzle laminator will it truely improve shot distance, does it take away efficiency or add it?
Last edited by adronl on Wed May 13, 2009 7:54 am, edited 1 time in total.

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SSCBen
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Re: Water gun efficiency

Post by SSCBen » Wed May 13, 2009 12:02 pm

I'm fairly certain that gum rubber will fatigue significantly faster than latex and not expand much, but you're free to try it.

Also, the stress in the tube will be much higher than the pressure so 3000 psi actually isn't very good as far as tensile strength goes. Not that it matters, as the tube will be generating the pressure through it's expansion.

adronl, you have many questions that would be answered by reading a large portion of our website. Stream laminators are an option when turbulence is a problem. Otherwise they could reduce performance or make no difference. I'd suggest reading this page: http://sscentral.org/physics/nozzles.html

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