View Full Version : Vintage K4 scope overhaul
March 18, 2012, 10:00 PM
I've just purchased a Weaver K4 steel scope. It looks like maybe it isn't sealed as well as it once was......I'm considering taking it apart to clean and reseal it. I have Argon/CO2 blend for my MIG welder....... Has anyone here done this themselves and had good results? Thanks y'all for any helpful advice. Pathfinder
March 20, 2012, 09:44 AM
Nope - I only do my own dentistry & brain surgery. :rolleyes:
March 20, 2012, 10:00 AM
Has anyone here done this themselves and had good results? Thanks y'all for any helpful advice.
Don't know about great results but after I did, got good performance. This has been a few years since I did this. I used Nitrogen as the fill. I Only cleaned the outboard lenses and Sealed the threads, on the bells with a high grade of silicon grease. When I filled, I help the scope vertically, filled from the bottom, inserted the fill tube as far into the scope as it would safely allow me to do. Give it a few seconds for the Nitrogen to displace the ambient air inside. Then re-install the last bell. ... :)
Have no working knowledge of Argon/CO2 but Nitrogen is lighter than air and once you have the pressure inside, it will displace the air. You really don't need much, just inches of water column. .... ;)
Good luck; Said Marco from Tropoya .... ;)
Be Safe !!!
March 21, 2012, 07:43 AM
As air is 80% nitrogen, it's neither lighter nor heavier than air. Argon/CO2 is heavier than air, so you can fill the glass like a bottle holding the opening up. Don't under estimate the exchange-time, as you're not really trying to get the oxygen out but really want to get all water vapor out.
March 26, 2012, 07:27 AM
you only want to displace the air. The heavier than air gases will work as long as they don't "absorb" moisture, or have a color. The lenses in old scopes sweat and fog for the same reasons an old window or glass soda bottle does. Once you get everything clean and filled, your next deal is to seal it so it won't leak, with whatever works, o rings grease, etc. I have an old brass weaver on an old Savage 24 I need to do the same thing to, as soon as I find some gas to use.
March 28, 2012, 07:40 PM
Are you near Seattle?
Come over to my house and I will give you a broken down old K4 that you can dissect.
March 28, 2012, 08:23 PM
If you want the scope rebuilt if things do not go as you want www.ironsightinc.com will service it for you. A rebuild is about $85.
March 28, 2012, 09:39 PM
There is a NYFD guy in Yonkers who does them very reasonable $$. I used him.
March 29, 2012, 02:26 AM
Ironsight did a USA 4x REdfield for me 10 years or so ago, $55 bucks as I recall. Well worth it. I had to call them back up on a minor issue, and they were easy to talk with and very helpful to boot. Good outfit in my book.
March 29, 2012, 08:12 AM
I work on optics for a living so here's my advice.
IF (big if) you decide to do this yourself get the right tools NOW before you get stuck with the thing partly dismantled.
White cotton (not nylon) disposable gloves.
Adjustable pin wrench.
Lens cleaning tissues & a good cleaning/anti-fogging solution. (See if you can find some "ROR" Residual Oil Remover, it is much better than the soapy water sold at camera stores.)
Flat Black, or Dead Black (a specific type of dead fast drying paint.) it is used to kill internal reflections & replace missing paint & cover screw heads internally.
Clear nail polish, used as a lightweight Loctite.
Dust free area to work in. & I mean dust FREE. tiny specs you can't see will become boulders after re-assembly.
Drawing equipment. at least an 8 1/2X11 notepad, rulers pencils & so on.
Draw every single component as you remove it, not its exact position & alignment. Use the drawing to correctly re assemble when you're done. Note things like the exact number of threads unscrewed internally this will allow you to re assemble without a collimator or optical bench.
Get, or make a tray with lots of internal dividers, as you tear down the scope put the components in order as they come out, work left>right, or right< left it doesn't matter which but you must be consistent.
The gas purge can be easy, but you need to use the right stuff & understand why. There is no need for pressure, it'll just blow put anyway. The gas must be 100% bone dry, most welding gasses aren't that dry. Nitrogen is used to prevent fungal growth internally, plus there is a law of physics called "Partial Pressures" what nitrogen does is extinguish life (fungus etc.) while being 4/5ths of the surrounding air. If you use something that is only 1/100th% of surrounding air it will diffuse much faster. To do a nitrogen purge all you do is open the scope, put it in a sealed environment (Mylar bag held open with coat hangers is fine), fill with nitrogen, wait, squeeze bag til as empty as possible, refill with nitrogen again. 3 cycles will purge everything except nitrogen, then just re-seal the system inside the bag.
Good luck with the project.
March 31, 2012, 09:58 AM
Wow posts #2 thru 5. Advice that goes 180 degrees and twice I believe..
Not all are correct.
April 3, 2012, 10:34 AM
I work on optics for a living so here's my advice. ..
White cotton (not nylon) disposable gloves...
I am sure you know more than me about this, but I did work around some optics engineers. They sometimes wore purple gloves.
When they would haul me into a light room with the metal bench with threaded holes and turn down the lights to show me flicker at the bottom end of night vision and then... I got sleepy. The purple glove men are ushers to the world's most boring movie.
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