When Should I Not Use WD-40?

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When Should I Not Use WD-40?
WD-40 was first used by the military in the '50s to clean up Atlas missile parts. Today, it's used by people everywhere to clean up virtually everything in need of a gleam. But don't go spraying the stuff just anywhere. WD-40 can cause more harm than good to certain household items. The DIY enthusiasts at Stack Exchange chime in.
Photo by Jorge Barrios.
Question: It seems like WD-40 can be used to lubricate just about any moving metal part. But is this true? Are there instances when WD-40 can be harmful?

WD-40 isn't actually a true lubricant. WD stands for "water displacing" and its main use is as a solvent or rust dissolver.

The lubricant-like properties of WD-40 come not from the substance itself, but from dissolving components. And the effect doesn't last.

WD-40 can be a good substance to start with — it can help clean up rust or other grime. But depending on what you're working with, you should probably follow up WD-40 with use of a true lubricant such as one based on silicone, grease, Teflon, or graphite.

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Firearms - You should never use WD-40 to clean or maintain firearms. WD-40 ishygroscopic and will attract moisture to the firearm which will result in rust.

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Drive chains of any type - Because WD-40 isn't a lubricant, it really will not work well on drive chains of any type.

Full Article: Lifehacker-when-should-i-not-use-wd+40