I need to find something that I can wrap around the coil of a bottle radio (image below) to keep the magnet wire from unwinding. Lacquer is messy and time-consuming. I'm hoping there is a translucent tape that I can use? Someone suggested using Kapton tape, but it's very expensive and a bit overkill for my application. Maybe I can find a generic roll on ebay. I'm going to be showing how to make crystal receivers to kids (ages 7-11). I'd rather not use lacquer (fumes and drying time). Suggestions?