building homemade water gun

Build a homemade water gun or water balloon launcher and tell us about it.
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captianfear
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building homemade water gun

Post by captianfear » Wed Aug 27, 2008 2:24 am

I am building a water gun similar to a basic water cannon it has a shrader vaulve at on end and a vaulve on the other. I have seen ones like this. mine has a resivor connected with a vaulve. I read the aph guide and it said that the chamber has to have the pc have a chamber above so the air pushes the water out. Do i need this for my cannon. I drew some sketchs quickly. could you help me? sorry about the spelling, i was in a rush.Image Image

aEx155
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Re: building homemade water gun

Post by aEx155 » Wed Aug 27, 2008 3:20 am

First off, welcome to SSCentral, captainfear!

Second, a few questions so that explaining can be easier:

Have you built something already and want modification advice, or are you building something and want building advice?

Would you water cannon have a piston like in the Supercannon II?

You said that you read the APH guide; what other guides/articles have you read?

Lastly, are you planning on building an APH, a piston-pumper (pump to fire, no trigger), a "water cannon", or a Supercannon II gun?

Now that that's done with, some basic stuff:

Since air always floats above water, and you want the air to push the water out, you will probably always put a water outlet on the bottom of a pressure chamber (PC). The only exception to this rule is if you're using a piston or LRT.

IF you put a water outlet on the side of a PC and the water ends up below the outlet line (water isn't completely covering the outlet), then you'll probably end up with air escaping, which is bad for air pressure guns.

Lastly, something specific to your question:

Usually, anything with water coming out of it needs to be vertical or have some method of making sure the water gets to the outlet. In any case, vertical with water output on the bottom is best. That being said, if you're designing a "water cannon" that uses a piston, then adding a reservoir on the top will not work; you would need it to be connected to the water side only and it would have to be pressurized.

What this means is, if you built a "water cannon"/Supercannon II gun with your first design, it wouldn't work.

Please feel free to ask more questions if I'm not making sense (I tend to do that).

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CROC
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Re: building homemade water gun

Post by CROC » Wed Aug 27, 2008 3:32 am

Wow, even I almost got lost :p

Anyhow, the guns you saw were possibly Douchenators, or WBLs. You would need that tank as illustrated in the last image unless you want a mist shot most of the time.

Now, to some tech info:
Using a balloon pump attached to a check valve that is spring loaded (They cost a ton up here), you could use a pressurized reservoir type gun, but you would only be able to load it with a low pressure, unless a ball valve is installed on top of the PC.
-Croc
It's been a while guys, and its good to be back

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captianfear
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Re: building homemade water gun

Post by captianfear » Wed Aug 27, 2008 1:06 pm

i am not building a super cannon, im building basically just a pipe with a vaulve at on end and a tire vaulve on the other. i added two vertical chambers to my design. I am still designing the gun, i am building it asap. with my design you open the vaulve and fill the gun with water. I want to add a resivoir connected to the top of the gun with a ball vaulve connecting it.

aEx155
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Joined: Sun Apr 27, 2008 3:13 am

Re: building homemade water gun

Post by aEx155 » Thu Aug 28, 2008 1:50 am

captainfear wrote:I'm building basically just a pipe with a valve at on end and a tire valve on the other. I added two vertical chambers to my design. I am still designing the gun, I am building it asap. With my design you open the valve and fill the gun with water. I want to add a reservoir connected to the top of the gun with a ball valve connecting it.
Another question then:

How big is the "pipe with a valve at on end and a tire valve on the other"? 1/2", 3/4", or 1"?

Your design seems very similar to my homemade. Stripping it down to its basic design, it had a pipe with two vertical chambers (soda bottles), a valve on one end, and an air inlet on the other. Is this what you were planning?

Image

[If you haven't seen my homemade, that's what I'm talking about; air goes in through the bottom valve, the three soda bottles are vertical PCs, and the outlet/valve is on the upper right. It's not exactly a "pipe with a valve at on end and a tire valve on the other", but it's the same concept.]

If you were planning to add a non-pressurized reservoir to the pipe, say, before or after the vertical PC, then it wouldn't work. In order for water to travel into the PCs, you would need pressure; air from the tire valve would add pressure but not in the right place. What this means, is, that you would need a pressurized water source to fill your gun.

This seems very confusing to me now ( :p ), but hopefully you can make some sens out of it. If you don't get anything, though, answering my question above would help a lot.

EDIT: Thinking about it, if you are using 1/2" or 3/4" pipe, then this means that you design is an APH without a pump (or an air pump in place of the water pump.) Does this make more sense? (explanation wise)

A design like that would be difficult (if not impossible) to fill properly without a pressurized water source. Simply pouring water down the outlet valve won't work; water levels will get uneven, and when you try to pressurize it and shoot, then one might (most likely will) run out of water before the other and you'll end up with mist shots. If you do try this, I would make sure you've thought of how you're going to fill it before you build it.
Last edited by aEx155 on Thu Aug 28, 2008 1:58 am, edited 1 time in total.

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CROC
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Re: building homemade water gun

Post by CROC » Fri Aug 29, 2008 3:19 am

Just so you know, I copied none of this from any sites. The words just came to me, and I wrote them. This will probably be posted on Extrawater soon. (the parts for an air pressure water gun are similar to the article here on the site though)

Ok, so if you expect the gun to fire more than simply a mist shot, read further. If you wish to learn how the APH style of gun works, read the second part. For all of it, read the whole deal. I'm about to do an off-school lecture (Don't worry, I'm scared too)

To prevent just a mist shot and lots of left over water, you need something that will prevent the air from going through the nozzle. This is done by making the raised sections past the second check valve that we call pressure chambers. They prevent the air from exiting through the nozzle because the water will always be below the air. Therefore, in a properly crafted homemade, one should never get a mist shot. The larger the pressure chamber, the lower the chances of getting a mist shot are.

Now, how it works (I was going to post this whole post yesterday, but I lost the post on my iPod):

The gun functions by offsetting the common pressure in the gun. When the pump is pulled out, a sort of vaccuum is created, opening the first check valve, and filling the pump. Since check valves are only one way valves, the first check valve now blocks the path of the water. When you pump the gun, a small pressure difference between the area before the second check valve and the pressure chambers is created. This is impossible to maintain, so the second check valve opens to equalize the pressure inside the gun. Now the pressure is the same, and the air is forced up into the pressure chambers, thus increasing the air pressure in the gun. When the pressure reaches a certain point, the air can no longer be compressed. This is the maximum number of pumps for the gun. You then relieve the pressure by opening the ball valve to release the stream. Essentially, the ball valvle is a pressure relief valve, but it is the firing valve too.

For your gun to constantly work, you will need to have several things:
A pump
An external water supply
Pressure chamber(s)
Two check valves
A ball/trigger valve

Right now, your plans are for a water cannon that will only consistently fire a solid water stream at an angle of -45 degrees, which stinks for range (it would only be good for something like fortress defense.

If you have questions or need explanations of something, don't hesitate to ask. If I went over obvious things or stuff you already knew, don't worry. The whole point of lectures is to expect that the target audience knows nothing about the subject at hand.
-Croc
It's been a while guys, and its good to be back

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