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.

SKIGO CM26: Does the Recommended Wax Layering Make Technical Sense?

Introduction

SKIGO CM26 is a fluorine-free racing glide treatment developed for exceptionally warm and wet snow conditions.

The manufacturer recommends it for temperatures between +3°C and +15°C, particularly when the snow contains substantial amounts of liquid water.

Under these conditions, glide performance is influenced by several interconnected processes, including water-film formation, capillary effects, friction, contamination and the interaction between the ski base structure and wet snow.

CM26 is an interesting product, but its recommended preparation procedure raises several technical questions.

In particular, why should a treatment designed for very wet snow be applied over multiple layers of conventional ski wax?

And what are the actual functions of these underlying layers?

1. Graphite Wax as the First Layer

Some published preparation instructions recommend beginning with a graphite-based or other hard base wax, followed by scraping and brushing.

A possible explanation is that this initial layer provides a stable foundation for subsequent glide treatments.

However, the physical mechanisms behind such a foundation deserve closer examination.

Graphite and carbon black are different carbon-based additives, and their effects should not be treated as identical.

Graphite has a layered crystalline structure and can exhibit solid-lubricating properties under suitable conditions.

Carbon black consists of fine carbon particles or aggregates. Depending on its concentration and distribution, it may influence mechanical, electrical, thermal and other material properties.

Nevertheless, the presence of either additive does not automatically demonstrate improved glide performance under warm and wet snow conditions.

The critical question is whether a graphite-containing wax provides measurable benefits once it has been covered by additional wax layers and a final racing treatment.

If the graphite wax is scraped and thoroughly brushed, only a limited and non-uniform quantity of material may remain on or within the ski base surface.

It is therefore reasonable to question whether this residual material creates a meaningful separation or stabilizing layer.

A true barrier effect would require evidence that the remaining material substantially changes the interaction between the substrate and the subsequent wax layers.

Without such evidence, the proposed stabilization mechanism remains a hypothesis rather than an established explanation.

2. Yellow Hydrocarbon Wax as the Second Layer

The next recommended step in some published procedures is the application of a yellow hydrocarbon wax suitable for warm conditions.

The detailed instructions currently available recommend scraping and brushing this layer before applying CM26.

This distinction is important.

If the yellow wax were left as a relatively thick, unbrushed deposit, it could fill or partly obstruct the stone-ground structure.

A thick underlying wax layer could also influence the distribution and mechanical behavior of the subsequently applied CM26 treatment.

However, scraping and brushing significantly change the situation.

They remove much of the excess wax, expose more of the original surface geometry and reduce the amount of material available for direct mixing with the following treatment.

Even after thorough finishing, some wax may remain in surface irregularities and structure valleys.

The final surface is therefore not necessarily pure UHMWPE, but neither should it be assumed to consist of a thick continuous paraffin layer.

The central question is whether the yellow hydrocarbon wax improves the adhesion, distribution or durability of CM26 compared with direct application to a properly prepared ski base.

This could be investigated experimentally by preparing identical ski bases with and without the intermediate yellow wax layer.

3. Does Layering Improve or Reduce Surface Performance?

Applying several wax layers does not necessarily result in several clearly separated functional films.

During hot application, compatible components can melt, redistribute and potentially mix.

The extent of this interaction depends on the chemical formulations, temperatures, deposited quantities and application procedures.

It is therefore difficult to assume that each wax layer continues to perform a completely independent function.

On the other hand, it would also be premature to conclude that layering inevitably dilutes the final racing treatment or reduces its performance.

A properly prepared underlying wax may influence wetting, spreading, adhesion or the mechanical behavior of the final deposit.

These effects must be evaluated rather than assumed.

An important experimental comparison would involve:

• CM26 applied directly to a clean, prepared UHMWPE ski base

• CM26 applied over a scraped and brushed graphite base wax

• CM26 applied over a scraped and brushed yellow hydrocarbon wax

• CM26 applied over both recommended underlying wax layers

The resulting glide performance, surface characteristics and durability could then be compared under identical snow conditions.

Such testing would help distinguish between genuine functional benefits and preparation steps retained primarily through established waxing practice.

4. Water Repellency and Wet Snow

Under warm conditions, liquid water plays an increasingly important role in the ski base–snow interface.

However, the relationship between free water content in snow and the thickness of the water film beneath a sliding ski is not straightforward.

Water distribution depends on snow morphology, contact pressure, speed, temperature, surface roughness and drainage through the snow structure.

A greater quantity of free water may increase the risk of capillary-related resistance, particularly when water bridges develop between contacting surfaces.

But more water does not always imply a uniformly thicker lubricating film.

The surface chemistry and structure of the ski base may influence water distribution, drainage and the formation or disruption of these liquid bridges.

For this reason, a racing treatment intended for wet snow should not be judged solely by its static water contact angle.

Its behavior under dynamic sliding conditions is considerably more complex.

5. Dirt Repellency

Wet spring snow frequently contains dirt, organic particles and other contaminants.

These substances can accumulate on the ski base surface and alter glide performance.

