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Dirtbiker
01-15-2010, 9:24 AM
I just bought a pistol with night sights. How long can I expect them to last?

himurax13
01-15-2010, 9:30 AM
I know the Green Trijicons are supposed to have a 12 year life and the yellow ones are around 5 I think.

Citadelgrad87
01-15-2010, 9:38 AM
I have some Trijicons on a Sig from 1991 or so. They are visible, but VERY dim compared to newer sets on other weapons.

YMMV< but I think around 10 years before the loghts are too dim.

johnny_22
01-15-2010, 9:48 AM
We have a Tritium "EXIT" sign at work, installed 12 years ago. Still as bright as the first day.

GunNutz
01-15-2010, 10:17 AM
Depends on which color, and it has to do with the decay of the tritium. Green is usually 12 years, red and yelllow are 7 and 5 but I don't remember which is 7 and which is 5. If you go to trijicon's site, you can get a better idea.

Dirtbiker
01-15-2010, 10:19 AM
Thanks for the info.

SexualChocolate
01-15-2010, 10:59 AM
I have a set of Meprolights on my Glock 27 that I put on back in 2001, still as bright as the day I bought them.

creampuff
01-15-2010, 11:08 AM
Depends on which color, and it has to do with the decay of the tritium. Green is usually 12 years, red and yelllow are 7 and 5 but I don't remember which is 7 and which is 5. If you go to trijicon's site, you can get a better idea.

That's odd. You are right, the website says orange sights are guaranteed for 5 years, and green/yellow for 12 years. But the half life of tritium is always the same 12years. (Nerd alert), remember radioactive half life is the time it takes to decay to 1/2. So in 12 years only 1/2 the tritium atoms will have decayed.

Wonder why orange is only for 5 years???

slickman
01-15-2010, 11:08 AM
From the Trijicon website

Trijicon offers the choice of yellow or orange lamps in the rear sight only. We always keep the front sight green because it is the brightest and longest lasting of the colored tritium. It is also the color with the most contrast from muzzle flash. Green and yellow sights are warranted for 12 years. The orange lamp only carries a 5 year warranty.

ETA: Creampuff beat me to the punch in posting

MasterYong
01-15-2010, 11:10 AM
I've seen some web sites that claim they retain their light for over 70 years. I'd imagine that they don't just magically turn off after that time, however, so it would be a slow dimming effect.

The good night sights also have paint around an inset tube of gas, so even if the "lights went out" on your sights you'd still have standard dots.

creampuff
01-15-2010, 11:17 AM
I've seen some web sites that claim they retain their light for over 70 years. I'd imagine that they don't just magically turn off after that time, however, so it would be a slow dimming effect.

The good night sights also have paint around an inset tube of gas, so even if the "lights went out" on your sights you'd still have standard dots.

12 years 1/2 brightness, 24 years 1/4 brightness, 36 years 1/8th, 48 years 1/16th, and 60 years 1/32nd, and you get the point. Radioactive decay, will always be the same.

I agree about how important the white inset is; that's why I like Meprolight over Trijicon. (But it looks like based on Trijicon's website, that they have improved their inset)

Dirtbiker
01-15-2010, 11:32 AM
I ask because I've seen a few pistols for sale on the boards and many say the lights are dim. I find that strange since some claim their weapon is only 2-5 years old. Maybe the sight were bought used or the gas leaked out?

elSquid
01-15-2010, 11:42 AM
That's odd. You are right, the website says orange sights are guaranteed for 5 years, and green/yellow for 12 years. But the half life of tritium is always the same 12years. (Nerd alert), remember radioactive half life is the time it takes to decay to 1/2. So in 12 years only 1/2 the tritium atoms will have decayed.

Wonder why orange is only for 5 years???

Tritium doesn't give off visible light; when it decays it emits electrons. The electrons excite phosphors which in turn generate the light. So the different times are probably dependent upon the properties of the given phosphor.

-- Michael

creampuff
01-15-2010, 11:49 AM
Tritium doesn't give off visible light; when it decays it emits electrons. The electrons excite phosphors which in turn generate the light. So the different times are probably dependent upon the properties of the given phosphor.

-- Michael

Thanks..that makes more sense.