1. You're going to need a steam box. We made ours. Click here for information on how to build a steam box.
2. Obtain a piece of wood for the bodhran rim. We used a plank about seven feet long, 4-5 inches wide and one-third to one-quarter of an inch thick. Green ash is supposedly the type of wood most commonly used for bodhran rims, but all we could get was kiln-dried oak and it worked fine.
(Note: Look at the end of the plank to see the arc of the grain. The outside of the bodhran rim should be the side that the annular tree rings curve away from. This will help prevent splitting when the wood is bent.)
3. You want to make sure that when you bend the plank into a circle, you'll get a drum rim of the desired diameter. Eighteen inches is the most common diameter that I've seen for bodhrans. So;
Because we'll be using a scarf joint to attach the two ends of the rim, add another six inches. So overall, the plank should be 62 inches long.
4. Taper both ends of the plank so that when the wood is bent into a circle, a scarf joint will be formed. This type of join is strong and fairly inconspicuous. (See Diagram - Scarf Joint.)
5. Use a router to put a groove in the outer side of the plank, about one inch down from where the drum skin will be. Make the groove about 3/4ths of an inch wide and 1/16th of and inch deep. Once the rim is complete, the edges of the skin will be fastened into this groove with tacks.
6. Build a circular wooden form around which the plank will be bent. It should be about 5-6 inches thick and of the same diameter as you wish your drum to be. It should also have some holes cut into it to facilitate the use of clamps. Click here to find out how to build a rim mould.
7. Put the plank in the steam-box and fire up your steam source. Once you're sure that steam is flowing nicely into the steam-box, shut the door tightly. It should get as hot as a sauna in there. Lower the end of the steam-box that has the drainage hole so that excess water can run out. You're now working with scalding water, very hot wood and steam, so wear protective gloves and clothing.
8. Put the plank in the steam box for two hours. Turn it over occasionally to allow both sides to be heated equally. (I've read that wood should be steamed for six hours, but two seems to be enough in this case).
9. Remove the plank from the steam-box, and with a friend, immediately bend it around the mould. You should do this while the wood is still hot. You will probably have to use a good deal of force, especially near the ends. As you bend the wood, a third person can add clamps to hold the plank in shape around the mould. Try to make the two tapered ends of the plank overlap.
10. Leave the plank clamped around the mould to cool and dry over-night.
11. Hard part: The next day, loosen the clamps a little at the place where the two ends of the plank overlap so that they separate a little bit. Put a coating of carpenter's glue or wood epoxy in there and re-tighten the clamps so that the ends meet once again. Wipe away any glue that oozes out between the sandwiched ends.
12. Leave the glue to dry overnight.
13. Once the glue has dried, remove the clamps and take the rim off of the mould. You should now have a rough hoop of wood. Don't worry if it's not a perfect circle. A slightly odd shape shouldn't affect the sound of the drum significantly.
The glue should be sufficient to hold the scarf joint together, but you may want to strengthen the join even further with wooden plugs. I bored a few half-inch holes the into rim where the two ends overlapped and tightly tapped in some wooden pegs coated with glue (half-inch dowels cut to length).
14. You now have the basic bodhran rim, although it might not look very pretty. You still need to cut away, plane and sand down any extra pieces of wood so that the join looks just like its part of the rest of the hoop.
15. At this point, you may want to add a cross-beam to the rim so that you can hold the drum while playing it. To do this, fasten a single 3/4 inch wooden dowel or two perpendicular dowels inside the rim with screws or nails. I've heard that some people use crossed wires instead of dowels, or leave the cross-beam out entirely.
(Note: If you choose to add a wooden cross-beam, then you will also have the opportunity to correct a misshapen rim (i.e. an oval or egg-shaped rim). To do this, submerge the section of the rim which is most misshapen in water overnight (do not submerge the scarf joint if you have used a water soluble glue). The submerged area will become just flexible enough so that it can be temporarily forced into a more correct shape by hand or with clamps. Once the rim is being held in a more circular shape, wedge the cross-beam or cross-beams into place, and release the rim. The cross-beam should hold the rim in the corrected shape. Permanently fasten the cross-beams in place with nails or screws driven through the rim and into the ends of the dowels from the outside.)
16. Briefly steam and then bend another thin and narrow strip of wood (about 1-1/4 inches x 1/8 inch). Add this thin wooden ring to the inside top of the drum with glue and short finishing nails. This will ensure that when you mount the skin, any tacks you nail into the outside of the rim will not poke through. Finally, taper the inside top of the rim to prevent the skin from buzzing when played. (See Diagram - Taper and Inner Ring)
17. Sand and finish the rim however you like (rub in Dutch oil, stain, lacquer or paint it, etc.).
18. The rim is done, but your bodhran is only half complete. You need a skin .