I have been reading the forums and trying several techniques with fiberoptic strands and thought I'd just add to this thread to pass along something that ended up working well for me.This started when I read somewhere about using a heatgun to ball up the end of a fiberoptic strand a bit, which helps make a slightly larger glowing ball.
I had to get some fiberoptics to make a right angle turn and hug the wall closely - and since it was open then I had to tape them down or something to make them stay. Glue and tape wasn't working well. So in the end after much experimentation I made a jig, a bit of plastic the same thickness as what I was using with about six holes in it the same size as my strands (and the same size as the hole in my actual prop.)
I fed six wires through, bent them and held them in place, and waved a heat gun over them - and the right angle bend stayed, and I now had shaped strands. (I looked up the properties of my strands and they could take a pretty good bend - and testing them showed no diminished light.) I then clipped the outside part of the strand so just a bit extended outside the wall, and hit those with the heat gun (the jig let me do six at a time without having to worry about damaging the prop.) That made the outside melt and ball up a bit.
So here was the cool part. That ball was too large to fit through the hole! I didn't have to actually glue it! I can still pull it out - get a fingernail under it our push it a bit from the inside and you can pull it out - but it can't get pulled inside the hole.
I was still left trying to attach them to the light source I had which was flat and so no glueing or heat shrink tubing seemed like it would help. So I glued a bit of a plastic drinking straw over the light source. I put heat shrink tubing over the fiberoptic ends - that shrank, and the ends of the tubes did ball a bit again, so they aren't sliding out of the heat shrink tube - and then just slid that little package inside the straw and it's now nicely held in place over the light.
It worked well!