Pressurized Air Water Gun

In this set on instructions i'll show you how to make a cheap and easy to make air-pressured water gun.

This gun should be able to fire a stream of water to a distance of 7-8 meters (at least).

There are versions of this gun using a more "professional" rig, but it's far more complex to assemble.

In addition, these guns use even higher air pressure instead a rigid PVC body, which may explode or launch itself at someone.

This gun should be safer, since if the pressure is too high leaks will probably occur.

Still, this build is based on high air pressure, and may be dangerous.

Use it at your own risk.

The author of these instructions will not be responsible for any damage to person(s) or property.

This water gun was built during the 2014 Geekcon, an Israeli makers hackaton/convention.

2 plastic bottles, preferably with large caps (you'll need the space)

About 6 meters of houseplant water drip tube

Adhesive tape

Spray paint

Car air compressor

Tools:

Hot glue gun

Soldering iron or an electric drill

Box cutter knife

Scissors

You can use either a drill or a soldering iron. The holes should be a little smaller than the diameter of the tubes, so you'll need to use some force to force the tube into the holes.

One tube should connect the two bottles and two more should extend from the bottles outwards, one for each bottle. This means each bottle has 2 holes.

One of the tubes outwards going tubes should extend inside the bottle all the way to the bottom. This bottle will be the water bottle. The other bottle will be the air bottle.

Use the hot glue gun to cement the tubes into the caps. Make sure the tube's diameter is completely encased in hot glue.

Do this for both sides of the cap.

This step is crucial: Bad seal means air/water can escape, and you lose pressure. If needed (if you hear air escaping when you test the complete rig), remove the hardened hot glue with pliers or a cutter and redo the cap.

Add a valve on the tube coming out of the water bottle (the one not connected to the second bottle).

Try find a valve in which the diameter of the in/out ports is as close as possible to the tube's diameter.

If the valve port is a little wider, wrap the end of the tube several times with adhesive tape, thus increasing it's diameter. You should use some force to push the end of the wrapped tube into the valve's port.

Repeat the process with another second of the tube which will be connected to the other port of the valve. The water will come out through there.

You can skip this step if you choose to hold the tube sealed yourself, buy folding it back (180 degrees) and pressing a little until it flattens out at the folding point.

Bonus step: Add another valve on the tube coming out of the air bottle. You can also choose to skip this, but if you also skipped the other value you'll need to hold both end of the rig sealed by yourself.

Connect the tube coming out of the air bottle securely to the air compressor.

1. Fill the water bottle and put it's cap in it's place. Make sure the long tube goes down to the bottom of the bottle)
2. Seal the tube coming out of the water bottle (by using a valve or folding it).
3. "Inflate" the air bottle to 60-80 psi (Exceeding the max pressure will cause leaks. Don't be afraid to experiment. You can always remove the hardened hot glue and re-do it).\
4. Seal the air tube connected to the compressor (by using a valve or folding it) and disconnect from the compressor. (which is a cumbersome device to carry around).
5. Open the valve or release the water tube - and let the water flow!

The compressed air in the air bottle "want to get out", so it pushes the water in the water bottle which is "in it's way". Since it's a strong pressure, the water comes out as a string stream.

You can get nice water stream coming out of the end of the water tube, but what about the bottles? Do they look cool enough to you?

If not, put both bottles in a backpack, with the water tube going over your shoulder, and create a cool rig:

1. Find used (and identical) soft drink bottles. Use a box cutter to cut the bottom of each bottle and push the previous bottle's top to the hole you create.
2. Tighten everything with adhesive tap.
3. Use spray paint to get a mean look.
4. Insert the water tube through the "cannon" just made.

Good luck!