An Expert Guide to Ski Materials and How They Impact Your SkiingPublished on 10/24/2021 · 10 min readCurious about what skis are made of and what the effects are of different materials? Read on to find out the answers in this guide to ski materials.
Photo by Henry Perks
I’m here to offer a breakdown of ski materials as a Ski Expert at Curated, someone who’s been skiing for more than 25 years, and who has experience in many different parts of the ski industry around the world. I also have a background in mechanical engineering. Because of this, I have always been very interested in the technical aspects of ski equipment. Getting to test new products and prototypes is one of my favorite things to do, as it allows me to compare the design concept and material choices of the ski with how it performs on the hill.
Parts of a Ski
Let’s start with the basics: the different parts of a ski. Every ski is made up of five major parts that can each be made with a variety of materials we will discuss below. The components are the topsheet, core, sidewall, edge, and base, plus the epoxy resin that holds the ski together. All of these affect the way a ski performs in different conditions, with the core material having the biggest impact.
One thing to keep in mind when considering how these materials act is that the same materials can act differently based on the manufacturing process. An example of this is the Blizzard Flipcore technology, as seen in skis like the Cochise. In contrast to most skis on the market, they are milled to their finished profile before being pressed, versus others that are milled into the correct thickness but flat, and then pressed into tension when the ski is made. In theory, this technique can make the flex pattern of the Blizzard skis more even and predictable.
Topsheet materials have changed over the years, and there are more materials and methods for making topsheets today than ever before. Regardless of the type or method, the main functions of a topsheet are to seal the ski, protect it from water damage, and make it look cool. Some are also used as a structural layer. The main methods for putting the graphics on a topsheet are screen printing, sublimation, and digital printing.
The reason that some skis are designed with a structural topsheet, or a material that does more than just seal the ski and graphic, is either to change the way the ski flexes or reduce the weight of the ski by eliminating a layer. As skis are designed as a whole, the topsheet has a limited effect. It is probably the thing you need to worry about the least when deciding on what ski to buy.
The core is the most important part of a ski’s construction. Almost all skis are made with a primarily wood core. There are several wood varieties used individually or in combination, with the most popular being poplar, beech, aspen, ash, and maple. Other woods that are occasionally used in ski cores are super lightweight wood species such as paulownia, karuba, and bamboo.
The lightweight poplar, beech, and aspen are commonly used in all-mountain and park skis that are meant to be a little more playful and lively. Heavier and more durable woods, such as ash and maple, are common among more aggressive, big mountain skis that are meant to be a little more damp. Super lightweight woods are most often used in skis meant for alpine touring to save weight.
The other key parts of the core are the laminates, which have the biggest impact on the strength and flex pattern of a ski. These include composites like fiberglass and carbon fiber, as well as metal (most often Titanal) and other advanced materials. The most common composite layer is fiberglass because it is strong, light, and one of the cheaper options, relatively speaking. Fiberglass is often used in skis, even if it is not the only type of laminate.
Carbon fiber is a similar material but is significantly lighter, a little more lively, and more expensive. There are two main types of fiberglass and carbon fiber: biaxial braided and triaxial braided. The difference between them is in how many directions the individual fibers are woven. The result is that the triaxial braided material has more torsional strength.
In contrast, Titanal (an aluminum alloy) and some types of fabric are occasionally used in the construction of skis, mainly to help dampen the ski. Although Titanal does make a ski stiffer, the main purpose of the core is to absorb vibration and/or add torsional rigidity, which allows for energy to be transferred more efficiently to the edges of the ski and to make rough terrain or snow feel less rough. It does this by absorbing energy instead of transferring it to the skier.
Another common theme in recent years is to have some sort of lattice structure and air, a specialty material, or a layer removed near the tip and tail of the ski, all with the goal of making the tips chatter less and have a lighter weight. All the materials in the core are combined in a variety of different orientations, directions, places, amounts, and methods of manufacturing to give the ski the performance and flex desired by the design team.
Sidewall Types and Materials
There are limited materials used for sidewalls, including ABS plastic, P-Tex, ultra-high-molecular-weight plastic, and, on rare occasion, wood. There are multiple types of sidewall construction, such as full, micro-cap, capped, and hybrid. Full cap construction skis have a topsheet layer that wraps around the side of the ski all the way down to the edge. This is the cheapest and lightest option, and it also does a good job of preventing damage when skis cross or bump into each other. The downside is less energy transfer to the edge, meaning less edge grip.
