Home Forums Hunting & Shooting Hunting Optics Does the nitrogen really leak out of scopes in about a year?

I've never seen him state that or anything close to it. Maybe you should get your facts straight before quoting someone like John Barsness to validate your BS.

Let me clear this up.

No, I never stated anything like 140 degrees or 5 minutes--but I have written about dunking a scope in warm (not HOT) water to see if it ALREADY has a faulty seal.

This is done in water that feels pretty warm to the touch, but not uncomfortable. The temperature is probably around 100 degrees, and won't harm the seals in any scope.

The warm water heats up the gas inside the scope, whether atmosphere, nitrogen or whatever. If the scope does have a faulty seal, the gas will start leaking steadily from the seal. Once that occurs, the scope should be removed from the water. Because the gas is pushing outward, no water enters the scope.

By the way, scopes are filled with nitrogen (or argon, or whatever) just to be sure there's no atmospheric moisture inside when they leave the factory. The nitrogen is expected to bleed off eventually, though obviously not all will leave the scope. But if the seals remain tight they prevent moisture from entering the scope, even after some of the nitrogen bleeds off.

The purpose of dunking the scope in warm water is to heat the nitrogen gas in the scope so that it expands and if there is an improper seal somewhere you will see bubbles coming up in the warm water. John Barsness relayed that one in his optics book but like anyone telling a good story some feel the need to add excitement to the original thought or process. John specifically stated that you place a scope in warm water and if you see bubbles continue to rise for more than 10 seconds, you have a leak. I took the liberty to confirm this with Barsness after seeing the boiling test outlined by Eremicus many, many, many times over.

John, you didn't have to clear that up on my account because when I read something I usually understand what I read and I sure as hell wouldn't be mis-quoting you here or anywhere else as I deem that disrespectful at the least.

RD,

Yeah, I know you--and know you comprehend what you read!

I posted it because the thread had turned into a real hairball.

MD and others - when do you decide to test? Give it a dunking before it ever sees a set of scope rings, only after you see moisture issues or what?

For me, when they are new or before they ever see scope mounts.

RD, water boils at 212 degrees, not 140.
Thanks John for carifying this. A good practical test that I find useful. E

Did you think for a minute I was lying ? You could have saved yourself the embarrassment but I guess you're used to that by now.

I've seen you "misunderstand" such things before.
OK, he said he never said 140 degree water for 5 mins. Must have picked that idea up from somebody else.
The bottom line is that this is a very practical test that the owner of a new scope should perform before mounting the scope.
The other point(s) made here also tend to confirm the idea that using filler gases that have larger molecules may well be a good idea. E

Yes, E I'm sure I have not understood things on many different topics. On this particular topic I was sure he didn't but gave you the benefit of the doubt and asked him. In fairness to you, I don't hunt in hot climates like you do so maybe going above and beyond makes sense for your conditions. For me, it is totally unnecessary and I believe that the test you are performing puts undue stress on a scope. That's just my opinion.

I think that using filler gases with larger molecules as an improvement is a good thing and I applaud Leupold for doing the R&D. Sorry I jumped on your back like that. I'll try to behave in the future.

No problem. Like I said, when I sent the scope in that leaked, I described how I found the leak in the seals. Was repaired w/o comment.
So, 100 degree water for over 10 secs is enough.
Mine took five minutes to finally leak in two places. When repaired, it passed the same test just fine. As did my 4X and other 6X42 Leupolds.
Ok, so I over do it sometimes. I tend to hunt really tough conditions for extended periods of time. Have seen stuff belonging to others break down as well as my own. So I tend to be pushy/fussy when it comes to testing. E

Well, you know if you bought an Elite you'd be ready for anything................

teal,

To be honest, I don't do the dunk test much anymore.

When I started doing it, around 20 years ago, a lot of scope had problems. Cheap scopes often leaked, and some of the really expensive European scopes didn't have O-rings in their adjustment turrets, so bubbled immediately.

These days all the scope manufacturers (or, rather, the companies that make scopes for dozens of manufacturers) that I know of seal their scopes, and its pretty rare to see one with a leak. Mostly I tend to test used scopes, or brands I've never tested before.

MD - thanks. I've never done the test, was wondering what the "tipping point" was for some to do one.

What's next? Dip your barrel to make sure the muzzle tape is not leaking?

Question: How many have bought a new scope from Leupold that has fogged up in lets say 10years of use? I have a couple that old, but only one is presently on a rifle. It has not fogged.

Addition: Never mind, I just saw J.Bs. post. I seriously doubted that it was worth the effort with the progress that has been made with scopes.

I dont think I am gonna buy a scope and put it in 100 degree water just to see if it fails. E amazes me!

You could also pitch it out the window from the second story. Wait, Sticks Son pitched one off a tree and bench, with some heat IIRC and it still worked. Think I'll just mount them and then go shoot.

Seems like the ocular cannot be sealed as it's threaded to adjust focus.

Am I missing something?

Yep