Thank you for airing your success story. About 25 years ago I was working on a 60's Steinway 'D' that had a noticeable flex in the long key sticks. The flex was so great, it felt as if the hammers were checking on the upswing – slow acceleration. I stumbled upon the idea when I smelled epoxy being used on an unrelated project by my assistant. I simply applied the epoxy on the side of all the keysticks. It worked. Since then, whenever I encounter a flexing keystick I find the epoxy is quick and effective.