What are the main weaknesses of the existing UHMWPE ski base types? – Part IV.

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.

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.

In bulk similar free cavities do exist because the bulk material consists of intertwined molecular chains. It is estimated that wax can penetrate the ski base up to 1 micrometer, thus 1000 nanometers, the deeper you go, the less wax molecules you will - however - find.

Both free spaces in flokati carpet on the very top surface and free cavities inside the bulk material are ca. tens of nanometers large which means there is enough space for wax molecules  but...

If we connect this knowledge about size and distribution of free spaces or cavities in the flokati carpet on the very top surface and in the bulk material of the ski base with the knowledge about how especially competetion skis are prepared (several basic wax layers applied as hot appoach, gliding layers applied as block waxes or powder waxes, top coats applied as liquids or sprays), we need to see / understand that the spatial capacity of free spaces and cavities which was available at the very beginning of the ski service process is consumed very fast and each new layer applied on the ski base creates more and more complex mixture than a new layer.

If we combine these types of knowledge about size and distribution of free spaces or cavities in the ski base and about competition ski service processes with the chemical interaction between PE / carbon black as main material components of the ski base on the one side with waxes and wax-based gliding agents on the other side (chemical bonds between ski base and waxes are extremely weak and waxes need to rely on mechanical retention inside the ski base) it must be absolutely clear to us that existing services processes in combination with existing ski base types cannot create any relyable / repeatable and controlable results.

Combination of the existing ski base types and existing ski service processes cannot result in relyable / repeatable and controlable gliding features on the ski base.

Why no wax chemistry has appeared?

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.

 To make waxes penetrate the ski base, more pre-conditions need to be given:

•  ski base material needs to have free cavities to take waxes
• heat needs to be introduced to increase the mobility of ski base material and liquidize the waxes
• wax filled cavities need to shrink after cooling to retain wax mechanically

·          As you can see the standard liquid waxes where the gliding agent is dissolved in a fast-evaporating carrier do fulfil only a part of one condition needed for a strong mechanical retention = they are liquid…that’s all…

The idea that liquid waxes can penetrate the ski base material due to the liquid status does not work in reality because especially the heat induced effects are completely missing.

To replace the heat approach and keep liquid waxes application as simple as possible, alternatives have been searched for to improve the mechanical retention of liquid waxes and thus their life time.

The clear answer is no-wax chemistry = gliding agents in a carrier which helps to penetrate the ski base.

To penetrate the ski base etching or swelling approach is often used. To fix the gliding agent in and on the ski base special carriers are used which can connect with both PE and gliding agents.

No wax chemistry is the approach how to keep liquid gliding agents application simple and to achieve a reasonable life time of liquid gliding agents… With waxes it is – however – hardly possible, that’s why no-wax chemistry…