The ability of a racing treatment to resist contamination is therefore potentially important.

However, water repellency and dirt repellency are not identical properties.

A hydrophobic surface does not necessarily resist adhesion of every type of contaminant.

Similarly, the chemical composition and mechanical characteristics of a wax treatment can affect the accumulation and removal of dirt.

The performance of CM26 in contaminated wet snow would therefore be worth examining separately from its performance on clean wet snow.

Testing should distinguish between water-related friction mechanisms, contamination effects and abrasive wear.

6. The Importance of Brushing and Surface Structure

The manufacturer's application instructions involve rubbing a thin layer of CM26 onto the prepared surface, heating it with a waxing iron, allowing a short cooling period, scraping and finishing with brushes.

The specified finishing sequence is horsehair, wire and nylon.

This procedure raises an additional question about the relationship between the deposited racing treatment and the underlying ski base structure.

Brushing removes excess material and can help reopen the functional structure pattern.

However, the amount and distribution of material remaining after finishing depend on the geometry of the surface, the properties of the applied treatment and the brushing process.

Some material may remain within structure valleys while exposed peaks are subjected to more intensive mechanical action.

Consequently, the final functional surface may be substantially different from the surface immediately after ironing.

This matters particularly on wet snow, where structure geometry and liquid-water management are closely interconnected.

The important question is not simply how much CM26 remains on the ski base.

It is where the remaining material is located and how it affects the actual contact between the ski base and snow.

Conclusion

SKIGO CM26 provides an interesting example of a modern fluorine-free racing treatment designed for very warm and wet conditions.

The recommended multilayer preparation approach raises legitimate technical questions about the functions of graphite wax, yellow hydrocarbon wax and the final racing treatment.

However, these questions should be considered carefully.

There is insufficient evidence to conclude that graphite wax necessarily creates an effective separation layer.

Likewise, it cannot be assumed that intermediate hydrocarbon wax layers inevitably reduce the performance of CM26.

The effects depend on the actual formulations, preparation procedures and final surface characteristics.

From a technical perspective, the most interesting question is:

Does the recommended multilayer preparation procedure provide measurable glide advantages compared with applying CM26 directly to a properly prepared UHMWPE ski base?

That question deserves controlled testing under representative warm and wet snow conditions.

Only such testing can establish whether the additional preparation steps offer meaningful functional benefits.

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SKIING WITH A SMILE · FOUR-PART SERIES

The Secret of a Reliable Kick

PART 4 OF 4

The Secret of a Reliable Kick – Part 4: Choosing the Right Kick Wax

In the previous three parts, we discussed ski stiffness and geometry, ski base properties and the correct kick zone.

Now we finally arrive at the topic most recreational skiers consider responsible for absolutely everything.

Kick wax.

When the skis do not grip, it is the wax.

When they do not glide, it is the wax.

When snow starts sticking to the skis, it is definitely the wax.

And when your skiing partner becomes unpleasant, the wax is probably responsible for that as well.

Unfortunately, selecting the correct kick wax is not always easy.

And even the best kick wax cannot correct every mistake we have made before opening the first little tin.

Why ISANTIN Requires Different Ski Base Structures

The structure we manufacture is not necessarily the structure that touches the snow

Ski base structures are normally created by stone grinding or manual structuring tools. However, the geometry of the freshly manufactured structure is not necessarily identical to the geometry of the final sliding surface.

Why?

Because the ski base is normally subjected to several additional preparation steps before it comes into contact with snow.

In conventional ski preparation, these steps include cleaning, hot waxing, scraping and brushing. Each of these operations can influence the final surface geometry, particularly at the microscopic level.

This distinction becomes especially interesting when we compare conventional ski waxes with alternative surface treatments such as ISANTIN.

What happens to ski base structures during hot waxing?

The conventional hot-waxing procedure normally consists of several steps:

1. Wax application: Molten or solid wax is applied to the cleaned ski base surface.

2. Ironing: The wax is heated and distributed across the surface. Depending on the material, temperature and application conditions, some wax may also be retained within microscopic surface irregularities.

3. Cooling: The ski base is allowed to cool, typically for approximately 20 minutes, before removing excess wax.

4. Scraping: Excess wax is removed from the flat areas of the ski base using a sharp plastic scraper. Special scrapers may also be used to clean larger drainage grooves.

5. Brushing: Remaining wax is removed from the surface structure using suitable brushes, often equipped with fine bronze or steel bristles.

The last two operations are particularly important for understanding how the original structure may be modified.

Can brushes completely remove wax from structure grooves?

Consider a relatively fine stone-ground structure with grooves approximately 0.5 mm wide and 0.05 mm deep.

A typical fine bronze or steel brush may have bristles approximately 0.1 mm in diameter and 25 mm in length, arranged in bundles.

Although individual bristles are considerably thinner than the groove width, this does not automatically mean that they can reach every part of the groove and remove all retained wax.

Bristle flexibility, bundle geometry, brushing pressure, groove shape and the mechanical properties of the wax all influence the cleaning process.

