Step 10: Attach the fiber optics
Over-heating the fiber optics can cause them to melt – so if you have some spare heat shrink tubing and LEDs, it can be good to practice the fiber optic attachment technique before trying it on LEDs that are already sewn to the ribbon. Just put together a bundle of short/scrap pieces of optical fiber, and use them to get a feel for how long you can heat the whole assembly before you should move the heat gun away.
Carefully strip the sheathing off of your fiber optic bundle
Use a hot knife or wire cutters to cut a variety of lengths of optical fibers, from about 6″ to about 2′ (or longer, if you like). If you have a hot knife, that’s the preferred method for cutting the fibers – but some light degradation is acceptable, so wire cutters will certainly do the job.
Gather a bundle of cut fibers approximately 5mm across, aligning them so one end is flush
Dispense a small amount of clear silicone adhesive onto the tip of an LED, in the heat shrink tubing – enough to cover the LED with a 1-2 mm thickness of adhesive.
Insert the flush end of the fiber optic bundle into the heat shrink tubing, pushing the ends tight to the LED surface as much as possible.
Use a heat gun to carefully shrink the tubing around the fiber optic bundle. Keep the heat gun moving – focusing the heat in one spot for too long can cause the fiber optics to melt.