Looking at the color booklets and online advertising of leading ski producers, one would think that it’s all super advanced 21st century tech, fantastic materials, robots, nano technologies, etc. It’s true – partially. The real secret of perfect ski glide is, however, in skilled manual labor, massive experience in production and constant testing of the product.
Those are my impressions from visiting a factory of KSF Sport Oy, which produces legacy ski brands known the world over: Karhu, Yoko, and Jarvinen.
The most important conclusion I’ve drawn: there is no huge difference in production methods and materials used in top racing ski, suitable for elite, and the second- and third- tier ski that are quite a bit cheaper – and that was a surprise. But let’s go inside the factory and look at the actual process:
The factory is located in Kitee, Finland – naturally, on the Karhu street. Here only a dozen or so workers are producing some 50,000 pairs of skis a year
The graphic tape bearing the logo ( Yoko, Karhu – or made-to-order for custom ski) is being printed by this huge machine…
…and another machine cuts the tape into strips.
This is how the current model year looks like. From bottom to top: Volcan, top racing ski; much-talked about DP Carbon for doublepoling; Karhu Bear Skin Pro ( with skin of course); Spectra Optigrip.
And now let’s get to the core of the matter. Top ski models are made, it turns out, with extra light, very durable – and super expensive – honeycomb aramid material. The race skis demand maximum stiffness with minimum weight – so the honeycomb core is used along the whole length of the ski except the very tip.
The simpler models’ cores are made with either a combination of honeycomb and polyurethane or polyurethane-only – heavier, but significantly cheaper.
Good ole’ wood is being used as a core for backcountry and junior skis.
This pressing machine bonds big sheets of honeycomb aramid and polyurethane with layers of fine quality plywood.
That’s what the bonded sheets look like. The honeycomb core stiffness is already high, while polyurethane ones are being reinforced with an extra layer of plywood. The top skating and doublepoling models are further reinforced with a layer of high modulus carbon fiber – the process I was asked not to film.
At the next stage, a milling machine cuts the sheets into actual ski cores according to desired weight and camber profile.
Here we arrive to one of the crucial stages in ski production – the choice of the material for the ski gliding surface. Most if not all modern ski surfaces are made of UHMWPE or ultra high molecular weight polyethylene – but there is now a huge choice within that category with specific gliding properties. KSF Sport is using fluorinated UHMWPE produced by the Austrian firm Isosport for its racing ski while the rest of the models get UHMWPE from the German Okulen. These rolls of polyethylene will become ski gliding surfaces very soon.
The last bit before the Big Bake Off begins – adding the tip made of ABS plastic.
Now all the basic components of the future ski are being permeated with epoxy resin to completely seal the layers together – and are prepared for the mold press.
The ski are being born! See those yellow supports? That’s how the main characteristics of the ski are being programmed – camber, weight, etc.
The molding of components is achieved by a combination of heat(76-80 Celsius) and high pressure.
END PART 1. STAY TUNED FOR PART 2 WHERE WE WILL TELL YOU WHAT HAPPENS TO (SOON TO BE YOURS?) SKI AFTER THEY HAVE BEEN “BAKED”