Consequently, some wax may remain inside the grooves, particularly in their deeper regions or near the transitions between groove walls and bottoms.

Wax remaining in these locations can change the effective geometry of the structure.

The grooves may become shallower, while sharp transitions and edges may become more rounded.

The magnitude of these changes depends on the particular structure, wax and preparation procedure. It cannot be determined reliably from bristle diameter alone.

Nevertheless, the underlying principle is important:

The structure produced by the grinding stone and the structure eventually interacting with snow may be geometrically different.

What makes ISANTIN different?

Unlike conventional hot waxes, ISANTIN is designed to create an extremely thin surface coating rather than a comparatively thick layer of wax that must subsequently be scraped and brushed away.

The reported thickness of the ISANTIN coating is approximately 1–2 micrometres.

If such a thin coating is applied uniformly, it can follow the original structure relief closely without substantially filling the grooves.

This means that the geometry produced during stone grinding may be preserved much more faithfully after the final surface preparation.

In contrast, conventional waxing may modify the original groove geometry through wax retention, incomplete removal and smoothing of microscopic surface features.

The difference is particularly relevant for very fine structures, where even small changes in groove depth, edge shape or local surface curvature may influence the contact between ski and snow.

Why are conventional structures not necessarily optimal for ISANTIN?

Most conventional ski base structures have been developed, tested and refined using waxed skis.

Their successful performance therefore reflects not only the geometry produced by stone grinding but also the subsequent preparation of the sliding surface.

In other words, the effective structure may be the result of two processes:

Stone grinding + surface preparation = final functional structure.

When we replace conventional wax treatment with ISANTIN, the second part of this process changes.

A structure that performs very well after conventional waxing may behave differently when its original geometric features remain largely unchanged.

For example, grooves that become slightly shallower and more rounded after waxing may remain deeper or retain sharper transitions when treated with ISANTIN.

Such differences can influence the distribution of microscopic contact points, local contact pressures, water transport and frictional behaviour.

However, it does not automatically follow that shallower or more rounded structures will always perform better. The optimal geometry depends on snow conditions, ski loading, sliding speed and the properties of the final surface.

Developing structures specifically for ISANTIN

If conventional waxing modifies the original structure while ISANTIN largely preserves it, simply transferring existing stone-grinding patterns from waxed skis to ISANTIN-treated skis may not produce the same functional surface.

One possible approach is therefore to develop stone-ground structures with shallower grooves, smoother transitions or more rounded peaks from the beginning.

The objective would not be to reproduce the original manufacturing parameters used for conventional waxed skis.

Instead, it would be to reproduce — or improve upon — the functional geometry of the final sliding surface.

This requires testing different structure geometries under comparable snow conditions, with particular attention to how they behave after the respective surface treatments.

Conclusion

The development of ski base structures should not be separated from the way the sliding surface is prepared.

Conventional waxes and ISANTIN may produce substantially different final surface geometries, even when applied to identical stone-ground structures.

If ISANTIN preserves the original structure more faithfully than conventional waxing, existing structure patterns may need to be reconsidered and potentially redesigned.

The objective is not to manufacture an identical structure. The objective is to achieve the optimal functional surface at the moment the ski interacts with snow.

What Is the Main Difference Between Cold and Wet Ski Bases?

Not all UHMWPE ski bases are the same

Modern cross-country racing skis are generally equipped with sintered ultra-high-molecular-weight polyethylene (UHMWPE) bases.

Although these materials may look almost identical, their composition and physical properties can differ significantly.

Ski base manufacturers can modify the basic UHMWPE material by adjusting its molecular characteristics, manufacturing conditions and the type and concentration of added particles.

These modifications may influence hardness, elasticity, thermal conductivity, electrical conductivity, wear resistance and surface characteristics.

Consequently, some ski base materials are better suited to cold and dry snow conditions, while others are designed for warmer and wetter snow.

But what is the fundamental difference between these two applications?

Cold snow: predominantly solid-to-solid contact

Under very cold and dry conditions, the amount of liquid water available at the ski–snow interface is generally limited.

The frictional interaction is therefore strongly influenced by direct contact between the ski base surface and individual snow or ice grains.

The mechanical properties of these grains, their shape, size and hardness affect the resulting friction.

At the microscopic level, only a fraction of the apparent ski base area actually interacts with the snow.

The local contact pressures may be relatively high, and deformation, ploughing and abrasion can contribute to the overall friction.

A ski base designed for cold conditions must therefore provide a suitable combination of surface hardness, mechanical stability and low friction against snow crystals.

However, hardness alone does not determine glide performance.

The surface chemistry, microscopic roughness, thermal properties and resulting contact geometry also play important roles.

Wet snow: water becomes a major part of the interaction

As snow temperature approaches its melting point, liquid water becomes increasingly important.

In wet snow, the interface between the ski base and snow is no longer governed primarily by direct solid-to-solid contact.

Liquid water can occupy parts of the microscopic gaps between the two surfaces and form capillary bridges.

These bridges may generate additional resistance to sliding, commonly described as suction or capillary drag.

