Interesting - thanks for posting. I've been looking at using guitar strings - which look extremely similar. The larger sizes have a nickel wire wrapping and have a spring steel core so not very flexible but once bent into shape it holds it's shape very well. Still cheap and easy to purchase ( ~£1 a string from any music shop) so always worth having a variety of sizes in stock. I have tried sleeving it with heat shrink tubing to give it that rubber hose finish but unfortunately the heat shrink wall thickness is too great and you loose all the corrugation. So still work in progress.