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How to Arch Balsa Wood

Laurel Storm

Balsa wood is the material of choice for the construction of model aircraft, for good reason — it is light and soft, yet very strong. During World War II, balsa wood was even used to produce a full-scale airplane: the de Havilland Mosquito, a fast-moving bomber also known as "the Wooden Wonder."

Balsa wood can easily be shaped into curves and arches, although following some specific practices is necessary to ensure that the wood will arch without splitting or breaking.

  1. Fill a container with a mix of equal parts ammonia and warm water. The container should be large enough for the piece of balsa wood to easily fit in it.

  2. Submerge the balsa wood in the container and leave to soak for at least one hour. The ammonia will break down the balsa wood at a cellular level, making it more flexible.

  3. Place the soaked balsa wood on the template, adjust it to the desired arch and tape it down firmly using the masking tape. Always bend balsa so that the grain runs the length of the piece. This will make the bending easier and the finished piece stronger.

  4. Leave the balsa wood to rest for at least one full day, until completely dry. Depending on weather and temperature, the drying process may take as long as two or three full days.

  5. Remove the dried balsa from the template.

  6. Tip

    Use A-grain balsa wood, especially when working with difficult or complex curves. A-grain is cut on a tangent to the growth rings and as such is the most flexible type of balsa. Anything can be used as a template, even common household objects such as coffee cans. Once the drying process is complete, the wood will spring back a little bit when removed from the template. This is normal.


    Always work in a well-ventilated area when using ammonia.