At the same time, a sufficiently thin water film can provide lubrication and reduce direct contact between the ski base and snow grains.

The challenge is therefore not simply to eliminate water.

The objective is to achieve a favourable balance between solid contact, water-film lubrication and capillary resistance.

This balance changes with snow grain size, liquid water content, sliding speed, applied load and the geometry of the ski base surface.

How can ski base material composition influence glide?

UHMWPE is not a single material with one fixed set of properties.

Different grades may exhibit different mechanical and thermal behaviour.

Additionally, ski base manufacturers can incorporate additives such as carbon black, graphite or other functional particles.

Depending on their nature, concentration and distribution, these additives may affect several properties:

• Thermal conductivity and the local temperature distribution at the ski–snow interface.

• Electrical conductivity and the accumulation or dissipation of electrostatic charge.

• Mechanical stiffness, hardness and resistance to abrasion.

• Surface characteristics and interactions with water.

Nevertheless, the addition of graphite or another functional particle does not automatically make a ski base suitable for either cold or wet conditions.

The final performance depends on the complete material formulation and its interaction with the actual snow conditions.

It is therefore misleading to classify ski bases solely according to their colour or graphite content.

Is hardness the main difference?

One common explanation is that cold ski bases are harder while wet ski bases are softer.

Although differences in hardness may be part of a particular manufacturer's material design, this simplified distinction is not universally valid.

The optimal material must respond to several competing requirements.

Under cold conditions, resistance to mechanical interaction with relatively hard snow grains may be particularly important.

Under wet conditions, the interaction between the surface and liquid water becomes more significant.

However, neither condition can be described by a single material property.

Two UHMWPE materials with similar hardness may exhibit different glide performance because of differences in composition, surface energy, thermal behaviour or their response to mechanical structuring.

Similarly, a material that performs well in wet snow does not necessarily need to be softer than one designed for cold snow.

Why does surface structure remain important?

Even when the base material is carefully selected, its performance strongly depends on the geometry of the final sliding surface.

Fine structures are commonly used for cold, dry snow, while more open and pronounced structures are generally preferred in warm, wet conditions.

But this is not simply a question of groove depth.

The structure determines the distribution and geometry of microscopic contact points and influences how liquid water moves through the interface.

Furthermore, different UHMWPE materials may respond differently to identical stone-grinding parameters.

The same grinding stone and machine settings do not necessarily produce identical surface structures on different base materials.

Differences in cutting behaviour, plastic deformation and the stability of microscopic surface features can influence the final result.

This means that ski base material and structure should not be considered independently.

A successful ski base is a combination of material properties, surface geometry and final surface preparation.

What happens in the real contact area?

At the macroscopic level, the ski load is distributed primarily through the front and rear contact zones.

Within these zones, the microscopic contact pattern is determined by the interaction between snow grains and the textured ski base.

On cold snow, the mechanics of individual solid contacts become especially important.

On wet snow, these contacts coexist with liquid-water regions and capillary interactions.

The relative importance of these processes changes continuously as the snow temperature, water content, grain morphology and sliding conditions change.

Consequently, it is not sufficient to evaluate a ski base material only by measuring its hardness or water contact angle.

Its actual performance must be assessed as part of the complete ski–snow tribological system.

Conclusion: different snow conditions require different surface behaviour

The fundamental difference between cold and wet skiing conditions is not simply temperature.

It is the changing balance between direct solid contact, interfacial water and the mechanisms responsible for friction.

Cold and wet ski bases may therefore benefit from different combinations of mechanical, thermal and surface properties.

However, there is no single material parameter that universally separates a good cold ski base from a good wet ski base.

The best ski base material is not necessarily the hardest, the softest or the most hydrophobic. It is the material whose properties, combined with an appropriate structure and surface preparation, produce the lowest friction under the intended snow conditions.

How Does Ski Wax Stick to UHMWPE Ski Bases? – Part 1

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SKI BASE MATERIALS · RESEARCH SERIES

How Does Ski Wax Stick to UHMWPE Ski Bases?

PART 1 OF 3

It is common knowledge that ski bases are waxed. Many wax manufacturers offer liquid waxes where the wax is dissolved in a rapidly evaporating agent. With a sponge you just apply liquid solution of wax and solvent on the ski base and after the solvent evaporation your ski is ready to be used with improved gliding features!

Waxes penetrate into the ski-base, however, the penetr

How Deep Can Ski Wax Penetrate into the Ski Base?

Does ski wax really penetrate deep into polyethylene?

One of the traditional explanations for hot waxing is that molten wax penetrates deeply into the ski base, filling microscopic pores and becoming stored inside the material.

According to this explanation, heating opens the pores of polyethylene, allowing wax molecules to enter the ski base. After cooling, the pores supposedly close and retain the wax.

But does UHMWPE really behave this way?

Modern scientific investigations suggest a considerably different picture.

Wax penetration into UHMWPE is extremely limited and generally occurs within a very shallow near-surface region.

To understand why, we need to examine the structure of the polymer itself.

