Have you ever wondered how a spiral wooden stair case gets its curvy handrail? Well, the answer wood bending. Wood is a great natural resource that provides earth’s residents with all sorts of its construction needs. When we want to be a little more creative in our building, wood lets us expand our design capability.
The pliable medium of wood lets us twist and contort it into any variety of shapes and sizes. This process isn’t a simple as it sounds as you have to weaken wood’s natural tensile strength before you can manipulate it. Here are a few methods to turn a straight piece of wood into a work of art.
Steam Bending Wood
Steam bending is the most widely used bending method. Before you even begin to steam your wood your clamps must be set into place in the shape you want your wood to be. Taking your steamed wood and instantly placing them into the clamps will ensure your bend as long as the wood itself does not have any slight breaks or impurities to prevent the bend.
Steaming the wood is done by placing the piece to be bent into a steam “box”. The box can be a wooden box or a piece of metal pipe but usually it is a piece of PVC pipe large enough to hold the wood piece. You will need a hot plate and a container to boil the water for the steam.
A hose will then need to be fed from the container into the PVC box for the steam to reach the box. The ends of the PVC should be sealed as not to let all the steam escape but do make a small whole for some steam to be release so pressure will not build up inside the box.
The piece of wood should be steamed for one hour per inch of thickness of the wood. Once the time is up take the wood from the steam box and set it in your mold or clamp base. Remember you are dealing with heated water and to protect your hands.
Once the wood cools it will retain the shape of the mold. Let the wood dry properly before removing from the mold or you will have bend back of the wood and will have to re-steam it.
Wood bending with kerf cuts dates back into ancient history. It is the simplest way to bend a piece of wood. It is accomplished by cutting parallel slots along the opposite end of the wood that you want shown. Each slot is called a kerf.
The kerfs open up areas and allow the bend to come in on itself. This weakens the one side so that it can bent cold. Guitar makers use kerfing as the separate little blocks that allow for the bending are ideal for making the linings.
Soaking is self explanatory. Submerging a piece of wood into water allows the wood fibers to absorb water and expand. This makes the wood piece floppy and able to be bent cold. This method also is less damaging to the wood during the bending than other methods.
Soaking has one drawback. Soaked wood will not hold its shape once bent as heated wood does. Once a piece is soaked and bend it must be form fitted and secured onto a mold. If a soaked piece of wood were to ever be released from this mold it would become straight again.
This process uses smaller strips of wood that are glued together and placed into a molding. Furniture makers use this process more than other wood workers. It is a bit more labor intensive than other forms of wood bending but the finished product is the same.