Homemade Water Guns

With the advent of the Super Soaker, retail water gun makers have been in an arms race to see who can build the biggest, wettest water gun possible. This race has not been missed by DIY enthusiasts, who have tackled the problem of creating a water gun capable of leaving the retail versions drenched. Making your own water gun is easy, but making your own water gun that makes the targets run away at the sight of it requires that you know a bit about what makes a water gun work.

Water Gun Basics

Every water gun works on the same basic principle. You generate pressure in the gun and then use that pressure to push the water out. To do this requires that your gun have four primary parts, a reservoir, a pump, a pressure chamber and a trigger valve attached to a nozzle.

The reservoir holds your ammo, the water. It’s basically a water tank with an opening that seals anda connecting outlet to run water to the pump area. The only limitation to size is how big a tank you’re willing to carry. Your reservoir can be a part of the gun or attached via hose depending on your design.

The pump is responsible for moving the water from the reservoir into the pressure chamber. Most pumps utilize a sliding plunger and rod setup within a tube. The tube connects the reservoir with the pressure chamber and works by creating a vacuum that draws water from the reservoir and then pushes that water into the pressure chamber. To keep the water from flowing in the other direction, your water gun should contain a one-way valve that can seal off water from flowing in any undesired direction. If you’re going to be creating very high pressure for your water gun, you may consider adding a pressure-release valve to the system so that the pressure won’t cause your pressure chamber to rupture.

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Your pressure chamber stores the air pressure that shoots the water. It’s important that you make the pressure chamber as strong as possible, using heavy materials, as this will allow you to operate a gun with much higher pressures, shooting larger streams of water farther. It works when the air filled pressure chamber fill with water. As you pump more water into the chamber, the air within compresses. That generates pressure that is released with the press of the trigger.

The trigger valve simply opens the pressure chamber so you can direct the water being propelled by the compressed air. By attaching a nozzle to the trigger valve you can control the direction of the escaping water.


Once you know the parts, putting them all together is a simple matter. Connect your reservoir to the pressure chamber with a pump-controlled hose. The pump should be made to slide easily to fill the pressure chamber from the reservoir quickly. Connect the pressure chamber to the trigger valve/nozzle. With a few pumps, you compress the air in the chamber, and then you pull on your trigger valve releasing the water and air in a stream. The more pressure you have the stronger the stream.

The materials you use for your water gun can usually be gathered at most home-improvement stores in the plumbing section.