The History of WD-40

Edit: And it's not "going all religious", it's because I do 6,000km on my bike every year. I know through my own mistakes that WD-40 is not a good chain lube.

It absolutely is bad. It's mineral oil with a few random additives thrown in. https://www.wired.com/2009/04/st-whatsinside-6/

Popular Mechanics tested WD-40 in five popular uses and found it to be the worst choice in every case. https://www.popularmechanics.com/cars/how-to/a6064/wd-40-vs-...

> Wrt lubricating properties: there's numerous threads of cyclists going all religious over this.

The cycling community overwhelmingly has been telling generations of newbie cyclists to stop hosing down their chains with wd40 and use a proper oil. There are a few people who swear by it, but they're people who have never tried anything else, or not actually looked at their chain wear.

> Because of the penetrating/cleaning/anti-rust properties combined it has the tendency to give a super clean chain with not a lot of dirt in it

WD-40 does not have any special penetrating abilities. Further, the gaps in a bike chain between the various parts are not so small that one needs a penetrating lubricant.

What is important is wear, not how clean the chain looks. Wear happens on the pins, inside rollers, and the holes on the chain plates. The chain lengthening means wear on the sprockets, which are significantly more expensive than the chain. A 10-speed chain is maybe $50 at most for a pretty nice one, and chainrings plus cassette can be significantly more than that.

The proper chain lube to use depends on the intended conditions, but any lubricant needs to have sufficient film strength - ie keep metal from directly contacting metal.

WD-40 has virtually zero film strength. There are a thousand lubricants out there that are better.

> (unlike any other pure lubricant since those just attract and accumulate dirt).

I'm not sure what "pure lubricant" means, but there are plenty of dry lubricants suitable for chain use. They are designed for dry conditions, especially dusty ones.

Riding in wet conditions usually means you're using a fairly thick chain lubricant.

Periodically measure the chain with a ruler to check for chain stretch and replace before wear gets too high that it starts destroying your cogs.

Editing to add:

If you want to use a wet lubricant for chains, bar and chain oil (ie chainsaw oil) will work just fine.

If you want a dry lubricant for chains, use something like Finish Line PTFE. Dupont themselves also sell a PTFE spray, as do several other companies.

If you want a crazy penetrating lubricant, McLube's Sailkoat is pretty crazy stuff, but a large spray can is $20+.

If you want rust prevention/protection, LPS-3.

If you need a penetrant or rust breaker for bolts, you can try the following: Mouse Milk ($$$), Kroil. Mouse Milk is weird stuff, I believe mostly d-limolene (so don't use it near waterways!) but apparently popular for lubricating very high temperature stuff (turbo wastegates, for example) because it does not leave ash/residue behind.

This is basically the theory behind Rock'n'Roll's lubes [1] (and perhaps other dry lubes, i don't know):

> Rock'N'Roll chain lubes are formulated to clean and lube at the same time when applied. EXTREME, ABSOLUTE DRY and GOLD go deep down into the links, trapping dirt and floating it to the surface where you can wipe it off. Rock'N'Roll chain lubes create a protective membrane that keeps new dirt out and the lube inside, where it's needed.

So you douse the chain with it, run it round to work it in, then wipe off as much as you can - the stuff you wipe off carries away loads of filth, and the bit that stays behind dries to leave a wax/teflon layer on the working surfaces of the links. Or something. Whatever it does, it seems to work pretty well!

[1] https://rocklube.eu/en/12-chain-lubes

Especially the second thing depends I guess on capillary properties, which other lubricants (e.g. silicon oil) don't necessarily have?

I used to use it as a carburettor aide for rarely used lawnmowers to kick start them into life but this is probably bad for the engine. There are real products for this.

Penetrative oil for mildly rusted on screws and bolts.

And.. a really bad chain lube, or hinge de-squeeler. Basically these things deserve proper lube molybdenum/disulphide stuff. You're depending on the graphite (I think) in wd40 to do the job before the solvent strips all the real lube out.

I've also used it on bike chains, to clean off a lot of the old nasty before reapplication of a purpose-created lube.

In general if you need to lubricate anything important, you should look into what the official documents recommend. The right lubricant varies a lot depending on the application. Some stuff uses thin oils. Some uses sticky oils. Some wants grease. The right thing to use depends on things like manufacturing tolerances, the presence of oiling systems and the operating environment, so best to just check the manual.

I use it to winterize my motorcycle in winter months giving the metal parts a thin film of WD-40 (being careful to avoid the brake calipers and rotor).

One might suggest:

A) Reading what it says on the tin can what it is for

B) Consulting its Wikipedia page, which states in the first sentence that it is a https://en.wikipedia.org/wiki/Penetrating_oil, and that article further explains what those are good at, and what not.

Silicone will make plastic on the outside of your car appear like new again but the effect is short-lived, like two weeks, and there'll be a period after that where it looks blotchy. Door rubbers are OK with silicone but I've used vaseline to similar effect.

It was everywhere after my MIL wiped the whole house down. That spray was strictly not approved for indoor use, and it did not go away ever. My mother finally found a cleaning product that seemed to help, but this was a huge PITA for months and we were so mad. We thought about redoing all wooden floors for ~7k € (in a rented place after all).

I was also angry at me, because I know that several larger production facilities have strictly banned silicone based products from their premises, because it will contaminate everything it touches (and everything that thing touches) for the further production steps, e.g. painting. You will never ever get that product off these surfaces again, and it will continue to contaminate until you throw everything in the bin.

All the professionals we talked to were convinced that they know no way to get rid of silicone on surfaces (especially indoors in living quarters with small kids present), and sanding the floor down would probably just spread it - cross-contaminating the surfaces again.

There are uses for silicone spray (bicycle maintenance, outdoors, cars, etc.), and I would have one at home for these cases - but that whole product line is strictly forbidden at our home forever.

WD-40 doesn’t have a ‘pea’ [*], so I sometimes find myself shaking the can—because I shake all aerosol cans by habit—and find myself wondering if it’s necessary.

https://en.wikipedia.org/wiki/Aerosol_paint