Posted by Jacob Huseby on Feb 20th 2023
Graphite Ski Wax | Everything You Need To Know
Graphite Ski Wax | Everything you need to know. By Jacob Huseby
Originally published Feb 8th, 2020, as a response to a question about graphite ski wax. Updated for 2023. Republished since we’re recommending graphite for the Birkie open track events.
To save you some reading: You usually will use Graphite in fresh and cold snow. If you’re skiing below -12.22C° (10F°), it may be worth your while to iron in a layer of BWG (or SGG) before applying the wax of the day. If you want to know why, keep reading… I’m going to begin by explaining how skis glide on snow, and then explain how static can impact skiing performance and finally how a graphite layer can help prevent static buildup.
2023 Update: I will also touch on how graphite acts as a lubricant in dirty snow. The lamellar structure of graphite (meaning comprised of layers) helps repel dirt which can have a big impact on the performance of your skis over the course of a race.
Beneath the boots: How do your skis glide on snow?
To understand why we would use graphite ski wax, we first need to understand how skis glide on snow. The ski bases that you are riding on are made of a special plastic that is more durable, hydrophobic (meaning water repelling), and slicker than just about anything. This plastic is called ultra-high molecular weight polyethylene (or UHMWP if you like acronyms) which is like the thermoplastic polyethylene that you will find in everything from shampoo bottles to traffic cones. When this base is run across the snow, a thin layer of water is formed from the friction between the ski and the snow. This thin layer of water is what allows you to glide.
How dirt impacts skiing performance, and what we can do about it.
Dirt can have a big impact on the performance of your skis. If any dirt is stuck to your ski base, it can disrupt the smooth flow of water tip to tail. Graphite waxes are in the category of “black waxes” which usually contain graphite, or molybdenum disulfide. These materials are used in dirty snow conditions because they are solid lubricants. Solid lubricants refer to inorganic materials with lamellar structure (meaning comprised of layers). The parallel layers that comprise graphite and molybdenum are weakly bonded and shear apart under pressure. In this case “pressure” can refer to your skis encountering dirt. The molybdenum or graphite breaks apart instead of the dirt sticking to your ski base.
If both materials repel dirt, why do we differentiate between graphite waxes and molybdenum waxes? Molybdenum is a superior solid lubricant and is better suited for repelling dirt since it can shear in the absence of moisture. Graphite is used for dry snow because it is a better conductor of static. Speaking of which....
Understanding Static: Where does it come from and why does it affect your skiing?
When skiing on dry snow, the friction between the hydrophobic UHWMP base and the dry snow causes an exchange of electrons. This exchange of electrons is called electrostatic friction or friction electricity and can slow your skis down. Fresh snow is positively charged, and your fancy plastic ski bases make an excellent insulator. By rubbing your ski bases on the snow, they pick up the charge. When skis remove electrons from the snow without a suitable conductor, those electrons will then try to grab back onto the opposing charge protons in the snow, slowing you down. Think magnets, opposite charges attract.
In high moisture conditions, static is less of an issue. This is because humidified air is more conductive than dry air. This conductivity reduces static charges from friction and will reduce the effect of electrostatic friction on your skis. When the air is warm, there is greater space between the air particles for water vapor to occupy. When the air is cold, the air particles are tightly held together and that results in lower humidity. This is because there is less space for the water vapor to float around. It should also be noted that due to the crystalline structure of frozen water, there is air surrounding every single crystal of snow. For the sake of keeping things simple, we can assume moist air would mean moist snow, due to snow being comprised of mostly air.
So, when exactly should you use graphite wax?
Graphite not only helps prevent electrostatic friction in dry snow conditions, but can help keep your skis clean by preventing dirt from sticking to your ski bases. You should use graphite wax when the snow is dry, fresh, and cold. You can also use graphite when the snow is dirty. However, often molybdenum is a superior option to graphite if your only goal is preventing dirt accumulation.