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Old January 8th 18, 06:25 PM posted to rec.aviation.soaring
jfitch
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Default Lubricant for spar pins

On Monday, January 8, 2018 at 4:42:18 AM UTC-8, wrote:
Hi Eric
I see the Aeroshell 5% molybdenum disulphide grease is now sold as Aeroshell 64. It's widely used in aircraft. I wasn't aware of the Schleicher caution against it, and haven't seen any caution from SH. I wonder where Schleicher got their information. I don't see any problems reported when using it with brass in an internet search. There is a copper-corrosion test in the 21164 mil standard for greases (5% moly grease passes) but the real-world meaning of that test isn't clear to me.
regards



My ASH 26 E manual warns against using molybdenum disulphide grease (Aeroshell 33
contains 5% of it) on the main pins because it can damage the brass bushings in
the wing. So, be sure to check it's compatibility if your bushings are brass.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf


Dry moly can cause corrosion, as it absorbs moisture from the air and the disulphide turns into sulfuric acid. Any good grease is a concoction of ingredients, some of which are inhibitors to make sure that doesn't happen. I believe the concern is theoretical, more than real.