Extreme steel 'Velcro' takes a 35-tonne load

For all its usefulness, Velcro hardly inspires excitement. But German engineers have taken inspiration from the mild-mannered fastener to create a version of the hook-and-loop concept with enough steely strength for extreme loads and environments.

A square metre of the new fastener, called Metaklett, is capable of supporting 35 tonnes at temperatures up to 800 ºC, claim Josef Mair and colleagues at the Technical University of Munich, Germany. And just like everyday Velcro it can be opened up without specialised tools and used again.

Conventional hook-and-loop fasteners are used for everything from bandages to cable boots in aircraft and securing prosthetic limbs. Mair thinks his spring-steel fastener is tough enough to be used for building facades or car assembly. "A car parked in direct sunlight can reach temperatures of 80 °C, and temperatures of several hundred °C can arise around the exhaust manifold," he says, but Metaklett should be able to shrug off such extremes.

The fastening is made from perforated steel strips 0.2 millimetres thick, one kind bristling with springy steel brushes and the other sporting jagged spikes.

Metaklett can support maximum weight when pulled on in the plane of the strips, and a square metre can hold a perpendicular load of 7 tonnes, says Mair.