UHMWPE is a semicrystalline polymer

Modern cross-country racing ski bases are commonly manufactured from ultra-high-molecular-weight polyethylene (UHMWPE).

UHMWPE is a semicrystalline polymer consisting of two principal morphological regions:

• Crystalline regions, where polyethylene molecular chains are arranged in relatively ordered structures.

• Amorphous regions, where the molecular chains are less ordered and possess greater local mobility.

Between these regions, transitional or interphase regions may also be present.

The relative proportions and spatial distribution of these regions influence the mechanical and thermal properties of the material.

They also affect the potential mobility of smaller molecules within the polymer.

The densely packed crystalline regions generally provide much less opportunity for molecular diffusion than the amorphous regions.

However, the existence of amorphous regions does not mean that UHMWPE contains an interconnected network of open pores capable of absorbing large quantities of wax.

What happens when hot wax is applied?

During conventional hot waxing, the ski base is heated and molten wax is distributed across its surface.

Heating increases molecular mobility and can facilitate certain interactions between wax molecules and the near-surface polymer.

However, the polyethylene does not simply open and close pores like a sponge.

The degree of possible molecular penetration depends on several factors:

• Wax molecular size and chemical composition.

• Polymer morphology and crystallinity.

• Temperature and heating duration.

• Surface condition and previous preparation.

• Diffusion kinetics and compatibility between wax and polyethylene.

For a given material system, diffusion depth generally increases with the square root of time rather than linearly with heating duration.

Consequently, doubling the heating time does not necessarily double the penetration depth.

More importantly, prolonged heating cannot automatically be assumed to improve the functional sliding surface.

Excessive heating may introduce unnecessary thermal stress or damage.

How deep can wax actually penetrate?

Research using physical and chemical surface-analysis techniques has reported extremely shallow wax-affected regions.

Work discussed by Matthias Scherge and colleagues indicates characteristic depths of approximately:

Wax application	Reported depth scale
Block or powder wax	A few hundred nanometres
Spray-applied products	A few tens of nanometres

These results provide a useful indication of the scale involved.

However, the reported values should not be interpreted as universal penetration depths for all waxes, ski base materials and application procedures.

Furthermore, analytical detection of wax near the surface does not necessarily prove that all detected wax has molecularly diffused into the bulk UHMWPE.

Some material may remain on the surface or be retained within its microscopic topography.

The distinction is essential.

Wax present close to the ski base surface is not necessarily wax that has penetrated into the polymer itself.

Molecular diffusion versus mechanical retention

When discussing wax penetration, we should distinguish three mechanisms.

1. Molecular diffusion into the polymer

Small wax molecules may have some capacity to enter accessible amorphous regions of polyethylene under suitable conditions.

The extent of this process depends on the molecular characteristics of both materials and the temperature-time history.

This is genuine molecular penetration.

2. Retention within surface irregularities

Stone grinding, scraping, brushing and wear create a complex surface containing grooves, scratches, ridges and microscopic irregularities.

Molten wax can enter these surface features and remain there after cooling.

This is primarily geometric or mechanical retention.

It should not be confused with molecular diffusion into the polymer.

3. Formation of a surface film

After scraping and brushing, some wax may remain as a thin layer or as discontinuous patches on the exposed ski base surface.

This material contributes to the final sliding interface even if it has not penetrated into UHMWPE.

In practice, all three mechanisms may contribute to the condition of a prepared ski base, although their relative importance depends on the particular treatment.

What about the nanofibrillar surface?

A mechanically processed UHMWPE ski base is not necessarily smooth at the nanometre scale.

Depending on the grinding, scraping and brushing process, its surface may contain plastically deformed regions, oriented polymer features or fibrillated material.

Such features can create local spaces where wax may be retained.

However, we should be careful with the assumption that every ski base possesses a uniform nanofibre layer of approximately 250 nanometres in depth.

The actual surface morphology depends on the material, manufacturing history and mechanical preparation.

It cannot be represented by one universal nanofibre length or cavity size.

A locally fibrillated surface and an amorphous region inside the polymer are also not the same thing.

One describes surface topography; the other describes molecular organization.

This difference becomes particularly important when interpreting measurements of wax distribution.

Is a deeper wax penetration necessarily better?

Not necessarily.

The function of ski wax is to modify the interaction between the ski base and snow.

That interaction occurs at the exposed sliding surface, not deep inside the polyethylene.

A wax molecule located several micrometres below the surface cannot directly interact with snow unless subsequent wear or another process exposes it.

Deeper penetration might influence the availability or retention of wax near the surface, but it does not automatically guarantee lower friction or greater durability.

For glide performance, the most important questions concern the material actually present in the microscopic contact regions:

• What is the composition of the exposed sliding surface?

• How is wax distributed across peaks, grooves and other surface features?

• How strongly is the remaining material retained?

• How rapidly does the functional surface change during skiing?

These questions are more directly connected to glide performance than the maximum possible penetration depth alone.

Why is this important for ski preparation?

The traditional objective of repeated hot waxing is often described as saturating the ski base with wax.

