As an auto appraiser, I have often wondered if WD-40 is safe to use on car paint or whether it would hurt the finish. Scrapes and scuffs on the paintwork of a car are frequent. Sometimes, it is not until you start to handwash your car that you notice the imperfections. If you don’t have car polish or a paint pen, would WD-40 work? Or would it harm the car’s paint?
WD-40 is safe and will not hurt your car’s paint job. WD-40 is mineral oil-based and actually adds additional corrosion protection to the finish and protects the clear coat. Just make sure you wipe off the excess or your vehicle may look greasy and attract dust easily.
WD-40 is a common household item that has more uses than you may realize. It is commonly used instead of car polish to fill in smaller scuffs and scraps on car paintwork. Furthermore, WD-40 is excellent at removing dirt, bird droppings, bugs, and tar. It is entirely safe to use not only on car paint but also on most car surfaces, including interiors.
Why Will WD-40 Not Harm Your Paintwork?
WD-40 does not contain anything that will harm your car’s paintwork. Although the exact ingredients are a trade secret, we know that it is a unique blend of lubricants. In fact, the manufacturers opted not to patent the formula back in the 1950s to protect their secret blend. The WD stands for water displacement, and its primary function is to displace moisture from surfaces. The 40 comes from 40th – therefore, this was likely the 40th attempt at making a suitable mixture.
Despite the secrecy around its formula, we have some ideas as to what it contains due to disclosures needed for the material safety data sheets (MSDS) that all chemicals need to have before it is distributed. From the MSDS, we can discern that WD-40 contains:
- 45-50% of an aliphatic hydrocarbon like kerosene, to create a low vapor pressure
- <35% of heavy non-hazardous kinds of paraffin which come from petroleum-based oils
- <25% of flammable aliphatic hydrocarbons
- 2-3% of carbon dioxide, to make WD-40 into a propellant
Aliphatic hydrocarbons are those that do not contain aromatic rings in their structure. This makes them easier to break down and are often flammable. Further chemical interrogations of WD-40 demonstrated that it mostly contains relatively small alkanes of C9 to C14 and mineral oil. For reference, methane, the simplest alkane, has four carbons. Mineral oil is derived from petroleum. Therefore, the chemical composition of WD-40 is non-reactive with car paint and is perfectly safe to use.
Originally, WD-40 was manufactured for the American aircraft company, Convair (previously Consolidated Vultee). Its purpose was to coat the exterior of their Atlas missile, to protect it from rust and corrosion. As its intended purpose is precisely the same as using it on car paint, it is unsurprising that WD-40 will not destroy the paintwork.
A few years after its invention, WD-40’s utility was noted, and it was widely released to the public in 1958.
As its intended purpose is precisely the same as using it on car paint, it is unsurprising that WD-40 will not destroy the paintwork.
Why Would you Want to Use WD-40 on Car Paint?
WD-40 is very similar to car polish and has many properties that make it an attractive product to use on your car.
When sprayed, the viscous oil and alkanes spread over the surface. The hydrocarbons allow the oil to wick into small areas, such as scratches or crevices on your car’s paintwork. Over time, the hydrocarbons evaporate, leaving the lubrication oil blend behind.
The WD-40 mixture also contains anti-corrosive agents. The mix of oils and anti-corrosives protects your paintwork by replacing the topcoat that was lost when it was scratched. Ultimately, this will protect the lower paint layers, keeping the color vibrant.
The chemical properties of WD-40 also make it an excellent substance for protecting your paintwork from getting dirty. The same fine layer that fills in imperfections also coats the paint with a water-resistance layer. As a result, bugs and grease build-up at a far slower rate than when WD-40 isn’t applied.
Once the dirt has built up, WD-40 is excellent at removing dirt, grease, bird droppings, dead bugs, and even paint transfers. It is gentle on the paint surface as you scrub with it as the blend does not contain any abrasive components. Instead, the chemical mix gets underneath the stain to softly lift the dirt or stain away. I recommend uses the foam version (click to see Amazon listing), if you want to use it as a protectant
Once you have use WD-40 on your car, you will want to wash your car with soap and water to remove all the excess oil. Otherwise, it will attract dust very easily.
