What Does WD-40 Stand For?

May 9, 2023

wd 40

Got a squeaky door, a rusty hinge, or a bolt that just won’t come loose? There’s a good chance you’ve reached for this product; the liquid that magically loosens things up called WD-40. But why is this lubrication named WD-40? The reason for the name comes from the history of the product.

WD-40 is a solvent made with a special blend of lubricants. The WD in WD-40 stands for water displacement. Not only that, but the 40 means the 40th attempt at developing the product by the Rocket Chemical Company in 1953 in San Diego, California. The company was trying to create a formula to be used in the aerospace industry to prevent corrosion by displacing water, and they succeeded on the 40th try.

The product was first used to protect the outer skin of the Atlas missile from corrosion and rust, but employees of the company began sneaking the product in their lunchboxes to use in their own homes. Norm Larsen, the founder of the Rocket Chemical Company, thought everyday people in their homes could use it, and he later put it in an aerosol can and made it into a consumer product in 1958.

In 1969, the company that made WD-40, the Rocket Chemical Company, renamed themselves after their only product, WD-40, and the company went public in 1973. By 1993, WD-40 was said to be found in 4 out of 5 households in the United States, and more than one million cans were being sold per week.

The formula is still a secret that is locked in a safe in San Diego, California. The company acknowledges that WD-40 contains 50% mineral spirits but that the rest is a formulation of other special lubricants and anti-corrosion agents that are still a secret. It is said by the company that WD-40 has over two thousand uses.

Sources: WD-40 Company, WD-40, San Diego Air & Space Museum

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Daniel Ganninger - The writer, editor, and chief lackey of Knowledge Stew, the author of the Knowledge Stew line of trivia books, and editor of Fact World and the Knowledge Stew sister site on Medium, our ad-free subscription sites (you can find out how to join below). I hope you find things here to annoy those around you with your new found knowledge.

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