How Skis Are Made
Ski Bases:
Ski bases are made through a process called sintering. This is what allows them to be able to “accept” or absorb wax. Sintering is a manufacturing process where a powder (plastic in this case) is shaped and then using heat and pressure it is bonded together to form a porous material. Because the plastic is never melted the material is porous and thus wax can go into the base’s voids/pores. This is how skis absorb wax. The wax actually changes the properties the base exhibits. For instance a hard wax fills the pores/voids with hard wax and makes the base itself harder. The wax then comes out of the base slowly as abrasive snow touches the bottom of the ski. It takes many waxes to fully “saturate” a ski base so this is why many waxes are needed for new skis or newly stoneground skis. Another implication of having a sintered ski base is that the ski base should never get above the melting temperature when ironing in wax. If the base gets above the melting temperature of the plastic, the pores will close as the base melts together and wax won’t be able to be absorbed into the base.
Inner Ski Material:
Important to the heat of your base when ironing in wax is the inner structure of the ski: the core. Most modern racing skis inner materials are wood, epoxy and carbon fiber as seen in the below images. These heat up moderately fast. However, some skis, namely Madshus, have a foam core making them very light, but also more susceptible to heat damage as they heat up quicker. If you feel the underside of your ski and it’s hot then the base is generally too hot. Places to especially watch for too much heat are the tips and tails since there is less core material to absorb heat.
Snow Types, Temps and Conditions
Snow Types:
When selecting skis and wax it is important to think about the snow you will be skiing on. First off, new natural snow is generally slow as its structure is “sharp” (think of a snowflake) and grabs the ski. Although new snow is “sharp” it is not abrasive. Old snow that has sat for 4+ days after falling is generally no longer “sharp” and its structure is more rounded. This speeds up the ski and is usually in the middle of abrasiveness. Freeze thaw cycles above and below freezing and can lead to transformed snow. Often artificial snow is transformed too. Transformed snow is very abrasive and strips wax off easily. The snow structure is very crystalline, partially ice, and typically very fast. Because durability is usually an issue with transformed snow many times a colder wax may be used.
Conditions:
Along with the type of snow, the temperature and humidity of the snow are also very important. Typically snow temp lags behind the air temp by an hour or two so keep this in mind when looking at the forecast. Humidity is also very important because dry (typically cold) snow causes dry friction (overcome with a hard cold wax and a fine structure) and moist humid snow causes wet friction (overcome with a soft warm wax and a coarse structure, possibly hand structure).
Ski Waxing
Waxes:
In general hard wax is for cold conditions and soft wax is for warm conditions. The best waxes for warm humid conditions are extremely hydrophobic meaning they shed water easily. These used to be made of fluorocarbons, but now non-fluoro waxes have been developed to do the same job. A cold wax in warm conditions is better than a warm wax in cold conditions. So, if in doubt, pick the colder wax (since it is harder, durability will be better too).
Base Hardening:
When using any wax (soft waxes especially) it can be good to wax with a cold wax just before putting on the warm wax. The cold wax acts as a base hardener. A harder base means the wax is harder to get out. Some glide wax cleaners also have a base hardener wax in them.
Stone Ground and New Skis:
Stone grinding is the process of taking a layer off of the ski base and imprinting the base with a new structure. This opens the base for wax again, flattens the base, and brings the base to a brand new condition. With new skis or just stone ground skis the process is the same. A lot of wax needs to be put into the base to “fill up” the base pores/voids. This can take 6+ waxes to make the skis as fast as they should be.
Quotes:
US Ski Team Matt Whitcomb:
“ 'personal best' is still talking exactly about the results in ski races. And in order for us to achieve those, we have to take a step back.
Again, in order to race fast, you have to feel support. And sure, this support comes from coaches; it comes from wax techs; it comes from great training all year. But a lot of this work comes from one’s own teammates.
There’s nothing more rewarding to me than when athletes feel engaged, because they know that the 20 athletes around them… support them.”
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US Ski Team Matt Whitcomb:
“Our philosophy is, we really try and embrace technique differences on our team and throughout the nation.
And while, yes, there are these broad fundamentals that are important to nail, everybody *should* ski differently.
And I think that takes pressure off when you’re watching video of yourself, when you’re striving to improve, to not look exactly like Sophie Caldwell did, or Sadie Bjornsen, or Kikkan Randall, or Andy Newell. You can look like a similar version if you want. But this should look like the best version of yourself. And I think that’s the key to technique.”