Having made a half-dozen or so bamboo didjes, I decided I would share some of my techniques with the 'net. If you come up with any improvements, please let me know.
Making a bamboo didj couldn't really be much easier. First, select a good piece of bamboo - fairly well-cured (don't pick a piece that seems green - they'll be more prone to cracking) and without any visible cracks. Cut it to your desired length (take a look on the Dreamtime site for information on length vs. pitch - there's a handy chart there), using either a straight-backed hand wood saw (e.g. a mitre saw) or a power table or mitre saw (if you use a power saw, it's a good idea to twist the bamboo as you're cutting it (carefully!). This will help avoid splintering.) If you're hand-cutting, you may wish to score around the outside of the bamboo lightly with the saw first, to help avoid splintering. I've also been told that wrapping a piece of masking tape around the bamboo and cutting through the tape will help prevent the bamboo from splintering.
My personal technique is to cut the mouthpiece end of the didj right through the middle of a node in the bamboo - if done carefully, this gives you a nice wide surface on which to construct a mouthpiece. I usually cut the bell end of the didj right above a node (leaving the inter-node space on the didj, and cutting the node off), which seems to help give an unmuffled sound, since a node right at the end would constrict the passageway somewhat. (See the ASCII art at the end of this message for a "diagram".) This also allows you the flexibility to trim a little off the end for tuning (if desired - I usually leave mine untuned, but I also usually play unaccompanied) without ruining the shape.
At this point (depending on the length of your initial piece of bamboo, you may want to do this first, but it's easiest to do after cutting), you need to clear out the nodes from the bamboo. It is important to not leave any significant pieces of nodes blocking the airway, but the goal is NOT necessarily to have perfectly smooth sides either, as the nodes add a certain quality to the sound. If you knock the nodes out until the passageway is round and fairly clear at each node, that should be pretty good. I use a piece of steel rebar (the kind of steel bar they use for reinforcing concrete - I purchased a five-foot piece at a local hardware store just to do this, for about $1) to knock the nodes out. Depending on the length and inner diameter of your piece of bamboo, you may also be able to use a broomstick.
Once you have your didj cut to size, you may wish to smooth the edges of the cuts - I usually use a pocketknife to round the edges, and a piece of medium-grit or fine-grit sandpaper to smooth it completely. At this point, depending on the piece of bamboo, you may be done - if you have a nice thick node at the mouthpiece end, and the inner diameter is not too large, and you round the edges out nicely, you may not need a beeswax mouthpiece at all.
If you do need a mouthpiece, which is likely, you'll need to acquire some good beeswax. You need the stuff that is a rich gold color (like the background of this section, if your browser supports stylesheets), somewhat soft to the touch, not the hard, translucent-yellow paraffin-like stuff sold for threading needles. Try a candle-making store. I bought a big hunk (a pound?) a couple of years ago for $5, and still haven't run out.
Break off a comfortable-sized piece of beeswax (about the size of a large marble) and roll it in your hands until it is warm and pliable (you may want to use a toaster oven (NOT a microwave!) or flame to help soften it, but I don't), and smear it on the flat edge of the node at the mouthpiece end, then repeat, building up a mouthpiece of your desired shape (tastes differ widely - you're on your own here) a layer at a time. There's also an entire page on making beeswax mouthpieces on Dreamtime.
Here's a diagram:
_____________________________________________________________
/| ___________________ ____________________ _________________
\|/ \/ \/
Mouthpiece end node node Bell end
/|\___________________/\____________________/\_________________
\|_____________________________________________________________
^beeswax mouthpiece
That's pretty much it. I personally love the sound of bamboo didges - it's very resonant, a great ambient meditative sound. I just acquired my first eucalyptus didj, and although it is much more "active" (very agile, easier to play fast rhythms and vocalizations, and MUCH easier to bend the pitch with), I prefer the resonant sound of the bamboo for meditative and trance music.
Earthlove,
-Chris
Free license granted to reproduce this material in any medium, provided credit is attributed and material is not edited without prior written approval.
Last changed July 15, 1997.