On most familiar dulcimers, the sides are serpentine—not just for looks, but for strength as well. The curved sides resist pressure in the same way that a curved beaverdam does. Straight-grained wood shaved down to Vie-inch thickness will bend with little trouble. You can easily ripsaw down the edge of 1 ^-inch-thick wood for 3 feet to make this thin stock Take good care as you plane down to the final smoothness and thickness. Any grabbing and tearing of the grain will weaken the wood at that point and cause it to snap or bend unevenly. Using a scraper and constantly checking for thick spots (you can't do much about thin spots) is a safe way to work. Interesting wood, like interesting people, can be challenging to work with.
Successful bending of the sides, then, starts with the right wood carefully brought to an even thinness. Bending against a hot pipe exploits the plastic nature of wood by softening the lignin and cellulose so that they bend easily and take a permanent set when the wood cools. Some workers use more water in this process than others, but the object is not to steam or soak the wood into limpness (although some work that way). Dampen the wood just enough to keep the surface that comes in contact with the hot iron from scorching.
Start bending a curve by heating the opposite (convex) face of the bend. Keep the wood moving over the surface of the pipe. When it gets good and hot, flip it over and, still constantly moving the wood, push down to bend it. You will feel the wood give once it is hot enough. If you bend woo around a hot stovepipe, you will know not to push too hard or you will knock the pipe loose from the woodstove and cause a fire.
Bend the sides until they match the traced paper pattern of the dulcimer you are copying. As you gain experience, you will find places where you want to overbend or underbend to build tension into the instrument, but for now, just try to get it on the line. Hold each curve until it is cool and it will stay put with very little springback.
"The Woodwright's Eclectic Workshop" By Roy Underhill
© 2012 The University of North Carolina Press