night sights question

[andrewjs18]

My CZ-85B came with standard night sights...

My question is...how long are they supposed to glow? I usually hold the sights directly under a lamp for about a minute before I go to bed and they don't seem to last for that long...

[normanvin]

Depends on what type they are. Some lose their gusto as they get older.

[Captain Tuttle]

Tritium sights should glow on their own without needing to be "charged-up" by a light source. Tritium sights last for years but eventually dim out.

If you are using a light to charge your night sights, it's unlikely they are tritium. Hope this helps.

[mikepro8]

If they are standard night sights, (usually Tritium,) after about about 7-10 years they should be replaced. Some last up to ten. I just replaced my bro in laws' night sights on his duty glock. the rear were just about out, the front was still going strong. He's had them on for about 10 years.

[andrewjs18]

whatever comes stock on the CZ-85B...they definitely don't glow on their own.

http://www.cz-usa.com/product_detail.php?id=41

doesn't say on their site.

[LittleRedToyota]

whatever comes stock on the CZ-85B...they definitely don't glow on their own.

those aren't actually night sights, then.

they are more likely the kind of sights people use for daylight IPSC shooting...they gather ambient light and focus it to make the sights very bright in the daylight--making it easier to find the sights quickly. and they will retain some glow after being taken out of the light...but they aren't meant to be used as night sights.

as mentioned above, true night sights use a radioactive material (tritium) to produce their own glow. examples are meprolights and trijicons.

they do fade as the tritium decays (the rate of decay is determined by their half life...so the decay is faster early in the life of the sight and slower later in their life as the decay over time X--which is the half life--is 50% of whatever radioactivity is left at that point. so, over the first half life, the brightness goes from 100% to 50%, over the next half life, the brightness goes from 50% to 25%, over the next it goes from 25% to 12.5%, etc.)

i believe the half life of tritium is around 12 years. so, in theory at least, night sights should be half as bright after 12 years as they were when first manufactured. this is generally more than enough decay that they are not bright enough to be effective anymore.

[andrewjs18]

I guess that's what they are then...

Thanks all for the replies.