* Photo: Tim Morris * The recipe for this superlube has long been a closely guarded trade secret—until now. Wired sent a can to the lab and got the ingredients.
Mineral Oil
Seriously. WD-40 is mostly a mix of baby oil, Vaseline, and the goop inside homemade lava lamps.
Decane
WD-40 contains an abundance of alkanes—hydrocarbons that match the formula CxH2x+2, usually in a long, zigzagging chain. This one, C10H22, which is also a common ingredient of gasoline, helps WD-40 remain a liquid at cold temperatures. Decane doesn't freeze until around -21 degrees Fahrenheit.
Nonane
Another alkane. One reason these molecules are so handy here: Their hydrogen atoms don't hold a charge, so they can't connect to the hydrogen or oxygen in water, which makes alkanes water-repellent. WD-40, after all, stands for "water displacement, 40th attempt."
Our lab analyzed WD-40 with gas chromatography (GC) and mass spectroscopy (MS). GC separates chemicals based on size, boiling point, and other factors, releasing them one by one over time. MS then blasts the molecules with an electron beam and tells what's what by the mass of the ionized fragments. Tridecane and Undecane
Freeze-resistant? Check. Water- repellent? Check. Contains an alkane that is the major product of the red-banded stinkbug's scent gland? Check! Many alkanes are naturally produced by living creatures. Undecane, part of the pheromone trail left by cockroaches and ants, is present.
Tetradecane
Another alkane! Zzzzzz.
Dimethyl Naphthalene
Here's the thing: This stuff (C12H12) comes in 10 forms, called isomers. One of them is a harmless hormone given off by potatoes. Another is used in high-performance engineering plastics. Our analysis can't determine which ones are present here, but if you're using it as a solvent, as is likely the case with WD-40, they all work just fine.
Cyclohexane
That cyclo prefix means that unlike standard alkanes, which come in chains, this one's a ring. The shape gives cycloalkanes a higher melting point. And huffing them will knock you out cold. (Or so we're told.)
Carbon Dioxide
The WD-40 company claims that by using this gas as a propellant, it avoids using smaller gaseous alkanes (possibly butane and propane), which can be hazardous to the environment. As if CO2 isn't.
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