There are several shade-tree solutions to common, everyday problems. One of the most popular is using penetrating oil or WD-40 to loosen rusty bolts, extend the lifespan of windshield wiper blades, or even a universal cleaning solution. But did you know that many car owners swear by its ability to fix small scratches, or reduce bugs from sticking to car paint?

People use WD-40 or other generic penetrating fluids for multiple reasons. But is it safe to use on your car’s paint job? Are there risks to applying it to a clearcoat, glass, or other exterior automotive materials?

These are questions we’ll answer in today’s AvalonKing blog.

What is WD-40?

In case you’ve been in a coma or just not too mechanically inclined, WD-40 is a penetrating fluid or lubricating oil that was created in the 1950’s. It’s pretty much the go-to solution for loosing things that are stuck or providing lubrication to something that needs some.

Here is a cool bit of trivia. It’s first application was used as a spray coating on a missile built by Convair to reduce rusting and corrosion.

You’ll find WD-40 in the garage or under the kitchen sink in more than 60% of households in the United States. So, to say it’s a popular product would be an underestimate. Around the house, it’s used mainly to loosen metallic parts that have been corroded or are stuck with excess oxidation (or rust).

In the garage, you’ll find many mechanics and machinists using it as a lubrication spray, as they cut metal. The special ingredients help to dispel heat, making the cuts cleaner and with fewer jagged edges.

What is WD-40 Made From?

So, where did the name WD-40 come from? The WD is an abbreviation for Water Displacement, or the primary task it accomplished. The formulation helps to displace moisture from surfaces – so the WD makes sense. As for the 40, that’s the amount of formulations or attempts to create a final solution that worked as intended.

Doing This With WD-40 Will Save You Thousands in Car Repairs

Now, let’s dive into the formulation – or what makes WD-40 the perfect all-in-one removal solution. Unfortunately, the official recipe is a highly-guarded secret on par with Coke or KFC’s “11” herbs and spices. However, thanks to Material Data Safety Sheets published on the internet, it’s not that hard to come close.

There are four primary ingredients – with the percentages being the proprietary information.

  1. Aliphatic Hydrocarbon (which is similar to kerosene)
  2. A petroleum-based paraffin
  3. Flammable aliphatic hydrocarbons
  4. Carbon Dioxide

There are trace elements including mineral oils and alkanes of carbon. When you combine all these ingredients in the percentages that WD-40 has perfected, you get a highly-impressive anti-squeak lubricant spray.

Why Would you Want to Use WD-40 on Car Paint?

Now we’ll dive into the nitty gritty of this article – why it’s commonly used on car paint – and whether that’s a good idea. Let’s start with the why. WD-40 is similar with many car polishes, in the fact that is contains oils and hydrocarbons that allows the formulation to seep into small areas. It also has anti-corrosive agents that can reduce the potential of oxidation.

This introduces the main purpose for using it on your car paint – to fill deep scratches. Now, let’s be clear, this doesn’t mean fixing the scratch. It’s basically a quick way of putting a band-aid on the scratch, to ensure that water does not find its way into the bare metal – leading to the development of rust.

However, car owners are creative cats, and over the year, WD-40 has been used on a cars surface for several other purposes.

As a Color Enhancer

There are some car owners who use WD-40 as a wax – which amplifies the luster of paint. When it’s sprayed on top of paint with a clear coat, the paraffins in the solution produce a shiny hue – which can replicate the shine you get from a fresh coat of wax.

Improve Hydrophobic Properties

It’s also a common shade-tree treatment for improving hydrophobic properties on non-protected paint surfaces. Car owners will spray it on the surface to help reduce the potential of bugs, bird droppings, tar, and tree sap from sticking to paint. It also can bead water fairly-decent as well.

Removing Oil & Bug Guts

Bug splatters and other sticky debris is easy to remove with WD-40. A simple spray, letting it soak for a few minutes, and then wiping off will take care of most stuck on debris.

Likewise, that annoying valve cover or seal leak under the hood is pissing you off, a few sprays of WD-40 will clean up that splattered oil quickly. Since it’s a degreaser, WD-40 is great for removing those pesky water-insoluble substance including grease.

Extend the Lifespan of Wipers and Gaskets

The main reason that door trim gaskets and windshield wipers wear out is frequent exposure to the elements – like UV rays or oxygen. As they age, the gasket material will begin to dry, eventually crack, and then begin to fail. Some people use WD-40 to keep these items protected from the elements by spraying some on a cloth, then wiping onto the rubber materials.

Great for Spark Plug Maintenance

If you’re a DIYer, and complete your own maintenance, you’ve likely used WD-40 as a helpful tool when cleaning spark plugs. As plugs age, it’s common for condensation to collect on the spark plug, which leads to poor spark performance. If you’re having condensation issues with an older engine with weak internal seals, a quick spray of WD can help your starting issues.

The Universal Cleaning Tool

Annoying rust on your license plate frame, corrosion on steering and suspension parts, or caked on debris under the hood is easily removed with WD-40. In fact, there are several car owners who use this product and duct tape for vehicle maintenance.

Is WD-40 Safe to Use on Paint?

WD-40 is filled with a lot of products when applied to car paint alone – can be harmful to paint. For example, kerosene (which is similar to the primary ingredient) can eat through even the hardest clear coat in a matter of days.

However, due to the brilliant mixture and blend of ingredients – Yes – it’s SAFE to use on paint. But, as we’ll describe in the information below, it’s just not a smart idea.

When You Shouldn’t Use WD-40

I’m going to preface this paragraph by saying that I was raised to fix things broken, not put super glue or a band-aid on them. That said, WD-40 should only be used as a penetrating fluid to help you loosen rusted, corroded, or fused bolts, nuts, and other fasteners.

It’s typically assumed that using it for bike chains, on door jams, and other moving parts is more than acceptable. And as a one-time quick fix, that is accurate. However, here is the downfall of WD-40, and a main reason why using it on car paint is likewise not a smart idea.

The oils found WD-40 are notorious for collecting dirt, dust, debris, and other contaminants. This makes the items you’re spraying WD-40 sticky, dirty, and in the case of a moving part – like hinges or chains, may cause them to bind-up.

With car paint, that scratch that is exposed might be protected for a day or two. But by then, the area will be so dirty, you’ll have to wash it off. When this happens, you’ll find removing a nearly impossible task.

What Soap to Use to Wash WD-40 Off Your Vehicle

If you’re in the inevitable situation of having to wash WD-40 off your paint, there really is only one good method. You’ll want to use an automotive detergent car shampoo – which is commonly known as a wax-stripping or prep shampoo.

The decontamination car shampoo is a pH strong formulation, meaning is a strong base – which acts as a detergent to penetrate oils that are found in waxes, sealants, and yes – WD-40.

When you use a foam gun to apply onto the paint surface first, it can sit on the car and agitate for a few minutes. This action helps to break down the lubricants in WD-40, and the caked-on dirt and crud stuck to it.

Wrapping it Up

WD-40 is one of those miracle solutions like Velcro and duct tape that simply makes life much easier. However, it’s got an intended use and purpose. By using it as a scratch repair, for improved hydrophobic properties, or to fix that fouled spark plug, you risk creating more problems down the line.

If you’re in a situation where you’ve developed a scratch, have condensation in your combustion chamber, or looking to protect your paint, it’s always smarter to find the root issue, and fix it. While WD-40 and duct tape can save you’re butt from a troubling situation, it’s just not a smart long-term solution.

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