Though it cannot be seen by the naked eye, ski wax added to the base of a ski works on a molecular level to reduce the friction between the ski and snow. The central idea is to create a water repellent and protective combination of molecules by adjusting the levels of hydrogen and fluorine, depending on the physical state of the snow. Basic waxes used on downhill skis are hydrocarbon and hydrocarbon wax with fluoro additive.
Hydrocarbon, denoted as CH, is a hard wax that has a higher friction on snow than other waxes, preventing it from wearing down on hard snow. It is an economical wax used by ski racers for training and recreational purposes, notes Swix in its 2009 "Ski & Snowboard Preparation Guide."
Low-fluoro additive is combined with hydrocarbon in what are called LF waxes, or low-fluorocarbon waxes, decreasing friction between the ski base and the snow. It is more expensive than hydrocarbon wax, and is used for training and racing, the Swix guide says.
Hydrocarbons contain carbon and hydrogen atoms arranged in chains of molecules. These molecules make up the most basic component in ski wax. Replacing the hydrogen atom in hydrocarbon wax with more electronegative--and therefore more water-repellent--elements produces a wax that is faster on snow.
Hydrocarbon becomes fluorocarbon when fluorine atoms replace some hydrogen atoms from hydrocarbon. Fluorine, the most electronegative element, is hydrophobic and does not react with water molecules, causing it to have very little friction on snow. The addition of fluorocarbon to a hydrocarbon wax provides it with these electronegative molecules, further reducing the friction between the ski base and snow.
The amount of fluorine added to hydrocarbons varies in ski waxes between high and low, but a wax must contain 3 percent fluorine to benefit from its water repellent nature. Low-fluorocarbon wax contains the least fluoro additives, between 1 and 6 percent, of all fluorocarbon waxes. Wet snow conditions call for high-fluorocarbon wax, according to the Swix guide. Low-fluorocarbon wax, with its less water-repellent nature, reduces friction on harder snow.