So i have two long guns with the front sight a fiber optic. It's the kind that is like a small piece of spaghetti. So it's not night sight it's not a night glow. It's just a sporting front sight.

 

What do you do with these things over the years? Do they fade? Are they supposed to fade? Do they actually produce a glow or do they just capture light better. ?

They just offer high visibility in light.  They do crack and break, but it is very easy to insert a new piece of fiber.  Dawson has a good video of how to do it on their site.

They do not produce their own light or have an inherent source of light that can fade over time.

 

They do capture ambient light and "focus" (for the lack of a better term) the light they capture to the ends of the fiber making it appear brighter.

 

If they get dirty, scratched, cracked, etc... they will appear dimmer as the amount of light they can "absorb" to focus decreases. When that happens they can be easily replaced. As Howard said, there are plenty of how to videos online.

Front sights that are plastic that pick up ambient light have been around since 1955 when Ithaca introduced their Raybar front sight. It was a tube of clear red plastic that was held in place by a brass frame. 

 

 

The modern version today that is billed as fiber optic offers a more concentrated light when viewed by the shooter.

 

Some shooters prefer specific front beads, be it a Bradley-style white bead, German nickel silver bead, brass bead or a genuine ivory bead. 

Thanks Y'all