WD-40

This article is about the lubricant. For the company that makes it, see WD-40 Company. For the biomolecular structure, see WD40 repeat.

WD-40

WD-40 with Smart Straw
Product type	Penetrating oil
Owner	WD-40 Company
Country	San Diego, California, United States
Introduced	1953 (1953)
Website	www.wd40.com

WD-40 spray can from Germany

WD-40 is the trademark name of a penetrating oil and water-displacing spray. The spray is manufactured by the WD-40 Company based in San Diego, California.

History

Different sources credit different men with inventing WD-40 formula in 1953 as part of the Rocket Chemical Company (later renamed to WD-40 Company), in San Diego, California; the formula was kept as a trade secret and was never patented.

According to Iris Engstrand, a historian of San Diego and California history at the University of San Diego, Iver Norman Lawson invented the formula, while the WD-40 company website and other books and newspapers credit Norman Larsen. "WD-40" is abbreviated from the term "Water Displacement, 40th formula", suggesting it was the result of the 40th attempt to create the product. The spray, composed of various hydrocarbons, was originally designed to be used by Convair to protect the outer skin which comprised the paper-thin balloon tanks of the Atlas missile from rust and corrosion. These stainless steel fuel tanks were so fragile that when empty they had to be kept inflated with nitrogen to prevent them from collapsing. WD-40 was later found to have many household uses and was made available to consumers in San Diego in 1958.

It was written up as a new consumer product in 1961. By 1965 it was being used by airlines including Delta and United; United, for example, was using it on fixed and movable joints of their DC-8 and Boeing 720s in maintenance and overhaul. At that time, airlines were using a variant called WD-60 to clean turbines, removing light rust from control lines, and when handling or storing metal parts. By 1969 WD-40 was being marketed to farmers and mechanics in England.

Function

The long-term active ingredient is a non-volatile viscous oil which remains on the surface to which it is applied, giving lubrication and protection from moisture. This oil is diluted with a volatile hydrocarbon to make a low viscosity fluid which can be aerosolized to penetrate crevices. The volatile hydrocarbon then evaporates, leaving behind the oil. A propellant (originally a low-molecular-weight hydrocarbon, now carbon dioxide) creates pressure in the can to force the liquid through the can's nozzle before evaporating.

Its properties make it useful in both domestic and commercial settings. Typical uses for WD-40 include removing dirt and extricating jammed screws and bolts. It can also be used to loosen stubborn zippers and displace moisture.

Due to its low viscosity, WD-40 is not always a suitable oil for certain tasks. Applications that require higher viscosity oils may use motor oils. Those requiring a mid-range oil could use honing oil.

Formulation

WD-40's formula is a trade secret. To avoid disclosing its composition, the product was not patented in 1953, and the window of opportunity for patenting it has long since closed. WD-40's main ingredients as supplied in aerosol cans, according to U.S. Material Safety Data Sheet information, are:

• 50% "aliphatic hydrocarbons". The manufacturer's website claims this ratio in the current formulation cannot accurately be described as Stoddard solvent, a similar mixture of hydrocarbons.
• <25% petroleum base oil. Presumably a mineral oil or light lubricating oil.
• 12–18% low vapor pressure aliphatic hydrocarbon. Reduces the liquid's viscosity so that it can be used in aerosols. The hydrocarbon evaporates during application.
• 2–3% carbon dioxide. A propellant which is now used instead of the original liquefied petroleum gas to reduce WD-40's flammability.
• <10% inert ingredients.

The German version of the mandatory EU safety sheet lists the following safety-relevant ingredients:

• 60–80% hydrogen-treated heavy naphtha (a petroleum product used in wick-type cigarette lighters)
• 1–5% carbon dioxide

It warns of the product's high flammability and the risk of irritation to human skin when repeatedly exposed to WD-40. Nitrile rubber gloves and safety glasses should be worn (ordinary rubber disintegrates if exposed to petroleum products). It also mentions that water is unsuitable for extinguishing burning WD-40.

In 2009, Wired published an article with the results of gas chromatography and mass spectroscopy tests on WD-40, claiming that its ingredients make it resistant to freezing.

External links

• Official website
• WD-40 Material Safety Data Sheet
• WD-40 uses, by Snopes.com

• Martin, Douglas. "John S. Barry, Main Force Behind WD-40, Dies at 84". The New York Times, July 22, 2009.
• Changing Times (pre-1986) 15.5 (May 1, 1961): p 36.
• wd-40-multi-use-product-aerosol
• What is Honing Oil? Complete Multi-tool Sharpening Kit. Swiss Army Supplies Website. 2011. Retrieved December 8, 2012.