Nitrogen vs Argon

[Raythemanroe]

I have read some scope manufactures are now using Argon in there scopes instead of Nitrogen. There stated reason is Argon is a bigger molecule or chemical make up and this translates to less chance of leakage or bleeding off of sorts..I wonder if Argon even with it's larger structure is as stable or strong as Nitrogen may be? Has anyone done any testing on the differences or seen any added benefit over the norm?

 

[CatShooter]

I have read some scope manufactures are now using Argon in there scopes instead of Nitrogen. There stated reason is Argon is a bigger molecule or chemical make up and this translates to less chance of leakage or bleeding off of sorts..I wonder if Argon even with it's larger structure is as stable or strong as Nitrogen may be? Has anyone done any testing on the differences or seen any added benefit over the norm?

It is advertising... neither gas leaks out of a good scope, and both will leak out of a bad scope or a damaged seal.

 

[dickn52]

My molecules are smaller than yours game?

 

[Keith Glasscock]

The only reason I can think of to "purge" a scope with Nitrogen or Argon is to remove water vapor thus preventing fogging.

There would also be the secondary effect of preventing corrosion - no Oxygen, no oxidation.

I doubt there is any difference between the two for scope use.

 

[AndyTaber]

Back in my days working in a Metallurgical lab, we used a Spectrograph to analyze iron chemistry. This was done by firing an electric arc in an Argon atmosphere. Argon was used because it is virtually colorless.

 

[Minesweeper3433]

Nitrogen is still good enough for military use in Nightvision and thermal sights.

 

[normmatzen]

I believe Argon is a bit more inert than Nitrogen.

 

[Area Man]

The only reason I can think of to "purge" a scope with Nitrogen or Argon is to remove water vapor thus preventing fogging.

The "air" inside an unopened package of potato chips is nitrogen.

My brother got the tires on his truck filled with nitrogen. Says it prevents slow leakage.

 

[Raythemanroe]

Tractor trailer steer tires run Nitrogen and Race cars because it doesn't build pressure as fast from the heat.

 

[mmcu]

Let's all go back to our basic high school chemistry class - Argon, a Noble Gas, has a slightly higher atomic weight than Nitrogen (~3X) - question answered as to size.

Both are perfectly suitable for purging scopes. Nitrogen is proven with Argon being newer on the scene.

 

[bubbalo7]

Well it really doesnt matter which inert gas the use.They are both used to remove all the oxygen in the scope.Both are heavier than air.And as long as the seal is not compromised the wont FOG or Leak water into them.Its just a marketing tactic I imagine.Just something different.

 

[mac86951]

Tractor trailer steer tires run Nitrogen and Race cars because it doesn't build pressure as fast from the heat.

Yup. Purge air and moisture out, larger molecule seals the schraeder valve better (less slow leak) and better thermal properties.

Argon would be thermal choice over N2, though either is better than a scope filled with air. Bigger decision will be the index of refraction of the two gasses aligning better with planned lense coatings.

 

[Dusty Stevens]

Im part of the tribe that thinks both are marketing gimmicks and neither works for whats advertised. The ocular bell threads wont hold gas and are not sealed. They may blow it thru there to eliminate moisture but i doubt any scope in the box leaving the factory has nitrogen or argon inside. Ive had too many apart and know how fast small nitrogen molecules leak. Nitrogen in tires doesnt heat up and expand building pressure is why its in tires. It actually leaks faster than 78% nitrogen which is what a plain ole compressor puts in. Lots less water vapor tho

 

[XTR]

I'd bet it has more to do with which is more readily available and cheaper from the local Airgas vendor. Than anything else. I've used both to purge piping systems in the past.

As for Nitrogen in Car tires... yea, sure, if you want to.... http://www.edmunds.com/car-care/should-you-fill-your-cars-tires-with-nitrogen.html

 

[biggen0_8]

I think if your scope has argon and your bullets have plastic tips that don't melt, you'll shoot smaller groups. HYYYYYPE

 

[joshb]

Does it help negate the coriolis affect at short range? Personally, I'd use helium. It would make my gun lighter.

 

[msinc]

Im part of the tribe that thinks both are marketing gimmicks and neither works for whats advertised. The ocular bell threads wont hold gas and are not sealed. They may blow it thru there to eliminate moisture but i doubt any scope in the box leaving the factory has nitrogen or argon inside. Ive had too many apart and know how fast small nitrogen molecules leak. Nitrogen in tires doesnt heat up and expand building pressure is why its in tires. It actually leaks faster than 78% nitrogen which is what a plain ole compressor puts in. Lots less water vapor tho

Me too, I can tell you that Unertl never used it in his scopes. Even the last of the Unertl's, the 10X USMC sniper. I know this because one of the peculiar things about this scope is that you can unscrew the entire rear tube and occular and look right at the reticle. Mine does not and has never fogged. I would think that a military grade sniper scope fogging up could/would not be tolerated by the Marine Corps.
That said, it would certainly make a good gimmick as the gases are odorless and tasteless and colorless...how could anyone ever prove that they were there in the first place.
Scopes that did in fact use it had a purge system that allowed the scope to be filled I guess when it was deemed necessary...the Leatherwood ART II is a good example.
In all fairness, argon is the heavier inert gas and it should be the least of all of them to leak, but that's not to say it still cannot or will not leak out.
It seems to me that a scope opened up in a very high humidity atmosphere and allowed to get the "wet" air inside would fog later in a dry climate with a different temperature. By the same token, if a scope was opened and extremely very dry zero humidity air was blown in then it was sealed there is nothing to make fog...until humidity leaks in again. I don't care what kind of gas you put in the tube that will not stop it from fogging on the outside.

 

[Markk9]

Tractor trailer steer tires run Nitrogen and Race cars because it doesn't build pressure as fast from the heat.

The reason they use nitrogen in race car tires, is that the pressure build is predictable, all gasses expand as they are heated. General air is not predictable mostly because of the moisture content of the air in the tire.

 

[skiutah02]

This is a guess, although an educated one. They are probably marketing this using the concept of effusion. Nitrogen molecule and argon atom have different radii and masses. A gas will pass through a small hole faster based upon less mass. N2 is cheap and has mass 28. Argon is rarer thus more expensive but has higher mass 40. IF the scope were sealed with either of these, argon would "leak" more slowly through small pores in any oring because it has higher mass. Argon is less chemically reactive, but N2 is effectively unreative. For a real world analogy, a helium balloon is "sealed" but has very small holes in the rubber. Helium will very slowly escape through these pores and the balloon will shrink. If you used Argon, the ballon would deflate much more slowly since it has nearly 10x the mass (but would not float since it is denser than air). This is why every kid is saddened that eventually their prized He balloon eventually sinks to the floor....this leaking is called effusion.

 

[Outrider27]

Does it help negate the coriolis affect at short range? Personally, I'd use helium. It would make my gun lighter.

That was a great laugh for me; during a long and varied engineering career I got to do some work with heliox mixtures used in diving systems for deeper depths, and in one application the helium/oxygen mixture was mixed on sight due to different % oxygen requirements of the blend for different depths. The helium side of the system was a real pain in the butt - that stuff has small molecules that will leak through/past anything eventually - I swear some days it seemed almost as if it would leak through the walls of monel or stainless pipe. At one point we were even developing acceptance standards for soft seated valves that were zero leakage valves when used with conventional diver's air. Nitrogen and argon may be heavier, but I prefer working with them any day, unless we're talking balloons.