Maintenance on your front sight consists mainly of keeping it clean and bright. A little information about how fiber optic material works will explain why. True fiber optic rod is composed of a core layer of material that is impregnated with a fluorescing compound that reacts to light. This fluorescing compound is surrounded by a thin sheathing layer that has a different index of refraction than the compound. Ultraviolet light enters through the exposed sides of the fiber. The light is trapped within the fiber because the difference in refractive indexes between the core and the sheath do not allow the light to reflect back out through the sheath. The UV light causes the material in the core to fluoresce and emit visible light out the end of the tube where there is no sheath. The longer the tube, the more light is captured and emitted out the end. One benefit of the physics of the fiber optic is that on a cloudy day you still have lots of UV light available to light up the fiber.
As you can see, the key to the fiber optic functioning properly is the outside sheath. This is what lets in the UV light and then traps it so that it can come out only on the ends. Therefore, it is critical to keep this sheath intact and clean. A dimming fiber optic means the sheath is either dirty and can’t let in as much light or it has been damaged and is not longer able to trap light. Following are some tips to help you keep your fiber optic bright:
1. Keep the fiber as clean as possible but do not do anything that deteriorates the sheath.
2. When you install replacement fiber, take care to keep the sheath intact as much as possible.
3. Stay away from chemicals harmful to plastics such as brake cleaner and gun scrubber for cleaning the fiber and when cleaning your gun.
4. Replace the fiber every once in a while when it gets too dirty to clean, or when the sheath deteriorates. I recommend you replace the fiber before each match just like the battery in a dot sight.
Installation of replacement fiber is an easy operation:
- Remove the broken fiber from the sight.
- Insert replacement fiber from the muzzle end and leave approx. 1/16 inch sticking out (the more you leave sticking out the bigger the dot).
- Melt the end with a cigarette lighter.
- Hold the melted end tight against the sight and cut the end closest to the muzzle, leaving 1/16 overhang.
- Melt the muzzle end of the fiber while holding the fiber tightly against the sight. It is important to make sure that the fiber is snug in the sight with no play back and forth. A loose fiber will break very quickly.
It may be a little more trouble to use a fiber optic sight, but most shooters will agree that the benefits significantly outweigh the extra effort. A good, bright fiber optic sight will help you see the front sight, get you on target quicker, and speed up target acquisition.