Getting technical

How easy is it to make a pair of skis? As Stephen Wood found out, there's far more to the process than meets the eye

Every major US ski manufacturer has exported its production to the Far East. The last to move was K2, and since 2003 its skis have been manufactured in China. Previously the production line was in Vashon Island, Washington State, where since 1964 the two Kirschner brothers (hence the name K2) had made skis - and, prior to that, animal cages.

One day in 1993, work at the Vashon Island plant was disrupted by the arrival of a group of British journalists. Wearing protective clothing and tooled up with purple resin, they had come to make skis - one pair each. As beginners, they hit a few problems: one wrote later in the Financial Times that "up to my armpits in purple gunge, I had serious doubts about whether the soggy objects I was toying with would ever turn into anything, let alone brand-new skis".

In the event, the finished Dark Star K2 skis with which the writer was presented, their graphics inspired by the rock band Grateful Dead, proved to be sleek and elegant. Despite suspecting that a behind-the-scenes switch had been made - his soggy mess exchanged for a product of K2's finest craftsman - he proudly made a display item of his skis when he returned to the UK.

Creating skis may not be as easy as the experts make it look, but a visit last autumn to the headquarters of Salomon, the world's leading manufacturer of winter-sports equipment and by far the most innovative, did give me the impression that I could knock out a pair of X-Screams if I had to. It appeared no more difficult than making a rather fancy sandwich. And nowadays there's no need to add purple gunge.

Salomon is based near Annecy, in the foothills of the French Alps. The company does its research there, spending five per cent of turnover on R&D and registering about 90 patents per year. In the research workshops are prototypes of Salomon racing skis composed of 20 different layers of materials, including a core created from bonded wooden strips like some esoteric plywood. But it is 25km down the road, at a factory in Rumilly, where most Salomon skis are manufactured. Only the cheaper, entry-level and rental skis - 200,000 pairs of them - are made elsewhere, at a Fischer plant in Austria.

What lies beneath the skin of the kind of ski that you and I use? Layers of structural and bonding materials, compressed together. The core of the ski is most commonly made from polyurethane, although as one Salomon executive put it to me, "core materials have gone round the block". Wooden cores were traditional; but other, more fashionable materials - metal, plastics, carbon-fibre - progressively displaced them, with glass-fibre and polyurethane (PU) foam becoming the norm. Now wood is again the core of choice for high-quality skis because it offers the ideal combination of liveliness and damping. Top-of-the-range Salomon skis have a combination of wood and PU elements at their heart.

The other layers placed into the aluminium moulds at Rumilly - where 500 people make 500,000 pairs of skis and 40,000 snowboards per year - are glass-fibre and resins, aluminium and/or titanium, carbon fibre and bonding strips, the last a more convenient form of adhesive than purple gunge. With Salomon's "monocoque" design, these elements (plus the graphics used to decorate the ski's top face) are set within a casing that has a very shallow "u" shape, and closed in by the metal edges and ski base. The whole assembly is baked at 140-160C for seven minutes. When the ski emerges from the oven, the bonding layers have melted and then hardened to unify the structure.

The exact recipe for this sandwich depends upon the performance demanded from the ski. The most obvious variations lie in the short, reinforcing layers used to create a "platform" beneath the boot binding: the greater the reinforcement, the more rigid and "lively" the ski will be, and the faster it will switch from edge to edge.

Some adhesive has often leaked out of the side of a freshly cooked ski, looking like the white of a fried egg. Once this has been ground off, the focus of attention is then the ski's metal edges.

Generally, ski-making at Rumilly is a fairly labour-intensive process, and trolley-intensive, too: women in white lab-coats work individually at their work-stations, and skis in different stages of production are wheeled from one to another. The only mechanised, production-line process is edge-grinding: dull skis go in one end and come out with bright and shiny edges at the other.

If making skis seems simpler at Salomon than it was more than a decade ago at K2, that is probably thanks to production design. The process is now easy on the workforce and on the machines. The grinding machines don't have to grapple with the upward curve of the front of a ski: the raising of the tip - forced upwards in a press and then heated and cooled so that the bonding "fixes" its shape - comes later, as the final part of manufacture.

That all sounds pretty straightforward, doesn't it? You and I could make a pair, right? But they'd probably be a trophy to hang on the wall: we wouldn't risk skiing on them.

Salomon: 0800 389 4350; www.salomonsports.com