PDA

View Full Version : Do night sights wear out?


kuhjäger
12-29-2007, 8:18 PM
I purchased an old sig, and I noticed last night that the sights had a slight glow to them, meaning they were night sights. However, the glow was so slight that I was wondering if it is possible for night sights to fade over time.

I imagine that due to the fact that since they use tritium as the primary agent in them, they should wear out, but I am not sure how long that takes.

CSACANNONEER
12-29-2007, 8:19 PM
Yep. They are always fading. They're radioactive and have a half life.

ajl2121
12-29-2007, 8:22 PM
yes..my usp .45, manufactured is 2006, has meprolight night sights and they are gettting dimmer by the second. They will probably be usable for another 10 years though..It's called Trititum, a radioactive substance, with a half life around 10 years I believe...It was also used in Spider Man to power the octopus.

StraightShooter
12-29-2007, 8:22 PM
Yeah, the tritium is radioactive and decomposes with a half life of around 7 years. This means that in seven years it will be half as bright. You should be able to get those replaced but it will probably cost around 100 bucks.

kuhjäger
12-29-2007, 8:24 PM
Yeah, the tritium is radioactive and decomposes with a half life of around 7 years. This means that in seven years it will be half as bright. You should be able to get those replaced but it will probably cost around 100 bucks.

Wow, this is an old gun then. They only glow a little bit. I suppose I should invest in some new ones then.

bluestaterebel
12-29-2007, 8:31 PM
mine barely glow 10+ years

Fjold
12-29-2007, 9:25 PM
Trtium has a radioactive half life of 12.3 years.

Which means that in 12.3 years half of the tritium will have decayed (changed) to helium.

Ironchef
12-29-2007, 9:29 PM
How is the tritium night site done? Is it a topical application to the sight's holes, or is it concealed in a tube or behind a screen?

I just got an H3 watch that has the tritium tubes and they were guaranteed to retain their glow for 25 years (being factory fresh). Are the tritium night sights given the same quantity and application as the tritium watches are?

Fjold
12-29-2007, 9:34 PM
Night sights are typically just tritium applied over wet paint. Your watch probably has a lot more tritium applied so that even after 12 years it has enough left over to still glow.

Your crystal covers the tritium so you don't have to worry about exposure to the radiation.

Tritium decays with a low energy Beta particle that is not even strong enough to penetrate your skin. Radiation poisoning due to tritium is typically due to inhaling it or ingesting it.

xenophobe
12-29-2007, 9:52 PM
Night sights are typically just tritium applied over wet paint. Your watch probably has a lot more tritium applied so that even after 12 years it has enough left over to still glow.

No. Tritium is a gas, and it is encased in small glass vials, and those are inserted into a particular sight and sealed in with an epoxy.

kuhjäger
12-29-2007, 9:59 PM
Night sights are typically just tritium applied over wet paint. Your watch probably has a lot more tritium applied so that even after 12 years it has enough left over to still glow.


If I remember correctly that was the process to apply radium to watch dials and the like.

And another poster mentioned that Tritium decayed into helium, but that can't be possible, as Helium has periodic number of 2, which would mean that the triium atom gained a proton.

Astig Boy
12-29-2007, 10:19 PM
How is the tritium night site done? Is it a topical application to the sight's holes, or is it concealed in a tube or behind a screen?

I just got an H3 watch that has the tritium tubes and they were guaranteed to retain their glow for 25 years (being factory fresh). Are the tritium night sights given the same quantity and application as the tritium watches are?

They are said to be the same, regardless of how big or small the amount of tritium is. Only a hand full of watches now use Tritium, MTM is one...they state half life at 10-12 years, and full life at 20-25...meaning it will be completely out by ~20 years. And I dont know anyone who uses one watch that long unless its a timeless piece like a Rolex. Tritium in watches is a great idea IMO...you can look at your watch any time of the night and still be able see what time it is.

tophatjones
12-29-2007, 11:37 PM
If I remember correctly that was the process to apply radium to watch dials and the like.

And another poster mentioned that Tritium decayed into helium, but that can't be possible, as Helium has periodic number of 2, which would mean that the triium atom gained a proton.

Tritium (2 neutron, 1 proton) undergoes beta decay into Helium 3 (2 proton, 1 neutron), which is an isotope of He. During beta decay, a neutron is converted into a proton, while an antineutrino and an electron are emitted.

lt.hanley
12-30-2007, 11:20 PM
Have you looked at the sights ? Most of them will
have a date on them and you can figure how old
they are.

bohoki
12-30-2007, 11:36 PM
nope they just turn into day sights

TonyM
12-31-2007, 12:10 AM
As everyone said, yes, they will eventually not glow.

The original Trijicons from my Glock 23 manufactured in 1991 were very dim in 2006. They were fine in very dark situations, but the glow was barely visible in "almost dark" environments, so I replaced them.

Pretty good life for an $80 part, if you ask me.

CaliGunOwner
12-31-2007, 3:12 PM
Yes, they do wear out...typically from the 10-12 year point. Some will have dates stamped on them so you know how long they've been in existence.

BaronW
12-31-2007, 6:18 PM
Also it's not the tritium itself that glows, that beta radiation excites a coating on the vial (phosphorous, I believe) to emit light.

It's been a while since AP Chemistry, but I believe an electron in phosphorus is excited by X amount of energy, but it can only be excited to a discreet state of +Y energy, so a photon is emitted with X-Y energy (and that determines the wavelength).