What Does WD-40 Stand For, And What's In It?

WD-40 is one of the most useful multi-purpose products you could have in your garage or toolbox. The name "WD-40" has become synonymous with handiwork, degreasing, and lubrication in the same way that "Band-Aid" has become synonymous with first aid. If you went into a hardware store and asked for some WD-40, you'd almost always get their standard Multi-Use spray, or a similar product with the same function.

When a product becomes so recognizable, though, it eventually reaches a point where it loops back around and becomes unrecognizable. WD-40 may be synonymous with lubrication, but only because everyone knows it as "that stuff that's good for lubrication." 

WD-40 actually has quite an interesting history behind its name and intended function, dating all the way back to the 1950s. Let's trace the thread of history back to the origin of WD-40, and cover what gives the compound its distinct lubricating mojo.

WD-40, obviously, has a name composed of two parts. The first "WD" part stands for "Water Displacement." You know how when you drop something into a glass of water, the water level rises? That's an instance of water displacement — physical matter pushing water out of the space that it's currently occupying. WD-40 works the same way, albeit in a liquid form that other liquids like oil can't mix with. WD-40 fills the space, forcing greasy substances away.

As for the "40" in "WD-40," that ties into the legend of the product's initial creation. According to WD-40's official history, the original "Multi-Use" formula was concocted in 1954 by the Rocket Chemical Company in San Diego, California. 

This company was looking to make it big by creating a substance that could work as a degreaser and rust-buster to sell to the burgeoning aerospace industry. However, it allegedly took the research team 40 tries at a viable formula before they got it right. That's quite a herculean effort, and as it turns out, it makes a great brand name.

WD-40's precise formula is a closely guarded trade secret. Back in 2018, the original formula — which is written on a single piece of scratch paper — was transported to a secure vault in a San Diego bank via armored transport. The company even went as far as to purposely skip patenting the formula just so they wouldn't have to publicly disclose the ingredients.

All that said, based on similar products and available Material Safety Data Sheets, we can extrapolate two standout ingredients. The first is a petroleum base, likely forming the bedrock of the formula. Simple petroleum oils are safe to handle with bare hands, plus it's hydrophobic, so it won't mix with other liquids. The other major component is hydrocarbons: a combination of hydrogen and carbon, and are a common sight in solvents, which are used to dissolve the molecular bonds between sticky things and solid surfaces.

Put these two ingredients together, and you've got a liquid substance that can unstick the sticky without mixing with it. It's probably a lot more complicated than that, but without knowing the full formula, that's about as much as we can guess at. The point is that it just works.