A full sidewall ski most commonly uses ABS plastic that is the full height from the edge to the topsheet, going all the way around the ski. Although it is heavier and makes topsheets more susceptible to chipping from ski-to-ski contact, this type is the best at transferring all the energy from the skier to the edge due to the leverage and increased torsional stiffness. Micro-cap sidewalls are a variation of this, where the topsheet wraps around the first quarter of the sidewall where it then meets an ABS sidewall to help prevent damage to the topsheet.
The final type that is becoming more and more common these days is the hybrid sidewall. This is a mix of the full and capped sidewalls in an attempt to get the best of both worlds. It is most commonly done by having the area in the middle of the ski have a full sidewall that transitions to a cap as it gets closer to the tip and tail. This allows for good energy transfer while still keeping the weight down, especially in the tip and tail.
Most ski edges are simply made of steel or stainless steel. Although not part of the edge itself, many manufacturers will also use rubber foil or another dampening layer that goes over the T-shaped teeth and into the core to hold the edge in the ski. This is done to absorb energy from impacts and vibration. Some manufacturers will use a specific hardening treatment for the steel, but the main differentiating factor related to the edge material is how thick it is. The most common width is 1.8 millimeters; however, on some skis, especially those designed for park skiing, they will have a 2.5-millimeter-wide edge for added durability.
The other thing that differentiates types of edges is whether the edge material is wrapped all the way around the edge of the ski or just along the sides and not around the tip and tail. The latter is called a partial wrap edge. This can make the ski lighter but comes with the possibility of a small reduction in durability. Still, the chance of an edge popping out or being damaged is usually more dependent on the overall build quality rather than if the edge goes all the way around the ski or not.
Ski bases are made of an ultra-high-molecular-weight (or really dense) plastic called P-Tex. The only other material commonly used in a ski base is P-Tex mixed with small amounts of graphite and carbon. Carbon is used in high-end race skis to make them faster. It does this by discharging the static electricity that builds up from the ski sliding across the snow, which creates more friction.
There are two ways that ski bases can be made: they are either extruded or sintered. Extruded means the material was melted down and then cut to shape. This type of base is cheaper, easier to produce, easier to repair, and also requires less maintenance (how often it needs to be waxed). However, it is less durable and slower.
To create a sintered base, P-Tex is turned into a powder and then the graphite and carbon is mixed in (if it is to be included). Then, the base is heated and pressed before being cut to shape. A sintered base is more expensive and difficult to make but it is harder, more durable, and absorbs wax better because it is more porous. This type of base needs to be waxed more often, as it is more affected by being left unwaxed than an extruded base is. The last thing to know about bases is when the material is listed on a spec sheet followed by a number, that number refers to the molecular weight. Generally, the higher the number on the spec sheet, the better and more durable the base.
To get the graphics on the base of a ski, companies take two approaches. They either print the graphics on a material that is placed under a clear P-Tex base, or they use different colors of P-Tex cut into pieces to create a pattern. This second method is referred to as a Die Cut base, as the base pieces are cut by a machine using a die.
Multiple layers of epoxy resin are put between the layers of a ski when it is laid down before being pressed. After being pressed, the resin helps to hold all the layers together, add strength, and help the ski keep its profile. The only performance factor this has much effect on is the durability of the flex pattern and ski itself.
There are a couple of innovations in this space. One is that some companies are using a more sustainable and environmentally-friendly resin formula. Another is the use of pre-impregnated composite materials that have resin added and hardened before the ski is pressed — this means the layer uses much less resin, is lighter, and the flex of the ski will stay new for longer before starting to break down. The downside is that skis using this technique are usually quite a bit more expensive. This is in comparison to composites that are still fabric when laid down in the mold, which are then covered with a coat of resin that hardens when the ski is pressed.
I hope this has given you a better idea of the materials, manufacturing methods, and reasoning around the different parts of a ski and the materials they’re made of. As is apparent from all the different options manufacturers can use, there is no one material that is best for each part. All of the material and design choices come together with the shape and profile of the ski to determine the way it performs.
Although some may have more of an effect than others, any one of these decisions can change the way a ski performs, so it is always good to talk to a Curated Expert when buying a ski. We'll have an idea of how all the specifications of any one ski come together and can explain how that will translate to your experiences on the hill.