Ski Wax Adhesion vs. Glide Performance: The UHMWPE Dilemma – Part V

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MATERIAL SCIENCE · RESEARCH SERIES

UHMWPE Ski Base Weaknesses

PART V OF V

Fifth issue of the existing UHMWPE ski base types is their very low ability to bind gliding ski waxes and other gliding agents chemically.

How it works?

Chemical bonds between UHMWPE and wax-based gliding agents are very weak, chemical bonds between carbon black as main structural and reinforcement additiv in modern ski base types are extremelly weak. In other words: if applied on a ski base, wax-based gliding agents cannot rely on chemical bonds, they urgently need mechanical retention.

UHMWPE Ski Bases: Limited Wax Absorption and Retention – Part IV

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MATERIAL SCIENCE · RESEARCH SERIES

UHMWPE Ski Base Weaknesses

PART IV OF V

Forth issue of the existing UHMWPE ski base types is their low and uneven capacity to take and hold other substances as gliding ski waxes and agents.

How it works?

Only sintered ski base types have sufficiently long chains to create free space to take wax molecules on the very top surface and inside the bulk material.

Why UHMWPE Ski Base Surfaces Change So Quickly – Carbon Black and Wear – Part III

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MATERIAL SCIENCE · RESEARCH SERIES

UHMWPE Ski Base Weaknesses

PART III OF V

Third issue of existing UHMWPE ski base types are the fast changes of the ski base surface.

How it works?

We know that the main component of UHMWPE ski base types is PE with extremely long linear molecular chains (normaly 7 to 12 mil. g/mol) which is enriched with different additives where the most important is soot or carbon black.

Ski Base Wax Memory: Why UHMWPE May Retain Residual Wax – Part II

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MATERIAL SCIENCE · RESEARCH SERIES

UHMWPE Ski Base Weaknesses

PART II OF V

Second issue of existing UHMWPE ski base types is the ski base memory of gliding waxes.

How it works?

Only sintered ski base types have sufficiently long chains to create free space to take wax molecules on the very top surface and inside the bulk material.

On the very top surface we call the free spaces “flokati carpet” which are fibres or hairs several hundred nanometers long which are covering the entire ski base surface. Between these fibres is enough space for wax molecules get in and get stuck here. Most wax molecules are allocated here.

UHMWPE Ski Base Manufacturing: Cooling, Crystallinity and Material Variability – Part I

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MATERIAL SCIENCE · RESEARCH SERIES

UHMWPE Ski Base Weaknesses

PART I OF V

What Are the Main Weaknesses of Existing UHMWPE Ski Base Types?

A Five-Part Analysis of Material Limitations and Their Impact on Ski Glide

Modern cross-country ski bases are predominantly made from ultra-high-molecular-weight polyethylene (UHMWPE), often modified with carbon black and other additives.

Why Has No-Wax Chemistry Emerged in Ski Glide Preparation?

No-wax chemistry is a clear reaction of the wax industry on the extremely low life time of liquid waxes based on dissolved waxes. 

The life time of waxes applied on the ski base is quite low in general. Due to very weak chemical bonds between waxes and PE, waxes need to rely on mechanical retention inside the ski base. Only waxes which can penetrate the ski base – or better: free cavities in the amorphous regions – can be retained more strongly providing longer life time.

Waxes sticking to the very top surface of the ski base – with no retention inside the ski base – can last for an extremely short time.

Cheap vs. Expensive Liquid Ski Waxes: What Is the Real Difference?

Normally the main difference is the life time / stability / wear resistance… in other words how long the improved gliding properties can last under given snow and weather conditions.

 

Normally the cheaper liquids last on the ski base for a much shorter time and therefore provide a much shorter improvement of gliding features.

 

Why? Most of the cheaper liquid gliders are solutions containing two main components: active ingredients dissolved in a carrier. The carrier is responsible for liquid state of the solution, enables application on the ski base in the liquid form. After application the carrier evaporates more or less fast and leaves only the solid component on the ski base.

Which Ski Base Components Matter Most for Glide Performance?

 

 

Even if specialized magazines and articles mention many different additives and ingredients used in ski bases of competition skis, finally we will find out, if we look in much more detail, that there are only two main components which influence the most important features of each ski base type, especially now after fluor ban.

 

First is the UHMWPE itself which defines the features of the matrix. The matrix itself can get touch in contact with snow surface, that’s the reason why PE is used, because currently there is no other polymer with such a low coefficient of friction and so high hydrophobicity available. With respect to other components the matrix is responsible for the wear resistance and fixation of additives.

 

For wear resistance the most important figure is the length of molecular chains, the higher the length of molecular chains, the better the wear resistance. Reaching the value of 10.000.000 the polymer can be hardly processed.

