Making a Drum Rim
Steam Bending Wood
Since wood has an inherent rigidity to it, there has to be a technique employed to soften the bond between fibers so it can be bent into a form. By far, the most effective method is steaming, and it is amazing how pliable wood becomes after being in a steam box. Once pliable, the wood is then wrapped around a form to dry, and the two ends are fastened together.
Using a Steamer Box
A steamer box is a long cabinet built out of plywood with a hole cut in the bottom where a kettle and pipe is fitted in place. Another hole is on top of the steamer box, and is used as a release valve for the pressure, and to check temperature with a thermometer if desired. This hole can be plugged with a rag, making sure it isn’t too tight. On the bottom of the chamber at each end, it is a good idea to put a couple of drain holes. Avoid making it airtight and therefore pressurized. An alternate version uses ABS plastic sewer pipe on two saw horses, with the ends sealed with plastic caps and appropriate holes drilled in the tube.
The goal is to plasticize the wood for bending. Wood cells are held together by lignin. The wood fibers need to be loosened from their lignin bonds, which is accomplished with steam. It generally takes one hour per inch of thickness of wood stock.
Choosing Wood to Steam
Moisture level of the wood is important, and ideally it should be around 20-30% moisture content. Wood can not be steam bent that has been kiln dried, nor even air dried below the 10% threshold. Stay away from both exotic woods and softwoods, as they generally don’t steam and bend very well. Best choices for bending are ash, elm, or oak.
Length of the stock will determine diameter of the drum. Remember, it is 2πr to find the circumference or length needed. So if it is a 14” drum, then the equation would be 2 x 3.14 x 7 (7 being the radius of a 14” drum), which is 44 inches for the length of wood needed. For width, keep it between ¼” and ½” with depth being in the 2” to 3” range.
Steaming the Wood
Next step is to either steam it, or alternatively soak it in hot water for a length of time (usually a day). Once flexible, immediately get it into a circular form. Forms can be made from a wide variety of materials such as plywood cut into circles and stacked together, or a section of plastic sewer pipe that matched the intended diameter. Compression is necessary when bending wood, and the more clamps employed the better.
Putting the Drum Hoop Together
One of the best types of joins for drum making is called a scarf joint. Overlap the ends of the drum frame, and saw across on as low of an angle (approx 20 degrees), so each new end is tapered. The two finely tapered ends join together to complete the circle. Glue them together either with strong waterproof glue like Titebond 2, or reinforce them with wood dowels drilled and glued through both pieces to join them together.
Let it all dry and then the drum rim is ready to use.
Check out Hides for Drum and Rattle Making
A good drum starts with a solid rim
|
What do you think about this article?
Latest Articles