The WD in WD-40 Stands for Water Displacer

That blue and yellow can sitting in your garage has a name that's basically a lab report. WD-40 stands for Water Displacement, 40th formula—because it took 39 failed attempts before chemists finally nailed it in 1953.

The Rocket Chemical Company in San Diego was trying to create rust-prevention solvents for the aerospace industry. Their team of three worked in a tiny lab, testing formula after formula. When number 40 finally worked, they didn't bother coming up with a catchier name. They just wrote "WD-40" in the lab book and called it a day.

From Missiles to Your Toolbox

The first customer wasn't a hardware store—it was Convair, an aerospace contractor that used WD-40 to protect the outer skin of Atlas Missiles from rust and corrosion. Turns out, keeping rockets from rusting in coastal California was serious business.

Employees at Rocket Chemical kept sneaking the stuff home because it worked so well on everything. The company caught on and started selling it in aerosol cans to the public in 1958. By 1961, WD-40 was on store shelves nationwide.

The Secret's Still Secret

The original formula is still a trade secret, locked away and known by only a handful of people. It's never been patented—because patents require public disclosure, and WD-40 Company would rather keep competitors guessing.

There's some mystery about who actually invented it. One story credits Iver Norman Lawson, who allegedly developed the mixture at home and sold it to the company for $500. Another version says Norman Larsen, the company president, created it. Either way, whoever cracked that 40th formula created something used by millions.

More Than Just a Lubricant

Here's the thing: WD-40 isn't actually a lubricant, despite how everyone uses it. It's a solvent. The "water displacement" part is the whole point—it pushes moisture away from metal surfaces and leaves behind a light film. That film happens to reduce friction, which is why it seems like lube, but it's not designed for long-term lubrication.

People have found over 2,000 documented uses for WD-40, from removing crayon from walls to protecting guitar strings. The company even published a book of user-submitted tips. None of those 2,000 uses include protecting missiles anymore, but the water-displacing chemistry that started it all still works exactly the same way it did on attempt number 40.