Moisture was the enemy. Even small amounts of water could compromise sensitive metal parts, and failure wasn’t an option.
The project was led by chemist Norm Larsen, whose goal was not to invent a multi-purpose spray, but to create a formula capable of completely displacing water while leaving behind a protective coating on metal surfaces. The team worked methodically, testing formula after formula.
The first attempt didn’t work.
Neither did the second.
Or the third.
In fact, thirty-nine attempts failed to meet the strict requirements of aerospace and defense engineering.
Then came the breakthrough.
The Meaning Behind the Name
The fortieth attempt succeeded.
And that success is permanently embedded in the product’s name.
WD stands for Water Displacement
40 refers to the 40th formula
There was no branding trick or clever marketing spin—just a straightforward description of how the product came to be. Few consumer products are so literal in their naming, and even fewer wear their trial-and-error history so openly.
