Paulownia Wood Puzzle

The wood of Paulownia is as valuable timber for the manufacturing of furniture, musical instruments, in boat and aircraft construction and many other areas where an aesthetic and light wood is in demand. Due to the stability in accordance to its low weight, paulownia wood is considered as the "aluminum" among the wood species.

Appearance
Paulownia forms a light wood, with a delicate honey-yellow to light gray color. Its surface is characterized by a silky shine. The characteristic grain of the wood is particularly eye catching due to its broad annual growth rings.

Flash point
The flash point of paulownia wood is with 420 ° C about half time higher than that of ordinary forest woods (270 ° C). For the energy use as firewood such a high flashpoint plays only a minor role, but it makes the wood interesting for applications, where increased fire protection is required.

Weight
With an average weight of only 310 kg per cubic meter Paulownia forms one of the lightest woods in the world. In comparison, our native oak lies at about 580 kg per cubic meter and even our currently as lightweight known spruce gets still at 470 kg. In spite of this low density Paulownia offers a high stability, the wood is preferably used in areas in which priority is given to weight reduction. These include the shipbuilding, aircrafts and construction of mobile homes and caravans.

Surface
Due to its low density, the wood has a relatively soft surface. This can indeed be crafted very well, but also makes it prone to scratches and little damages. To gain the suitability for everyday use, such as a sufficiently hard surface, a finishing step and additional treatment is necessary.

Drying
Depending on how the wood is to be processed, it can be dried both on the fresh air and in drying chambers to quickly reduce the residual moisture content to about 10-12%. Another feature of paulownia wood is in its small degree of remoisturization. Once Paulownia is dried, it hardly takes up water again. In contrast to other types of woods, Paulownia is therefore an extremely dimensionally stable timber. The typical "working processes" of the wood - known as swelling and shrinking - remain absent from here. In addition to the good sound properties of Paulownia this is one of the aspects decisive for the use of wood for various musical instruments.

1. Density
Bulk density at 12% humidity 270 Kg / m3. Very light wood.

2. Dimensional Stability
-4.12 % volumetric contraction . Small shrinkage.
-0.14 % volumetric contraction coefficient . Little nervous wood.
According to the UNE 56540: 1978 standard, the classification of volumetric contraction and the coefficient of volumetric contraction is as follows:

Hygroscopicity of 0.0027 Kg / m3. Weak .

According to the UNE 56540: 1978 standard, the hygroscopicity classification for wood at 12% humidity is as follows:

Paulownia wood has been used in Japan for centuries primarily as a furniture wood. Wooden chests of drawers called Tansu are made from this wood and nearly every Japanese home has a Tansu of solid Paulownia, or sliced Paulownia veneer glued on a Lauan plywood. Other uses of the wood include musical instruments called Koto, wooden clogs called Geta, ornamental carvings, wooden bowls and spoons, bas relief panels, and large and small gift boxes. While the Japanese do not consider this tree "Holy", the wood is held in reverence by those who work with the tree, possibly due to the ability of the tree to regenerate from its own root. This, coupled with its resistance to rot and its freedom from checking and cracking, may account for this reverence.