So that is essentially what I did with the "Kubickenbacker" build. I did fairy lights and mixed glow powder into epoxy and made all the markers like that. The hope, as you said, being that the LEDs would charge the glow powder inlays...I haven't done it in a build yet, but I'm going to try fairy light LEDs under the fretboard right behind luminlay dots. My hope is they will be charged from the inside and will glow externally, or can be just lit up and enough light would pass through. Of course I'll share once I've tried it. I also have a variety of coloured glow powders which have worked well in my tests.
It didn't really work that great.
From what I've gathered, in order to make something remain glowing longer, you really need to maximize the powder. In other words, a shallow inlay of powder and epoxy won't work as well as a deeper one. And the deeper and more concentrated with powder you get, you obviously lose translucency.
And as bright as the fairy seem, they don't really charge the powder well. I'm double checking it now, as I still have the carcass of that bass in the shop. The 6V source that lights the LEDs does a good job making the fronts bright (white dot inlays) and the sides suffer from varying degrees of powder, as well as some needed to be redone, so they were inconsistent, but visible.
Here's with LEDs on:
After a couple minutes on, flipped off:
By comparison, here's them charged for 10 seconds with a 1000 lumen flashlight (external, of course):
The basic thing seems to be, if you want powder to charge, the LEDs need to be VERY bright. If that brightness was in a neck inlay, it would likely be blindingly distracting unless the glow powder dulled it enough. But at that point, it may almost end up opaque.
Fairy lights as normal LED inlays though, that works great! I did my other basses with no glow, just a touch of white paint in the epoxy to make it visible and translucent. With consistent depth in mounting, they are awesome.
It would likely work with glow to make the epoxy translucent and you could carry a small light or laser pointer or something to charge them, should you need the subtle light and not LEDs in that moment.
Those are my findings at least. I wouldn't hate attempting fiber optics instead some day, but haven't found a source for that. Maybe I should for this?
