To go along with the 5 Gal. Diving Helmet intstrucatble I made, I built a pvc pipe pump to supply air to the helmet. All you need to connect the pump and helmet together is a garden hose. You can build the pump to any size you want, but this was all made on a cost of $30-35.

All the parts I bought were from Ace Hardware and lets just say the more complex pvc parts cost more than $2, which was a little alarming for me at first, but I was like "screw it, i'll pay!"

Step 1: Materials and Tools

When I stopped by Ace to get the parts, I recieved a lot of help from one of the workers. The parts that make up the nozzle were a brass Pipe-to-Hose fitting, two outer-threaded connectors, and a part whose name i cannot remember but it was essential to let air be sucked into the chamber and pumped into the helmet. Anyone can refresh my memory about this part.

Tools-
Hacksaw
Drill & Large Drill Bit
Dry Erase Marker
Duck Tape

Step 2: Building the Pressure Chamber

Since i can't remember the names of the parts, you'll have to refer to this picture on where to put stuff together.

Step 3: Assembling the Plunger

For the plunger, I used the thinner pipe and two threaded attachements for the shaft. The plate was made of two cardboard coins and a piece of fleece. I cut holes in the centers on the three circles and insert the threaded plug into all of them. Then I put the plug into the attachment and duck tape the part and pipe together so they would't come apart when I slid the plunger through the cap.

Before I added the handle made of excess PVC and duck tape, I drilled a hole slightly larger than the diameter of the plunger pipe. When it fit well, i put the cap on the way it should be facing and taped on the handle.

Step 4: Seal and Finished!

After I attached the cap to the chamber, I added more tape to various areas to seal it up and contain more pressure. Added some tightening to the nozzle parts, tested out the force of compression and I was finished! So now I am ready to test out my diving helmet!