But if genuine molecular penetration is limited to a very shallow region, the idea of filling the bulk UHMWPE with large quantities of wax becomes difficult to justify.

Repeated waxing may still influence ski performance.

It can modify residual wax distribution, remove surface contaminants, change the condition of the mechanically prepared surface and alter the wax present in the effective contact regions.

These effects should be evaluated individually rather than attributed automatically to deep polymer saturation.

The distinction is also important when comparing traditional waxes with alternative surface treatments.

A very thin and well-controlled surface coating may be effective without requiring substantial penetration into the ski base.

The critical factor is how that coating modifies the actual sliding interface and how well it maintains its properties during skiing.

Conclusion: most of the action happens near the surface

Available research indicates that ski wax penetration into UHMWPE is extremely shallow.

Characteristic depths reported for particular wax treatments range from several tens to a few hundred nanometres.

Nevertheless, the amount of wax detected near the surface should not automatically be equated with molecular diffusion into the polymer.

Wax may also be retained in surface irregularities or remain as a thin coating.

The practical significance is clear:

The performance of a waxed ski is determined primarily by the properties and durability of its functional sliding surface, not by the quantity of wax supposedly stored deep inside the ski base.

Understanding this distinction helps us move from the traditional concept of wax saturation toward a more precise understanding of ski–snow surface engineering.ation depth is very small, according to many different research studies the penetration depth is max. 1 microns, 1.000 nano-meters.

Regardless of research study results the value of max. 1 microns, 1.000 nano-meters for wax penetration into the ski base material seems to be very realistic.

SKI GLIDE PHYSICS · RESEARCH SERIES

What Are the Main Weaknesses of Ski Waxes?

PART 2 OF 2

What Are the Main Weaknesses of Ski Waxes? – Part 2: Wax Hardness and Wear

A softer material on a harder ski base

In Part 1, we discussed how wax interacts with the UHMWPE ski base and why the final sliding surface may be heterogeneous.

Another important question concerns the mechanical properties of the wax itself.

Conventional hydrocarbon ski waxes are generally softer than the UHMWPE materials used for racing ski bases.

This difference becomes particularly interesting under cold, hard and abrasive snow conditions.

Why should we apply a mechanically softer material to a harder sliding surface?

And does doing so necessarily improve glide?

How hard are ski waxes compared with UHMWPE?

UHMWPE ski base materials commonly exhibit Shore D hardness values in the range of approximately 60–70, depending on their formulation and measurement conditions.

Hydrocarbon ski waxes can be considerably softer, although their hardness varies significantly with composition and temperature.

For illustration, measurements reported by Kuzmin and colleagues showed the following values:

Material	Shore D hardness
P-Tex 2000 Electra ski base	65.7 ± 0.7
P-Tex 2000 ski base	64.8 ± 0.6
Hard cold glide wax NA8	50.4 ± 3.3
Softer glide wax NA2	12.9 ± 0.8

These values demonstrate that even a wax intended for cold conditions can be substantially softer than the underlying polyethylene base.

However, the numbers should not be interpreted as universal values for all ski waxes.

Hardness also depends on temperature, measurement method and material formulation.

Furthermore, Shore D hardness measured on a bulk material does not directly describe the mechanical behaviour of an extremely thin wax film supported by a harder substrate.

What happens when a softer material covers a harder surface?

When a soft material forms part of the sliding surface, its mechanical response may differ from that of the underlying UHMWPE.

Under contact pressure, the softer material may deform more readily.

Depending on its thickness, temperature and mechanical properties, it may also be more susceptible to scratching, ploughing or abrasion.

However, this does not automatically mean that the entire ski base becomes mechanically softer.

A thin wax film supported by UHMWPE behaves differently from a thick layer of bulk wax.

Its effective response depends on both the coating and the underlying substrate.

It is therefore necessary to distinguish between:

• The hardness of the wax itself.

• The hardness of the original UHMWPE ski base.

• The measured response of the complete wax-treated surface.

These properties are related but not interchangeable.

Why is hardness particularly important on cold snow?

Cold snow can create demanding mechanical conditions for the sliding surface.

As temperature decreases, ice generally becomes harder, although the mechanical behaviour of snow depends on its microstructure and other factors.

Hard, angular snow grains can generate concentrated contact pressures when interacting with the microscopic peaks of the ski base.

During sliding, these contacts may cause deformation, ploughing and abrasion.

A wax that is too soft for the prevailing conditions may be mechanically disturbed or removed more rapidly.

Harder wax formulations are therefore commonly preferred for cold and abrasive snow.

However, the hardest available wax is not necessarily the fastest.

Friction also depends on adhesion, surface chemistry, thermal behaviour, snow morphology and the generation of interfacial water.

The objective is to optimize the complete contact system rather than maximize hardness alone.

Can waxing reduce the measured surface hardness?

Experimental research has investigated how hot waxing affects the mechanical properties of the ski running surface.

Some measurements indicate that wax-treated polyethylene surfaces may exhibit lower apparent hardness than untreated surfaces.

