Nitrogen Purging a scope.

[Grimstod]

I have done this a few times now with telescopes that I use for astronomy. You take out the lens sells and blacken the edges of the lenses. This increases contrast by a noticeable margin.
No I just acquired an SWFA 5-20x50 and I also have a Leupold 40x Benchrest scope. Both do not have blackened lens edges. I am contemplating taking them apart and blackening the edges since it would increase contrast and probably make bullet hole siting easier. Think is this wold ruin nitrogen purge. Is it easy to re nitrogen purge a scope. I would think that most scopes would eventually leak anyway.
Here is a video example of blacking lens edges.

 

[fkimble@charter.net]

Since it does not have a valve on it like AC units have to purge out the moisture and put freon back in, then close valve to keep it from coming back out, I would say it is going to be near impossible. Sounds like a good way to ruin a good scope. So a little better contrast or fog. Which to you prefer?

Frank

 

[WSnyder]

Scopes are generally purged not pressurized. Common misconception. You are correct that over time the nitrogen could disburse or be contaminated with atmosphere “air” over time. O-rings are not leak proof or impermeable.

 

[mikecr]

I would think purging before final assembly (in a glove box) would be appropriate..
The learning of how to disassemble/reassemble could be difficult.

 

[CJ6]

Doesn't Leupold use Argon now ?

 

[freebird22/250]

I would think if you disassemble your Leupold scope it would void the factory warranty, i would check with them first.

 

[WSnyder]

Doesn't Leupold use Argon now ?

Many use argon now. I believe argon molecules are larger than nitrogen so in theory it will “leak” slower. Supposedly argon’s properties allow it to do better in the cold than nitrogen.

 

[Grimstod]

Since it does not have a valve on it like AC units have to purge out the moisture and put freon back in, then close valve to keep it from coming back out, I would say it is going to be near impossible. Sounds like a good way to ruin a good scope. So a little better contrast or fog. Which to you prefer?

Frank

Considering the shelf life of such purging is this even going to be a factor. My scope is over 20 years old. I cannot see any scope holding on to that nitrogen that long.

 

[Grimstod]

This actually looks pretty easy.

 

[c3d4b2]

There is a book by Dr. J. W. Seyfried "Guide to Riflescope Repair" that has information on rifle scope purging. Some scopes have a port in the at the beginning eye piece threads. The book also shows injecting nitrogen through the windage assembly.

The book copyright is 1985