I used Dykem layout fluid…It works great to color the strings. Only I made a big mistake… so to save you from my disaster, using this or Sharpie Pens, please read on:
Dykem layout fluid comes in red and blue color… great and you can get on amazon. It also is in a shoe polish type of container with the same type of rounded material top. so you can put on like shoe polish. Great! my friend recommended and said it really stays on and he has fluorocarbon strings like mine.
What I didn’t realize – I should have laid the harp on the floor, and put newspapers under it . why? Well, when tipping the shoe polish container up, with my harp standing up, I tipped it too much, and it ran down underneath where I could actually see, and ran down my soundboard. ugh… then I attempted to take it off, imagine dark blue permanent stain down your harp!!! the mfg said to use acetone to take it off… so I did and with much rubbing it took it off, along with some of the stain and all of the lacquer finish where I rubbed. It is now at a furniture refinisher who will attempt to fix it for me! So the Dykem works, sharpie pens work (magic makers called sharpies) however, lay the harp down on the floor with proper floor covering newspaper and it does work…🙃