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WD‑40 has earned a reputation as a versatile household staple. Though marketed primarily as a lubricant, its applications span cleaning, insect repellant, and rust prevention—making it indispensable for tools such as rock saws.
While the number “40” might suggest 40 distinct uses, the product actually boasts over 2,000 documented applications, ranging from removing adhesive from leather to protecting shower grout from mildew, loosening stuck parking‑meter locks, and even erasing crayon from ceramics.
In fact, the name WD‑40 stands for “Water Displacement, 40th Formula,” according to the brand. This concise label reflects its original purpose and the perseverance that went into its creation, and its strong branding has made it a staple in nearly every American home.
The first two words, “Water Displacement,” point to WD‑40’s original goal: preventing rust that forms when water contacts metal. The “40th Formula” portion honors the 39 prior attempts that failed, highlighting the breakthrough achieved on the 40th try.
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WD‑40 was first formulated in 1953 by the San Diego‑based Rocket Chemical Company, a startup founded by Norman Larsen, Gordon Dawson, and John Gregory—each of whom served as the company’s sole employees. While media outlets often credit Larsen alone, Rocket Chemical’s website acknowledges all three founders as co‑inventors.
The original objective was to develop a rust‑prevention formula for the aerospace industry. Convair, an aerospace firm, became the first commercial user, applying WD‑40 to protect the Atlas intercontinental ballistic missiles—the United States’ inaugural ICBMs—from corrosion. Word quickly spread about its broader utility, leading to its mass availability in spray cans engineered by Larsen.
Developing the formula required 40 attempts, though details of the initial 39 iterations remain largely unknown. Today, the proprietary blend is guarded in a bank vault and has never been patented to avoid revealing its composition. The brand now offers several variants, including a silicone‑based lubricant, further expanding its versatility.