WD-40 Can Help More than Your Car’s Paintwork | 5 Other Uses
- Keep the bugs and dirt away
As WD-40 coats the surface with a lubricant, it is effective at creating a shield against flying bugs and mud. Spray WD-40 onto your windshield and your car’s grill, and it will stop dead bugs or mud sticking to your vehicle.
- Clean oil
WD-40 is a degreaser. Therefore, it will remove water-insoluble substances like oil. It is excellent for spills occurring during an oil change, whether it is on your driveway or hands. To clean, spray WD-40 on the affected area and wash it off. Once finished, rinse with soap and water.
- Prolong wipers and gaskets
By spraying your windshield wipers and the door gaskets (weather stripping) with WD-40, they retain their pliancy, which extends their lifespan.
- Spark plug maintenance
If your spark plug is having problems in wet weather, a common reason is due to the build-up of water. WD-40 will displace any moisture away from the ignition distributors and allow your car to start. Just don’t use it on brakes.
- Universal cleaning
Other than giving your car’s paintwork a shine, WD-40 can also clean your license plate, mudguards, tire sidewalls, etc. Almost every surface on the exterior of your car can benefit from an application of WD-40.
- Remove Stickers
I actually did an experiment recently to see if WD-40 would remove a sticker from a glass jar. It worked like a charm. Check out this video where I demonstrate. I’m sure this would work for stickers on cars as well. Just don’t rub or scrape harshly.
What Else Can WD-40 Be Used For?
WD-40 has a multitude of uses beyond cleaning and maintaining your car. Here are a few:
- Lubricate gardening tools
After spraying a shovel, trowel, hoe, or fork with WD-40, you will find that the soil comes off easily. This is especially useful when working with clay.
- Making stainless steel and tile sparkle
Due to WD-40’s chemical make-up, it will quickly remove stains from stainless steel and tiles. This can work a lot better than traditional cleaners.
- Unstick things
The lubricant in WD-40 makes it an excellent solution to remove things like chewing gum from carpet and hair, or by eliminating residual adhesives form various substrates. It is also great for trying to unstick Lego blocks. A good gardening tip is to spray the inside of pots before stacking them – they will come apart easier afterward.
- Remove rust
Spraying surface rust with WD-40 can help with its removal. It is best not to use it on surfaces you may eat from. It is best used for hand tools like a circular saw that have rust built upon them.
What Should I Not Use WD-40 For?
If you are like me, when you think of WD-40, you assume it is for uses related to squeaking chairs or perhaps a creaking door. As it transpires, they aren’t actually what WD-40 is designed for, and it really shouldn’t be used for these tasks. The main reason against it is due to how easily WD-40 attracts dust. Here are a couple of common uses that WD-40 isn’t the best product for:
- Squeaky Door hinges or desk chairs
The lubricants will eliminate the squeak for a while. However, Wd-40 attracts dust and other particles. Eventually, this will lead to black stains and grime building up on the hinge.
- Bike chains
You will have the same result – dust and dirt will adhere to the WD-40. This is dangerous as the chain can jerk and result in an accident/ For safety, use a bicycle-rated lubricant, which typically contains Teflon as a primary ingredient. However, many people do use WD40 on bike chains with anecdotal evidence that it works. But use at your own risk.
On some items, such as locks, WD-40 will increase the rate of wear and tear. Check before you use WD-40 on anything that to make sure it won’t corrode.
WD-40 is a combination of hydrocarbons and mineral oil. The product was designed to be used on paint to protect it from corrosion and rust. It will not harm your car’s paint can be used to cover up scrapes while helping to protect the surface from dirt, bugs, and bird droppings. Furthermore, WD-40 can be used to clean other areas of your car and help with the maintenance of bolts, spark plugs, and windshield wipers.
It seems there is no end to the uses for WD-40. People use it around the house to lubricate hinges and pretty much anything squeaky. Some people even swear by it when fishing! They spray it on their lures and are convinced that it attracts fish. The jury is still out on that one.
I hope you had fun reading this as much as I enjoyed researching the topic. Thanks for stopping by!
For more, don’t miss 6 Handy Alternatives to WD40.
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