This is an important observation because wax is conventionally applied with the objective of improving glide.

However, a reduction in measured hardness does not necessarily imply a proportional increase in friction.

The mechanical properties of the surface represent only one part of the ski–snow interaction.

Wax may simultaneously improve other characteristics, including interfacial adhesion, wetting behaviour or the resistance of the underlying base to particular forms of wear.

Consequently, the net effect of waxing must be determined experimentally.

A mechanically softer surface can still glide better if other friction-reducing effects outweigh the additional deformation or abrasion.

Wax wear: the sliding surface does not remain unchanged

The mechanical weakness of wax becomes especially relevant when we consider durability.

A freshly waxed ski does not maintain an identical surface throughout its entire sliding distance.

Wax can be progressively removed through interaction with snow grains.

Experimental investigations have demonstrated that wax wear depends on snow temperature, wax molecular chain length and position along the ski base.

In one laboratory study, wax wear was greater on cold snow than on snow close to the melting point.

Differences in wear were also observed between the front and rear regions of the sliding surface.

This finding is particularly relevant for understanding how ski glide changes over distance.

The conditions experienced by the front contact region are not necessarily identical to those experienced by the rear contact region.

The functional sliding surface may therefore evolve differently along the ski.

Can wax protect the ski base despite being softer?

Yes.

A mechanically softer material can still serve as a useful protective or sacrificial layer.

By covering exposed regions of the UHMWPE surface, wax may reduce particular interactions between snow grains and the underlying polymer.

It may also alter the interfacial chemistry and frictional behaviour.

However, the protective effect depends on how long the wax remains in the relevant contact regions.

Once the exposed wax has been substantially removed, the sliding system changes again.

The skier may then experience a different combination of friction mechanisms than immediately after preparation.

This is why the performance of a freshly waxed ski should not automatically be assumed to represent its performance after several kilometres.

The importance of long-term glide performance

Most practical ski preparation comparisons focus on immediate performance.

But a preparation method that is exceptionally fast over the first few hundred metres may not be the best option over a race distance of 10, 20 or 50 kilometres.

For meaningful comparison, we should distinguish at least three characteristics:

1. Initial glide performance: How efficiently does the ski slide immediately after preparation?

2. Wear resistance: How rapidly does the functional surface change during skiing?

3. Performance stability: How much does friction change as the sliding distance increases?

These properties may be related, but they are not identical.

A wax with excellent initial frictional behaviour may exhibit limited durability.

Another preparation method may offer slightly less impressive initial glide but maintain more consistent performance over a longer distance.

Which option is preferable depends on the application.

Conclusion: wax softness is a compromise, not necessarily a disadvantage

Conventional ski waxes are often mechanically softer than the UHMWPE base materials to which they are applied.

Under hard and abrasive snow conditions, this difference can contribute to deformation and wear of the exposed wax.

However, it would be incorrect to conclude that wax application necessarily worsens glide simply because the wax is softer.

Wax can simultaneously provide favourable surface chemistry, reduce particular friction mechanisms and protect the underlying ski base.

The practical question is therefore not whether wax is softer than polyethylene.

It is whether the benefits produced by the wax compensate for its mechanical limitations, and for how long those benefits remain effective.

The best sliding surface is not necessarily the hardest one. It is the surface that provides the most favourable combination of friction, mechanical stability and durability under the actual snow conditions.

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SKI GLIDE PHYSICS · RESEARCH SERIES

What Are the Main Weaknesses of Ski Waxes?

PART 1 OF 2

What Are the Main Weaknesses of Ski Waxes? – Part 1: Wax Adhesion to the Ski Base

Ski waxes: improving glide by modifying the surface

Ski waxes are among the most widely used materials for optimizing the sliding performance of cross-country skis.

Different wax formulations are designed for different snow temperatures, snow types and moisture conditions.

Their purpose is to modify the interaction between the ski base and snow, potentially reducing friction, improving water-related surface behaviour and protecting the base against mechanical wear.

However, applying wax also introduces another material into the ski–snow contact system.

This raises a fundamental question:

How reliably can wax become part of the functional sliding surface, and how consistently can that surface be reproduced?

How does wax interact with UHMWPE?

Modern racing ski bases are commonly manufactured from sintered ultra-high-molecular-weight polyethylene (UHMWPE).

UHMWPE consists of extremely long polyethylene molecular chains arranged in a semicrystalline structure containing crystalline and amorphous regions.

The material may also contain functional additives such as carbon black or graphite.

Conventional hydrocarbon ski waxes generally consist of much shorter molecular chains than the polyethylene chains forming the ski base.

Because both materials have predominantly hydrocarbon molecular structures, they exhibit a certain degree of chemical compatibility.

However, this compatibility does not mean that wax molecules form permanent chemical bonds with UHMWPE.

The interaction is primarily physical.

Depending on the wax formulation, temperature, preparation process and condition of the base, wax can adhere to the surface and may be retained within accessible microscopic irregularities or near-surface regions.

The extent of molecular penetration into UHMWPE remains a separate question that should not be confused with wax retained in surface grooves, scratches or other topographical features.

