In order to understand proper ski or snow board waxing techniques, it is important to understand the composition of the base. High density polyethylene is a widely used polymer, typically referred to as “plastic”. Polyethylene is inert to the majority of chemicals, but also considered to quite soft. Polyethylene does not absorb moisture (hydrophobic) and can be shaped to form structure on the surface of the base, making it perfect for constructing ski and snowboard bases. However, the softness also has a downside. It can scratch, gouge or pick up dirt. Ski shops may repair any damages incurred on a base with P-Tex or a weld, depending on the severity of the defect.
Ski manufacturers create bases with fine polyethylene powder, which is heated and pressed into shape through a process called sintering. A structure of fine grooves is then added to the base in order to channel the water from the tip to tail of the ski or board as it glides over the snow, a concept similar to that of the treads of a car’s tire.
Even though polyethylene is quite inert, it can still oxidize and form a white chalky layer when exposed to ultra-violet light. This oxidation can cause the ski or board base to become brittle and crack. Over-heating the base, such as during the waxing process, can also harm the polyethylene and structure of the base. A crystal structure in the polyethylene is formed during the manufacturing process, and adding too much heat can change this structure and make it amorphous (not crystalline).
Two physical properties of interest when considering the right polyethylene for a ski or snowboard base is the thermal glassy transition temperature (Tg) and the temperature at which the material melts (Tm). Tg is the temperature at which the plastic is in a molten, or rubber-like, state. Polyethylene’s Tg is -125°C. Generally, lower Tg temperatures signify softer plastics. Harder more brittle plastics will correspond with a higher Tg . On the other hand, the melting point of polyethylene (Tm) dependents on the density. High density polyethylene’s melting point ranges from 248°C to 266°C, while low density polyethylene Tm ranges from 221°C to 239°C. These two properties of the polyethylene will determine the flexibility and durability of the plastic.
Knowing the composition and properties of the ski or board’s base helps to understand the importance of waxing. Waxing will prevent the board or ski from oxidizing. The wax will provide a layer of protection on the base that will prevent the UV light from destroying the polyethylene. Wax will also prevent dirt off from coming in direct contact with the base. However, it is critical that wax is applied properly and frequently. If the iron-on technique is used to wax the ski, one should closely monitor the temperature of the iron. Too much heat can damage the base of the ski or board. Although the melting temperature is generally much higher than the iron temperature, applying excessive amounts of heat for long periods of time (i.e. holding the iron in one place on the base) will cause the structure of the base to become amorphous and softer. Therefore, set the iron temperature to the wax’s specific melting point and keep the iron moving constantly when applying the wax to the base.
For those technicians that feel the direct heat from the iron to the ski or board’s base is detrimental to the structure, an alternative technique exists. Once the wax is melted and dripped to the base, a piece of parchment paper (available from the grocery store in the isle near the aluminum foil) can be placed over the base. Then, place the iron on top of the parchment paper and melt the wax further, while spreading the wax across the entirety of the ski or board. When finished ironing in the wax, leave the paper in place until the wax hardens completely. It can then be removed easily, as wax will not stick to parchment paper. In addition to the protection feature of the parchment paper, it also hold in the heat longer and forces the wax to cool at a slower rate. This increases the wax’s penetration into the pores of the base. This is a similar theory to using a “hot box” to keep the wax softer for longer, while it penetrates the pores and cracks in the polyethylene.
Green Ice Ski Wax is available in various grades of waxes to suit the needs of any skier or rider. These waxes apply easily and safely using either iron-on or rub-on techniques with no threat to the health of the athlete.
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