What are the main weaknesses of waxes? Part no. II – wax softness

Waxes are normally soft, much softer than the material of the ski base. Even if ski wax manufacturers try to mix hard waxes for abrasive and aggressive snow conditions, waxes are normally softer than the ski base itself.

 

If softer waxes are mixed with the ski base material in the top surface of the ski base creating the mixture called gliding surface, the result is always softer surface of the ski base or softening of the ski base surface by adding the wax.

 

The hardest waxes offered currently on the ski wax market like Toko X-Cold Powder / Blue X-Cold, Holmenkol Ultra Base Cold, Swix CHX4 / HSX4 / PS4 (cold powder blue/green series), Maplus Race Base Cold – reach the hardness 40 to 50 shore D which is still below the hardness of the ski base which is normally 65 shore D.

 

If we consider that the wax absorbing capacity in cavities inside molecular structure of a ski base is ca. 5 to 30 % of the thin top layer of the ski base, we can say that on the surface amounting to max. 255 cm2 and min. 38 cm2 of the total 765 cm2 the hardness is reduced by ca. 23 to 38 per cent.

 

If we consider that especially the hardness is the most important factor influencing the gliding qualities or friction especially in cold, hard and abrasive snow conditions, then it could mean that wax application under these conditions is contra-effective.

 

Fortunately for ski wax manufacturers, the question is not as straightforward as it might seem at first glance. It is true that the application of soft waxes reduces the entire hardness at least in the extent where wax molecules are accommodated inside the ski base material. On the other side ski base is protected and intermolecular bonds between ski base surface and snow surface can be blocked thanks to wax application.

 

We need to apply waxes also under cold, hard and abrasive snow conditions to protect the ski base and block intermolecular bonds. At the same time wax application will always decrease the ski base hardness. Especially the hardness is the most important factor influencing the gliding in cold and hard snow conditions.

WHY FRESH POWDER SNOW DOES NOT GLIDE AT ALL?

 Why skiing on fresh powder snow is so challenging?

Fresh powder snow or freshly fallen snow at temperatures below zero and low relative air humidity is extremely challenging for gliding and low friction coeficients.

Why?

Powder snow is crystalline, in other words: individual snow flakes keep their original sharp shape. If they brake during slope or track preparation by pisten bully new sharp edges, tips and forms arise. 

Powder snow contains a high share of air resulting in surface changes of the snow if skis are gliding over it. Such surface changes lead to brittle deformations of crystalls again.

Result:

Sharp, hard, brittle snow crystalls which brake and do not connect to snow pack. The surface of the snow is extremely fragmented - similar to a stone field resulting in few and very small contact points between snow and ski base surface.

Few and very small contact points between snow and ski base surface lead to high pressure in the contact spots. Small contact points, high pressure, sharp / hard and brittle crystalls create a combination responsible for very high friction between snow and ski base surface.

The lower the temperature, the higher the hardness of snow crystalls. At a certain point (for normal ski base types = HDPE at ca. -10 degrees C, for competition ski base types = UHMWPE at ca. - 15 degrees C) the hardness of sharp crystalls exceeds the hardness of the ski base resulting in ski base plowing effect.

Under such conditions you will not want to ski...

Conclusions:

If fresh powder snow is fallen deep below zero, stay at home instead of skiing! If you need to ski in fresh powder snow on a slope, protect your ski base with a hard and hot applied wax coating. If you are a nordic skier, protect your ski base and try to improve the gliding properties the best possible way otherwise your trip can turn in a nightmare - apply hard protecting wax hot with a hot powder coating and liquid speeder!