Rifle Scopes Optic cleaning

Lance B

Sergeant
Full Member
Minuteman
Mar 13, 2008
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NJ
I saw the video of how to clean a scope by US Optics. They use compressed air and acetone. Recently I saw a shooter use compressed air on his S&B scope and it destroyed his scope. How would acetone not damage the coating on the lens? How do the hide members clean their rifle scopes?

Lance
 
Re: Optic cleaning

Can of air to blow debris out, q tips with acetone around the edges. and then a lens cloth with light acetone on the lens. USO and Premier recomend aceton so I go with that, they know more about the coating than anyone
 
Re: Optic cleaning

I saw it at the hide cup. A shooter dusted off his S&B scope lens and it took off the coating. The can sprayed the lens with the freon from within the can.
 
Re: Optic cleaning

Here's a tip, when using compressed air in the little cans that you can buy, don't hold the can UPSIDE DOWN when spraying the "air" cause all you're spraying is the propellent in liquid form which comes out at probably -100 F.

When he hit his objective lens with the liquid, glass doesn't react well when it's about 100 F and gets hit with -100F. Can you say Shattered objective lens!!

I'll be they get a laugh at that when they get the scope in for repairs in Germany.
 
Re: Optic cleaning

Treat it like a high quality camera lens since that's the level of optics you're dealing with.

I have a light haired lens brush, qtips for the edges that I use to push a piece of lens cloth around, and a lens cloth.

Never wipe in a circular motion, if you have a minute piece of grit on there you just etched a halo into your objective.

Acetone is an iffy prospect that I avoid. Sometimes I use a faintly alcohol damped lens cloth. The problem with liquid solvents is that it's possible to seep it through the seals in a camera lens. I don't know if this holds true for a rifle scope, but I'm not about to push it and find out.

If you seep a solvent around a seal (remember most solvents like acetone have a very low viscosity compared to water, which is what the seals are there to protect against) you can quite easily pull oils and lubricants from the moving components and coat the inside of your optics with something that doesn't wipe off.

I saw this happen a couple times to a 300mm Canon lens, needless to say the owner was furious.
 
Re: Optic cleaning

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tburkes</div><div class="ubbcode-body">When he hit his objective lens with the liquid, glass doesn't react well when it's about 100 F and gets hit with -100F. Can you say Shattered objective lens!!</div></div>

Ah... I get it now... yikes. Guess the can-o-air tells you to keep the can 6"-8" away for a reason!
 
Re: Optic cleaning

In the field, I am more likely to have a lens brush and cloth in my pack than a can-o-air. But, because of the different type coatings used by various optics manufacturers, I would follow the cleaning instructions for their particular scope.
 
Re: Optic cleaning

I haven't studied up on scope optical properties, but if they're anything like camera lenses, the ocular portion of far more vital to keep scratch/dust free than the objective.
I would refrain from cleaning as long as possible if you don't see any degradation of optical quality. Cleaning done wrong is far worse than no cleaning at all.
If you do want to clean up your lens I recommend you use a bulb air blower (the ones you squeeze with your hand, kind of like the booger suckers for babies). Use this to get any visible debris off the lens - wiping any grit on the lens will scratch it most likely.
Once visible debris is gone, use a safe cleaning solution (I use Eclipse sensor/lens cleaning solution, I think there is even a version for specially coated optics, and either a lens cloth or pec pads). Don't rub too hard.