Best scope antifog?

[Buck Buster]

I did have two! Leupold 3 to 9 power scopes that fogged on the inside, had one fixed and sold it, the other did clear up in time and I traded it for a 4 to 16 Tasco range finder scope. That was about 30 years ago , it has never fogged and is very clear. The range finder method works pretty good to, the last day of deer season one year I killed a buck with it at about 557 yards the scope said 600 I set it for that and hit him 2 out of 2 shots. Ranged the spot later with a Bushnell range finder and got 557 yards. I was using a 30-06 with 190 gr. sierra match king hollow point bullets, I recovered one that traveled from behind the left shoulder to just under the hide on the right hind quarter. It never opened up, just bent a little you could see the rifling marks the length of the bullet. Good luck hunting and be safe.

 

[hydehunter]

Best scope anti-fog I recommend is not shoving your face up into it, and not breathing into it (controlled breathing).

I knew you were making a joke I just did not have a good come back-Hydehunter

 

[Barrelnut]

Ok, seems to be some confusion here about what causes a rifle scope to fog up on the external lens.

The rifle scope fogs because it is cold and your exhaled breath is very warm and contains lots of moisture. When the warm exhaled air hits the cold lens surface, the moisture in it condenses.

Water condenses and sticks to the surface of the lens because the lens is colder than the warm air it is exposed to. Cold air cannot support as much water as warm air, so the moisture in the warm air, just at the surface of the cold lens, starts to condense and sticks to the lens in the form of very small water droplets. This is known a the "dew point". It's the temp where water starts to condense in the air. The condensed water on the lens consist of millions of small water droplets. The droplets refract and disperse light so that you cannot see thru the lens.

Anti-fog treatments that you spray, wipe, or rub onto the surface of the lens DO work. They work by one of two ways.
1: The treatment lowers the surface tension of the water so it cannot bead and therefore refract light. detergents work this way. This is why a very small amount of dish soap rubbed on the lens is a good anti-fog treatment.
2: The treatment itself attracts and disperses the water so no beads can form. Glycerin and alcohol work this way.

Now, coatings like Bushnell adds to the lens work too. They are more durable coatings of some sort but probably still work by inhibiting the ability of water to bead on the surface of the lens. Hey, maybe they use RainX!

So, oddly enough, road hunting does not cause fogged rifle scopes. Because the scope is kept warm inside the truck and is not cold enough to cause condensation when warm exhaled air hits it.

 

[sp6x6]

I ski raced for years we used some tye of anti fog inside of goggles.Many types made that work

 

[Rich Coyle]

Barrelnut,

Maybe you can tell us why two scopes fogged when I took them from the pickup at the range on a cold day. Neither were breathed on.

 

[Barrelnut]

Don't know, but the scopes had to be colder than the air they were in for it to happen. That's the only way things get condensation on them.

Think of your ice cold beer out by the pool in the summertime. It gets that nice cool wet frosty condensation on it. That's because the beer can is a lot colder than the surrounding air. Now think about that nice steaming hot cup of coffee you have every morning, ever seen condensation on it?

Oh, forgot, you live in Oregon. Heck when it's cold and the humidity is 95%, just barely not saturation, which is called rain, almost anything can get condensation on it, it's called dew.

 

[Buck Buster]

Very good example Nut.

 

[MudRunner2005]

Don't know, but the scopes had to be colder than the air they were in for it to happen. That's the only way things get condensation on them.

Think of your ice cold beer out by the pool in the summertime. It gets that nice cool wet frosty condensation on it. That's because the beer can is a lot colder than the surrounding air. Now think about that nice steaming hot cup of coffee you have every morning, ever seen condensation on it?

Oh, forgot, you live in Oregon. Heck when it's cold and the humidity is 95%, just barely not saturation, which is called rain, almost anything can get condensation on it, it's called dew.

Good example, but I think what you mean is that anytime you have a large instantaneous temp-swing going either way, you're going to get condensation...And not in just one direction.

I've pulled warm scopes out of hot trucks with the heater on, into 10-20 degree weather, and they also fog up instantly, while it's temporary, they still fog up when they hit the cold atmosphere. Sort of like when you're wearing sunglasses on your head while inside your house (wintertime), then you walk outside and get in your cold vehicle and put your sunglasses on your face, your sunglasses fog up.

 

[Rich Coyle]

Don't know, but the scopes had to be colder than the air they were in for it to happen. That's the only way things get condensation on them.

Sorry, but the scopes were quite warm. They were laying on the front seat. They were way warmer than the air at the range. I took three scopes that day. The Bushnell didn't fog. The other two did.

 

[Barrelnut]

Rich, sorry I cannot explain how the scopes fogged in your situation. Maybe if you spend a little time exploring the science of condensation, you will discover why the scopes fogged and share your discoveries. I would like to know for I am at a loss as to explain it.

Condensation is well understood and documented basic science. Below is a basic definition, with examples, of condensation from a science organization website.

Condensation is the process by which water changes its state from a vapor or gas to a liquid. Condensation is responsible for the formation of clouds. Common examples of condensation are: dew forming on grass in the early morning, eye glasses fogging up when you enter a warm building on a cold winter day, or water drops forming on a glass holding a cold drink on a hot summer day.

Condensation occurs when water droplets form due to cooling air. When warm air cools, water leaves the vapor that is in the warm water and condenses into liquid.

Cheers.

 

[Barrelnut]

Silence? Yea, figured as much. I usually find, that if ya can't explain it, it never really happened. LOL

 

[Rich Coyle]

Did you think I was interested enough to check about condensation? And then write about it? I couldn't care less about why two scopes fogged and the Bushnell didn't. I solved the problem by selling them. Now I have three Bushnell 6500 4 1/2-30X50 and one 4200 4-16X40. They don't fog.

 

[Barrelnut]

You were sure interested enough to keep asking the question, when it suited you. But when asked to substantiate your claims, you loose interest?

Your claims were actually BS and, I'm pretty sure you know it.

 

[Rich Coyle]

Okay.