Their instructions suggested attaching LEDs to the end of fiber-optic light pipe using heatshrink. However, I found this method challenging because light pipe has a low melting point. So I looked for alternative methods to focus LED light into the light pipe.
Here is a quick way to make strands of fiber-optic material light up, without heatshrink. It is a non-permanent solution, so if you want to reuse the fiber optics they can be easily removed. Also, this is one way to use expired sugru.
some Fiber-Optic light pipe strands (so people don't have to buy yards of it at once, I put small quantities for sale at http://www.gadgetcat.com/?product=fiberoptic-lightpipe)
plastic drinking straw
~2" duct tape (black electrical tape would be even better)
3V coin battery for testing
Quick overview of assembly:
Stick an LED and fiber-optic light pipe inside a straw, use expired Sugru to hold the LED in. Wrap with duct tape or black electrical tape to help focus all the light into the light pipe.
Step 1: Cut the (stiff) Sugru
Use the piece of straw to mark the size of the Sugru plug for the end of the straw