Rifle Scopes How To Gas Purge a Scope?

[Strykervet]

I have this Elcan C79 scope that can't be sent back to Canada due to "Patriot" act. So if I'm to change the tritium, I have to do it myself. I spoke to someone about it at Raytheon up there years ago, but now whoever I call is a dick and won't talk to me. He mentioned using a tank of nitrogen and a thin wand and changing the part out and using the wand to blow nitrogen inside the scope, then seal it up. The lamp is just glued to a little holder that rests under a screw in the bottom of the optic.

How do they normally do it? I doubt they do it with robots or gloves in a sealed environment, but I could be wrong. If that's the case, I figured I could make one out of a Rubbermaid container. But if I don't have to, if I can get away with just blowing the gas into the scope, I'd rather go that route.

What say you all? And again, sending it in is out of the question and there's really nobody to call direct regarding 'em. I have the manuals but not one that goes into detail about that. Thanks.

 

[Mr. Z]

I’m meeting with the warranty repair guy from vortex tonight, I’ll ask what their process is for you.

 

[SubOptimal]

More than likely done in a glove box, not Tupperware. This way they can create an inert atmosphere within the box to start with.
A word about N2, there are various grades of the stuff. Ideally, you would want UHP (Ultra high purity) but, that stuff is expensive, at minimum the grade you would be looking for would be DRY. Argon would work as well it tends to be dry as shipped but it is more expensive due to the process needed to make it. Do a pretty long purge before sealing the scope, the idea is to get the H2O vapor out of the scope and that takes awhile. It is a little different from the purge used in tube welding but the same idea.

 

[Pvt.Donut]

Depending on the gas, you just fill a container with it then let the scope sit in it for awhile then seal up the optic.

 

[SubOptimal]

Depending on the gas, you just fill a container with it then let the scope sit in it for awhile then seal up the optic.

Which is why you will never work for an optics company.
The gas has to move through the scope tube and into all the nooks and crannies around in there. Even the glove box needs to be purged and the interior air replaced on a regular basis.
A stationary dump into a fish tank or bucket will do next to nothing.

 

[918v]

Have you tried Eurooptic? They are great at getting foreign mil stuff fixed.

 

[flyer]

Yeah, I would probably do a little vacuum bake out to remove moisture and then add inert gas. The vacuum chamber would probably be the interlock for the glove box and it would probably have clean room style washing and cleanliness protocols to avoid getting dust and other foreign material inside a scope.

On a budget you could put together a facility like that for $3-4,000, more if you wanted plasma cleaning and other nice stuff.

 

[tadawson]

The degree of purge would be related somewhat to if it lost seal in the first place, or if you simply opened it to make this change, and had some degree of control of the environment that was done in. If only open for moments in a controlled space, then the need to bake/etc. to remove moisture just isn't there . . . If the seal failed some time ago, then yes . . . In any case, not something to be done in the kitchen, but definitely not impossible either . . .

 

[awp762]

tag for later

 

[Steel+Killer]

if I can get away with just blowing the gas into the scope, I'd rather go that route.

That way would work as about as well as a "no pissing section in a swimming pool"

 

[ncr92]

I think the idea is to put the scope in a pressure vessel, apply a vacuum to it and then fill the vessel with pure nitrogen. You repeat this process a number of times and it purges virtually all of the moisture carrying air from the optic.

Here's a guy who made his own:
https://m14forum.com/optics/145718-my-scope-purging-system-super-thx-bambam.html

I think it would be cheaper and easier to do your repair and then have someone with a nitrogen purging system do this for you. Anyone who does repairs on sealed optics would need this facility.

 

[whatsupdoc]

^ that should work, You could use a AC gauge set and a vacuum pump, pump down the pvc chamber to boil off any water then fill it with nitrogen.

 

[Yellowhammer]

What about some of the night vision repair folks? They do purges on nvgs and might have some ideas.

 

[Strykervet]

So I think I know what I need to do. Long story short, I need to make and seal a Rubbermaid box with glove holes and a dry nitrogen tank with all my shit in the box when it's sealed up. A balloon to displace air in the box, another on the box to indicate pressure and the outlet connected to a vacuum pump. I plan on vacuuming the air while balloon is full of nitrogen, then fill with nitrogen, vacuum, repeat 3x total. Then empty balloon and fill box under pressure with nitrogen to around 4lbs. Remove screw holding tritium lamp, remove lamp, clean old on out and install new one in holder, then reinstall when dry. Reinflate balloon some, then using hose blow out inside of scope with nitrogen, vacuum, refill, repeat several times using hose to blow nitrogen into optic. Finally repressurize to around 4lbs. or so and install new lamp with screw, sealing screw with Teflon tape or some type of water resistant non-fuming anaerobic sealant that can be removed without heat in the future.

This is something along the lines of what I discussed with Raytheon engineer years ago. Burris video kinda confirmed it. So, has anyone ever done this, anyone ever purge a scope on their own? In this case, there aren't too many options, if any really, that can be taken besides DIY. And it doesn't seem like a hard job at all, just being certain it's purged properly.

I do have on my side that I'm only changing the lamp and that it'll be disassembled inside the nitrogen environment. So it's already purged and water free, I really just have to keep it that way while I do the job.

Any better ideas?

PS, even if Trijicon worked on these, which they don't, it's $400 to replace tritium in a scope I think, one of theirs, and I maybe paid $400 for it when I got it. So I'm not looking to spend a lot on it, just enough to do it right. If anyone is in WA and wants to replace tritium or install an LED in a scope, we could all pitch in together and split the costs and the more people that do it, the less it costs us all. PM if interested in doing this.

 

[GeoffatBurris]

How hard could it be?