 

Additive fixation in UHMWPE is problematic. The most additives do not form strong chemical bonds with the base matrix. Additives are bound in the matrix either by very weak chemical bonds or by mechanical retention. Especial close to the surface where the contact snow and ski base surface take place especially the mechanical retention decides.

 

The most important additive used in modern ski base types is soot or carbon black. The importance is given by the amount used in the competition ski base types which reaches up to 20 % of weight fraction in Nordic skis and up to 40 % of weight fraction in Alpine skis and by the way how carbon black is fixed in the PE matrix.

 

Some carbon black is incorporated directly in the PE matrix, but most of carbon black is filling the free space or cavities between the PE corns which are sintered together using heat and pressure. Especially the second type of soot fixation is responsible for high values of E-modulus which decides how ski base changes elastically under load.

 

Wax History in UHMWPE Ski Bases: Does Previous Waxing Matter?

We know that the very surface of the UHMWPE ski base is created by crystalline, amorphous and transition regions. In crystalline regions no wax can penetrate, transition regions are insignificant with respect to the area, the only ski base fractions where wax can penetrate are amorphous regions.

Amorphous regions consist of disordered structure of PE molecular chains with free cavities which size is in the order of tens of nanometres. In these free cavities there is enough space for wax molecules to get in and get stuck after hot wax application.

Technical Snow: How Artificial Snow Differs from Natural Snow?

 Technical snow. We have already touched on this topic several times. We have already mentioned several times that technical or artificial snow, in short, so-called man-made snow, is not actually real snow. Today we will take a closer look at the specifics and unique properties of this human creation.

 

Artificial snow is produced by using a pressure pump to drive a stream of water to a sprayer, where it is broken into small water droplets of approximately 0.1 mm in size. The droplets of the broken water must not be much larger or much smaller than 0.1 mm. Larger droplets risk not freezing sufficiently, while smaller droplets risk evaporating after contact with cold air or being blown away by the wind outside the snow-covered area.

 

How Does Ski Wax Stick to UHMWPE Ski Bases? – Part 3

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SKI BASE MATERIALS · RESEARCH SERIES

How Does Ski Wax Stick to UHMWPE Ski Bases?

PART 3 OF 3

We know that there are main principles how waxes are connected to the ski base. Some waxes penetrate into the inside molecular structure of the ski base which is accessible for waxes only if wax is in the liquid state and ski base is more flexible due to heat. Some waxes stay on the surface and “fill” only surface imperfections and roughness where waxes are partly retained in the “open” surface structure mechanically partly connected with weak chemical bonds.

Attention: surface imperfections and roughness cannot be confused with grinded or imprinted additional structure created by stone-grinding machines or manual structuring equipment. Surface imperfections are related to flat ski base here.

How Does Ski Wax Stick to UHMWPE Ski Bases? – Part 2

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SKI BASE MATERIALS · RESEARCH SERIES

How Does Ski Wax Stick to UHMWPE Ski Bases?

PART 2 OF 3

To understand the way how the additionally applied wax sticks to the ski base, we need to go a bit deeper into the topic…

Here we do not distinguish between chemical bonds and mechanical retention in general as we did in the part I., but we concentrate on the position of the wax in or on the ski base.

If we speak about how wax sticks to sintered UHMWPE ski base types, we need to distinguish between 1. wax penetration into the inside structure in the ski base and 2. wax adhesion to the ski base surface.

Racing Ski Bases: Can Performance Additives Reduce Wax Retention?

The Advantages and Potential Limitations of Racing Ski Base Materials

Racing cross-country skis are normally equipped with high-performance UHMWPE ski bases specifically designed for competitive skiing.

Manufacturers commonly offer several ski base types optimized for different snow conditions, typically cold, wet and universal conditions.

These ski base types differ not only in their surface structure but also in their material composition, including the types and concentrations of additives incorporated into the UHMWPE matrix during manufacturing.

No-Wax Ski Glide Chemistry: How Do Alternative Surface Treatments Work?

Why Look Beyond Conventional Ski Waxes?

Most modern fluorine-free ski glide products, including traditional hot waxes, liquid waxes, powders and speeders, still rely on wax-based formulations.

These products may contain different combinations of paraffins, synthetic waxes and functional additives designed to improve glide performance under specific snow conditions.

However, conventional wax-based treatments face one fundamental limitation:

How effectively can the applied material remain attached to the UHMWPE ski base surface during sliding on snow?

REX NF41 Liquid Ski Wax: Application, Adhesion and Wear Resistance

Why Is REX NF41 So Interesting?

REX NF41 is a fluorine-free liquid ski glide wax designed particularly for demanding snow conditions, including wet, coarse and man-made snow.

According to the manufacturer, NF41 contains an extremely hard UHW (Ultra-Hard Wax) polymer wax blend intended to provide excellent durability even under highly abrasive conditions.

This makes NF41 an interesting product from a material science and ski preparation perspective.