Wikipedia article on the subject was a little too technical, getting into layered molecular structure and non-lamellar structures and such. Hoping this sub can make sense of it.
In: Engineering
The blanket statement “they work better” is misleading and doesn’t help understand the differences in this case.
Lubrication can be thought of as doing two different functions, the first is reducing friction, the second is protecting from rusting.
If I rub two things back and forth with a dry lube, an oil, or a grease, they’re going to behave and accomplish those goals differently and in different proportions.
Graphite penetrates the surface “pores” of your materials and helps even them out so there’s less ‘grit’ to grab and then it just stays there until it’s wiped out of those pores. Oils and greases do something similar, but also film over the whole surface so even less contact occurs, and prevent oxidation.
Different tools for different jobs. They wear off/escape differently, attract dirt and grime differently and are significantly different to clean off when it’s time.
It’s actually an ongoing drama in the gun world over oil vs grease, or if letting carbon accumulate on certain bearing surfaces is ok, since the carbon fouling left over from gunfire is extremely similar to graphite dust.
(Grease at the way imo.)
Two sheets of graphite have very little holding them together, and because of how the atoms are oriented, little friction occurs between them once they get moving. So imagine having two very smooth surfaces sliding over each other.
Powdered graphite is essentially sand made of graphite. You wouldn’t use sand as a lubricant, so what gives?
Sand is made of silicon in a very stable crystal configuration. Graphite is carbon in a layered, unstable configuration. Putting diamond powder into a mechanism would be worse than sand, so it’s not the carbon.
Graphite is softer than almost any metal, Even paper can abrade it, that’s how pencils work. Graphite powder works by forcing graphite into all the little cracks and flaws in the metal surface. The graphite is so soft that it wears until the surfaces match exactly, and can slide freely.
Adding to others on why graphite works, because it is dry, it it suitable for applications where you don’t want an oily product carrier to get gummed up. Locks can use dry graphite or in a spray or liquid carrier that evaporates. Same with gun mechanisms.
Put a dab of oil on a glass surface and a dab of graphite also, cover them with lint from the dryer screen, now blow the lint off the glass.
Oily substances attract dirt.
The simple answer is that they each only out perform the other in certain types of situations/environments.
liquid lubes out perform dry like this: Liquids can be pumped and cooled/recirculated, used a bath/spray/jet and filtered and reused
dry lube locks, dry lube doesn’t attract dirt that gums up the mechanism..
some situations liquid lubes “fling off” and dry lube stays attached (graphite bonds and doesn’t fling off )
dry/solid lubricants are often better in hot and oxidizing environments that break down liquid lubes.
graphite needs humidity , so other specialized lubricants are used in a vacuum/space.
hope that breaks it down..
can you add a link the wiki article in question please?
Interesting, I’d been using a liquid (well gel like) product to lubricate the contact point for the string at the nut of my guitar, I guess pencil might work better, time to give it a go!
Latest Answers