This garage door does not cover an automobile, rail vehicle or aircraft, but a set of skis. These skis have in common that they are specifically designed for use in deep snow (off-piste). These skis are called freeride and touring skis, which should float on the snow as well as possible and avoid sinking. In order to generate the best possible lift on the snow with the ski, a sandwich wood core that is as light as possible is used in addition to the wide shape.
Just as the first skis were made of wood, a large part of modern ski technology continues to use wood as the core material. Different types of wood can be combined to achieve particular (mechanical) properties. To produce these wooden sandwiches, wooden sticks are arranged and glued together according to their use. Combinations of beech and poplar wood and, in special variants, paulownia wood are used. The beech wood provides the necessary stability and strength under the binding for the screw connection to the ski binding. The poplar wood is very light with a density of less than 0.5 g/cm³ and gives the ski a special flexibility. Compared to the poplar wood, the paulownia wood is quite a bit lighter. Due to the density of less than 0.3 g/cm³, the wood can contribute considerably to reducing the weight. In freeride and touring sports, particular importance is attached to the weight of the wood, as every additional gram is transported up the mountain by the athlete, especially in touring.
By using wood sandwich cores, harder types of wood can be used in areas subject to higher loads, such as in the binding area. In less stressed areas of the ski, weight can be saved by machining the wood with CNC routers; in addition, sandwich technology enables the local insertion of lighter, but therefore softer wood species such as poplar or paulownia. This method ensures that the freeride and touring skis do not become too heavy despite their wide shape and that they do not sink in the snow.