What if there was an iron or titanium wire coated with some sort of rubber/plastic or some synthetic epoxy coating, and then used as string? Wouldn't that make for a super durable and powerful combo? The metal doesn't have to be super thick, just the core. And it could be made so that it's more elastic (cooling the iron slowly after it is cast and pulled through a die). Think about it, iron and other metals are more efficient in elasticity, it means that when you stretch them they come back with the same force. Other plastics aren't as good. A steel ball bounces to 98% of its height dropped, while a plastic polyester ball would do, maybe 60% maximum. Is there anything like this?