Sometimes the engineer-inventor knows exactly what they’re after, but it’s always important to keep your mind open enough to see a different use should it present itself. This is particularly the case if the thing you’ve invented simply doesn’t work. That’s the situation Spencer Ferguson Silver III found himself facing in 1968.
Silver had a very definite plan when he started out his work as a chemist at the Minnesota Mining and Manufacturing Company (now known simply as 3M). His task was to create a pressure-sensitive adhesive strong enough to be used in aircraft construction. The rigours of flight, a life outdoors, ultraviolet radiation, high altitude and extreme temperature variations means that it would require a remarkable glue to hold a plane together.
Silver had come up with a remarkable adhesive. His glue was rather clever (for a glue), being formed of tiny spheres of acrylate copolymer that would stick only where they were at an angle to the substrate...