The ski base is not a perfectly uniform surface

At the microscopic level, a ski base surface is considerably more complex than a flat polyethylene sheet.

Stone grinding, scraping, brushing and mechanical wear create surface features at different length scales.

These may include grooves, ridges, scratches, plastically deformed material and locally fibrillated regions.

The resulting surface is heterogeneous in terms of both geometry and mechanical condition.

When molten wax is applied, it interacts with this heterogeneous surface.

After cooling, scraping and brushing, the wax remaining on the ski is unlikely to be distributed as a perfectly uniform layer of identical thickness.

Some regions may retain more wax than others.

This is especially relevant inside fine structure grooves and around microscopic surface features.

A heterogeneous functional sliding surface

We can imagine the prepared ski base as a microscopic mosaic.

Some areas of the final surface may be dominated by exposed UHMWPE, others by retained wax, while still others may contain exposed additives or mechanically modified polyethylene.

The exact proportions and spatial distribution depend on the material and preparation history.

This mosaic is not necessarily a problem.

A heterogeneous surface can perform extremely well when its properties are appropriate for the snow conditions.

However, it introduces additional variables into the sliding system.

The surface interacting with snow is no longer defined solely by the properties of the original UHMWPE material and its stone-ground structure.

It is also influenced by the nature, amount and distribution of the remaining wax.

What happens during repeated waxing?

Competition skis are frequently subjected to repeated waxing cycles.

Each cycle may involve heating, cooling, scraping and brushing.

Additional wax formulations may be introduced during successive preparation steps.

It would be too simplistic to assume that every new wax application creates a completely separate, permanent layer on top of all previous layers.

Heating may redistribute or partially remove previous wax residues, while scraping and brushing eliminate much of the material applied.

Nevertheless, repeated treatment can influence the condition of the final sliding surface.

Variations in temperature, ironing time, wax composition, scraping pressure and brushing procedure may produce differences in residual wax distribution and microscopic surface condition.

Even when two skis receive nominally identical treatment, their final surfaces may not be perfectly identical.

The important issue is therefore not that every waxing process is inherently random.

It is that the preparation process introduces additional variables that must be controlled if repeatable results are required.

Why does this matter for racing ski service?

A reliable racing ski preparation process should produce predictable and repeatable sliding behaviour.

Ideally, two identical ski bases prepared under identical conditions would achieve closely comparable functional surfaces.

In practice, several factors can introduce variability:

• Initial ski base material and microscopic topography.

• Differences in the condition and cleanliness of the surface.

• Wax formulation and application temperature.

• Cooling conditions, scraping and brushing.

• Residual wax distribution and subsequent wear.

The effect of these variables may be especially important when performance differences between competing preparation methods are very small.

A ski service technician may observe that a particular waxing procedure works exceptionally well on one occasion but produces a less impressive result under apparently similar conditions.

Such observations do not prove that wax adhesion is the cause.

Snow variability, ski characteristics, test methodology and other environmental factors must also be considered.

Nevertheless, differences in the final surface preparation are a plausible source of performance variability.

Wax adhesion and durability are closely connected

The ability of wax to remain on the ski base is also important during skiing.

The functional sliding surface begins to change as soon as the ski comes into contact with snow.

Snow grains can mechanically remove or redistribute exposed wax.

The rate of this process depends on snow hardness, grain morphology, temperature, contact pressure and sliding distance.

A wax that provides excellent initial glide may not necessarily maintain the same performance over a long distance.

This raises another important distinction:

Initial glide performance and long-term glide stability are not the same property.

A good ski preparation method should ideally provide both.

Conclusion

The main weakness associated with wax adhesion is not simply that wax cannot bond permanently to polyethylene.

Rather, it is the dependence of the final functional sliding surface on a combination of physical adhesion, material retention, application conditions and subsequent mechanical wear.

Waxing can improve glide, but it also introduces another material whose distribution and durability influence the ski–snow interaction.

For scientific testing and competition ski service, this creates an important challenge: achieving a controlled and repeatable sliding surface.

The objective is not merely to apply a fast wax. It is to create a functional surface whose properties can be reproduced and maintained during skiing.

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Continue reading: What Are the Main Weaknesses of Ski Waxes? – Part 2: Wax Hardness and Wear

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SKIING WITH A SMILE · FOUR-PART SERIES

The Secret of a Reliable Kick

PART 3 OF 4

The Secret of a Reliable Kick – Part 3: Finding the Perfect Kick Zone

In Part 1, we discussed why the correct ski length, stiffness and geometry are essential for a reliable kick.

In Part 2, we looked at ski base materials and different grip systems.

Now let's assume that we have properly selected skis, a suitable ski base and even the correct kick wax.

Surely nothing can stand between us and a perfect cross-country skiing experience now.

Unfortunately, there's still one little detail.

Where exactly should we apply the kick wax?

And here we arrive at a surprisingly sensitive subject.

Size.

More precisely, the length of the kick zone.

And here, as in many other areas of life, bigger is not necessarily better.