The pan flute is an extremely popular instrument in many musical cultures, perhaps most notable for its use in South American music. While pan flutes are traditionally made out of reed cane, it's also possible to make a nice sounding and inexpensive pan flute using PVC pipe and materials easily obtainable at any hardware store.
Measure and cut the 1/2-inch Schedule 40 PVC pipe into pieces of the following lengths, in inches, using the measuring tape and hand saw: 12.75, 11.5, 10.25, 9.5, 8.5, 8, 7, 6.5. Take care to make your cuts as level as possible.
Sand the outside edge of both ends of each piece of cut PVC pipe until they are completely rounded and smooth. Use the 250 grit sand paper. Make sure you don't remove the inner edge of the pipe, which should remain as angular as possible. Sound is created as air is blown over the curved outer edge of the pipe, and then passes across the sharp inner lip -- so it's important for the outer edge to be extremely rounded and the inner edge to be extremely crisp.
Lay out the sanded pieces of pipes along a flat working surface, arranged from longest to shortest. Align the pipes so their top edges are even, and each pipe's sides are touching the sides of the neighboring pipes.
Apply a generous layer of PVC cement between each pipe, gluing the pipes into a long chain. Allow at least an hour for the cement to dry.
Flip the pipes over carefully and apply a second coat of PVC cement to the other side of the pipes. Allow the cement to dry and cure for 24 hours.
Insert a 1/2-inch rubber plug into the bottom end of each pipe. Only insert the plug far enough so it will stay in place.
Turn on your tuner and blow across the lowest pipe. The tuner should register an extremely flat C. As you blow, slowly press the rubber plug farther into the pipe, until the C comes up to pitch, and is in tune. Repeat this process for all of the other pipes, tuning D, E, F, G, A, B and high C.
It's possible to glue the rubber plugs in place once the instrument is tuned. Many musicians, however, choose to leave the rubber plugs free, so they can be re-tuned as necessary.