I bought my second pan flute yesterday. They are of a cheap, thrifty variety, and will need careful tuning if I'm to play them in accompanying other instruments. So, I have tuned an older pan flute (which I bought in Cozumel years ago) in preparation. While I have no previous experience tuning anything without a peg or bolt of some kind, I think they came out sounding pretty well. Thus, be wary of the instructions which follow--that said, don't be afraid to try this out for yourself.
Tuning Pan Pipes: A Practical Guide
or, failing that: a lesson well learned
Pan pipes are played by blowing into a tube; the tube then vibrates at a certain frequency, producing a lovely tone. Although you can change the pitch of the note by altering your method of blowing (not covered in this guide), the most effective way to change the frequency of the note is to shorten the tube itself. The simplest way to do this is by caking wax on the bottom of the pipes. All the pipes must all be shortened individually. Lengthening the pipe length, while possible, is tedious and thus will never be covered by this guide.
What you'll need:
wax: I used beeswax, which is available in bulk in many arts and crafts stores, usually sorted with candle-making goods. I got a fat brick of it for $8 a few months ago, when I wanted to make a mouthpiece for my didgeridoo, and still had a great deal of it left over.
a vessel in which wax may be heated and melted. preferably glass or metal. You will also need some method of holding it without burning yourself. I used a thick, glass beaker, which didn't heat up enough to burn; however, if you are using a metal pan, make sure that it has a handle or something, so as not to blister yourself. Furthermore, you are going to have to pour liquid rather precisely from this vessel into the individual holes of your pan pipes; thus, it should be capable of pouring into a small hole. A beaker with a beaked edge, or possible a spout, would be ideal.
a tuner: you can tune your pipes by ear, but that is silly. What you will needs is an electric tuner, ideally chromatic, unless you want your pipes to play the same notes as an open guitar. An electric chromatic tuner with several octaves costs around $30 retail at a music supply store.
small pellets: before putting wax in, you can stuff up the bottom of the pipes with small pellets of some sort to roughly tune it up. This is only necessary if you are tuning a pipe up more than two whole steps, as it can conserve wax. I used plastic Airsoft BB's, however, rice or small beads would work just as well. Get creative! Whatever you use, make sure it won't expand or melt or something.
Tuning the pipes
Throw you wax into whatever heated vessel you are using, and melt it down. Don't let the wax come in contact with an open flame, as it is extremely flammable and will do its best to burn down your house/adobe/loft/tipi. Don't let it boil, or else it may spew up into your face, which is a rather unpleasant feeling. Then again, if you are used to frying foods in oils at high temperatures, you may be used to this sensation.
Once the wax has liquefied, whip out your handy-dandy tuner and blow a note from your pipes. Use your rice or BB's or whatever pellets you are using to tune it to about a 3 half-steps below what you would like the final tuning to be. Now, slowly pour wax into the pipe--not that much, mind you, a half teaspoon should be sufficient to start with. Try not to pour it down the side of the pipe, or else it will build up; instead, try to pour it directly into the bottom of the tube. As soon as you can, blow the pipe and see that the tuning is not too high. If it is too high, quickly pour some wax out: you can either pour it into a mug or some other reservoir, into your palm (make sure it isn't too hot!), or back into the boiling vessel. Wherever you pour it, try not to get particles back into the boiling vessel. The reason for this is simple: there are more enjoyable things in life than picking out small bits of rice or plastic from a vat of steaming hot wax. That said, even if you do get some particles in the wax, it probably won't be a problem.
After pouring the wax into your pipe and ensuring the note isn't too sharp, wait ten to twenty seconds for the wax to solify somewhat, then slosh it around to see if there is are loose rice grains or BB pellets or whatever. If there are, and the pipe is less than a half tone from being in tune, you may try to secure it by pouring more wax in. After pouring, always test to make sure that your notes aren't too sharp! Once all of the particles have been secured, you can fine tune it.
So, now you've poured too much wax in, it got hard, and your note is too sharp. You have two options: re-heating the tube, or scraping it out of the bottom. You can re-heat the tube by pouring more wax in, which will in turn re-heat the wax on the bottom, and then quickly pouring the wax out. However, this only works if the wax you are trying to get out has not had sufficient time to solidify. You could heat the pipes via an external source, such as a burner, lighter, or microwave, but you then risk damaging your pipes, and if you opt to use a microwave, you may screw up the tunings on tubes which have already been completed. It may be easier to scrape the wax our with a long, thin blade or a drill bit.
Keep in mind that your tuner readings may vary nonsensically; this is because (as said before) the note produced will also depend on your method of blowing into the pipes. Because of this, it is important to try and keep an even blow when tuning all of the different notes!
Also, the tuning of the pipes may change as much as a half tone after the wax is given time to dry. Be patient, this takes time. Luckily, pan pipes are rather enjoyable to listen to and play, and the honey-like smell of melted bee's wax isn't entirely unwelcome either.
Make sure wax doesn't cake up any of the pipe's rims. The sharp edge on the top of the pipe will help produce tones, if it is caked with soft, delightful wax, it will not sound.
This is all the advice I can provide. If you feel I've missed something or failed to explain any part in sufficient detail, let me know. Good luck tuning your pipes!