A bending iron is a device which is used to bend the wood used to make the sides of musical instruments. Woodworkers can also utilize bending irons when they are making cabinetry and other woodworking projects with curved and bent features. These devices are available through woodworking suppliers and companies which carry equipment for luthiers. Some woodworkers also make their own so that they can control the characteristics of the bending iron.
Hot pipe bending, as it is known, is a traditional way to bend wood for musical instruments. With this technique, the craftsperson takes a sheet of side wood which has been soaked, and shapes it over the hot bending iron. The bending iron consists of a simple pipe or block which can be round or teardrop shaped, allowing the craftsperson to carefully shape the wood in a series of curves which match the back and front of the instrument.
Another technique involves the use of a heated mat and a form, with the soaked wood being heated by the mat and clamped over the form. This technique works similar to the bending iron, using heat to bend the wood and help it set into a desired form. However, it requires much more room and setup, as the craftsperson needs to make a perfect form for the wood, and have space to set up the form and clamps to bend the wood.
Some bending irons come with variable heat settings. This can be used to adjust the heat to match with the type of wood being used, as some woods require more heat for bending that others. The heating element can be electric or gas, with some bending irons consisting simply of a metal pipe heated by a torch. In all case, the metal is chosen because it conducts heat evenly and well, and it will not rapidly cool when the wet wood is pressed against it.
It is important to be aware of the heat when using a wood bending iron. Contact with the iron can be very painful. People usually wear gloves, and they may use metal sleeves with small handles on either end to cover the outside of the wood. Heat will be conducted to the metal, ensuring that the wood is exposed to even heat from both sides so that it will bend without cracking or being otherwise compromised. Many bending irons come with these metal sheets and may include practice wood for people to use while they get used to the operation of the iron.