James Capper at Yorkshire Sculpture Park

Tucked away behind a door in a wall at Yorkshire Sculpture Park is what they call “the yard”. It’s full of equipment the park uses to shift sculpture around. But for the past few weeks these tractors and forklifts have had a strange new bedfellow: a bright yellow earth-mover/digger that has legs where you’d expect to find wheels or tracks.

The three-legged “Tread Toe” (2010) is the creation of the London-based artist James Capper. It’s one of a trio of large-scale “walking” sculptures that form the centrepiece of a show of his work that opens this weekend at the park. For the next few weeks Capper will be on hand to show off “Tread Toe” and its fellows, “Midi Marker” (2012) and “Exstenda Claw” (2012), on YSP’s expanse of lawns and fields. Indoors, meanwhile, in the Bothy Gallery, drawings, models and films highlight the fact that, while some Capper machines can walk, others can climb or swim.

“Sea Light” (2009) is one of the swimmers, a floating wind turbine that was moored on the Thames for a time in 2010. It’s the first thing I notice when Capper greets me at the gate of his south London studio.

In its partly dismantled state “Sea Light” is a bit of puzzle, but inside, in a space that looks more like a motor mechanic’s workshop than an artist’s studio, all becomes clear. “It’s designed for gale-force winds,” the artist explains, as we watch a film of it gusting about on a barge as it is taken down the river to be installed near Tate Modern. The crew lower “Sea Light” on to the water, then one of them jumps aboard. “He didn’t think twice,” says Capper delightedly. “I’d had it in the studio with all these things I consider sculptures ... but they see it as a piece of industrial equipment!”

Capper’s sculpture is indeed both art and machine. Art offers him the freedom to explore ideas in a way that engineering would not, he says. Yet he’s determined that his machines should function mechanically every bit as well as the real thing.

Up in Yorkshire, I watch Capper put “Tread Toe” through its paces as the show is being installed. While it’s every inch a machine – self-powered, with a steel chassis and a central, telescopic, hydraulic leg – there’s a hint of the animal about it too. As that central hydraulic foot takes the weight and propels it forward, Eadweard Muybridge’s pictures of a horse in motion come to mind.

Capper is constantly on the lookout for organic models that might inform his designs. “Midi Marker”, for instance, moves by digging its claw-like feet into the ground, while a central column expands and contracts like a caterpillar to push it forward. “I’ve been buying books on the anatomy of spiders to see how their joints work and whether that knowledge could be built into a machine,” he says. In the studio, he digs out a book to show me a walking machine based on a cow that a third-century Chinese commander invented to transport rations, and hunts for a film of the US military’s Big Dog robot on YouTube.

Machinery and engineering have gripped Capper’s imagination since childhood. As a boy growing up in a village in southeast England, he persuaded the local mechanic to employ him on Saturdays. “I’d be wrenching stuff out of scrapped cars for projects I was doing at home – a pump to make my own hydraulic system, a battery so I could have lights in a treehouse.” By his late teens, he’d learnt to weld, then charmed his way into the workshop of some steel fabricators to learn the tricks of their trade.

He toyed with being an earth-moving machinery designer, but his parents, a teacher and a builder, were adamant he should go to art school. As a student at the Chelsea College of Art and Design, he was initially inspired by the work of Anthony Caro and David Smith to make abstract sculpture, but soon stopped, feeling he wasn’t “being serious”. “I felt I wasn’t being honest with myself. I had all this real-world engineering knowledge. I started making machines.”

Then he had to decide whether it was the aesthetics of the machines that mattered to him or what the machine could do. “It’s become a fusion of everything,” he says. All aspects of any machine he makes are part of the work of art.

Dotted around Capper’s studio are racks of his so-called “Ripper Teeth”, fiercely sharp-looking hooks that, when attached to the arms of his machines, can perform with surprising gentleness. He organises his sculpture by function – earth-marking, carving, offshore – and the “Ripper Teeth” are the versatile building blocks of much of what he does. Laid out on the gallery floor in Yorkshire, these massive dark curls of steel are beautiful objects in their own right.

At 25, and three years out of college, Capper’s teenage experiences still feed strongly into his thinking. “I’ve got the swing of how to run a workshop,” he says. “There’s art for art’s sake, but this is serious. I am as serious as [a village farmer], who’d look at a seed drill and if it wasn’t working properly, take it apart. For him it was a way of life, but he was very much like an artist. He was a problem-solver – but at art school there wasn’t too much problem-solving going on.”

As ideas for wind turbines, walking ships and floating oil rigs spill out of Capper, he’s hoping that in Yorkshire people will see fragments of ideas for addressing the planet’s problems. But does this mean that he is an engineer rather than an artist? No. Ever since Marcel Duchamp’s readymades, what we call art has been about context as much as aesthetics. Capper is a conceptual artist, certainly, but he’s more: unlike so many artists today, he makes his machine-sculptures himself.

“I like the idea that I can be a rough-cutter, creating pathways,” he says. “A good artist’s work should say to people: look at this because it might change the way you think.”

‘James Capper: Divisions’, Yorkshire Sculpture Park, to April 14. ysp.co.uk

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