The eccentric engineer: how an unsticky glue took a decade to finally stick

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 they were facing, not flat on. But there was one very disappointing problem. Silver’s glue was not very sticky.

In fact, it was so unsticky that, far from holding aircraft parts together, it could only hold a couple of sheets of paper together. Not only that, but even they could be easily peeled apart without damaging the surface. This clearly wasn’t suitable for the aerospace industry, so was it just a waste of time? Silver felt not and, far from giving up on his unsticky glue, he set about a six-year campaign to find a use for it.

Progress, however, was slow until 1972, when Silver had the idea of putting the glue into a spray, which could be used to coat the backs of photographs for placing on display boards. The glue would be strong enough to hold them in place, but the photographs could be repositioned as needed, as the low-tack adhesive remained ‘sticky’ even when peeled and replaced, and didn’t leave a residue.

Having received a patent for his invention, Silver began demonstrating his glue to his colleagues at 3M but was disappointed with the results. Try as they might, no-one could think of anything else to do with the unsticky glue.

It was Arthur Fry, a chemical engineer from another division of 3M, who came up with the solution. Having attended one of Silver’s enthusiastic talks he was reminded of a problem he had which this glue just might solve. Initially the talk hadn’t affected him more than any of the others, but suddenly it came back to him as he sat in church on a Sunday, listening to a, frankly, less than thrilling sermon.

It wasn’t the sermon that was Fry’s problem, but the hymns. Fry sang in the choir, and his hymnbook was filled with paper bookmarks so he could quickly turn to each hymn. The problem was that when he opened his book to sing, the other bookmarks would slide around or just fall out altogether, leaving him standing in a pile of confetti. What he needed was something to keep the markers in place that was strong enough to stay still, but weak enough to be peeled off afterwards without damaging the book.

The following week, Fry asked for a sample of the glue from Silver and painted it on to one edge of small paper bookmarks. This seemed to work well, but it was when he needed to leave a quick note for his boss that the value of the idea finally dawned on him. Sticky notes, with a pressure-sensitive adhesive that didn’t leave a mess but could be posted anywhere, would be invaluable. Or so he thought.

It would be another three years before Silver and Fry’s invention would hit the shops. Firstly, the management still didn’t have a lot of faith in an unsticky glue, whatever you might attach it to, and secondly, having persuaded them, after they noticed everyone in 3M wanted some of their sticky notes, the manufacturing at scale of the notes proved problematic and expensive.

Finally, in 1977 the Press ’n Peel notes went on limited sale and the results were… disappointing. Fortunately, 3M didn’t give up on what was now getting on for a 10-year campaign. The following year, the firm tried giving free samples direct to customers all over America in what became known as the Boise Blitz because of its launch in Boise, Idaho. Ninety per cent of those who tried the product said they’d buy it.

The next year 3M launched its final product – the Post-It Note – across America and the rest is stationery history. That year the team who developed the note received 3M’s Golden Step Award for new products with significant profitability. It won again the next year, and Silver and Fry were later inducted into the National Inventors Hall of Fame.

The note rapidly became one of 3M’s best-selling products and even in a digital age it still produces 50 billion a year.