I was told about a ‘scratch hack’ many years ago that removes light scratches from car paintwork, within seconds and cost virtually nothing. Sounds to good to be true right? I’m talking about the trade (no so) secret of the commonly used product WD40. I often wondered if it was true but never had a reason to find out. If I had a problem with paint, I would correct and protect it properly.

A little about WD40 first.

I was first developed around the early 1950s by Rocket Chemicals based in California who later changed their name on the basis of their product. The name WD40 stands for Water Displacement 40(th formula). The actual formula is a trade secret and only been held in secure vault in San Diego California since 2018. The product has not been patented to this day, to do so the ingredients would have to be disclosed. So if you want to copy it you could, if you try and reverse engineered like many others have and call it a different name.

The actual product hasn’t been changed for many, many years. The product was initially developed for a company to protect the outer skins of a super delicate skin of a ballistic missile from rust and corrosion. It later went on to find a host of household uses such as lubrication, protection and cleaning when it became commercially available in the very late 1950s. I won’t go into that side of it, you only have to look at YouTube or TikTok for various household hacks, from removing sticky labels, worktops, hinges, freeing up bolts etc.

I just want to look at this product from a car detailing point of view. It can be sprayed under the car to freshen things up, stop squeaks, apply a coating prior to winter to stop door rubbers sticking, short term storage or just polish up a bit. There are other products out there can do these dedicated tasks better than WD40, but not all of them together like this versatile ‘Jack of all trades’ product can.

Now of course there will be pros and cons for this ‘hack’;

The fact is that if you are spraying WD40 on anything, you are spraying an oil based type of product. Like I said in the cons, it’s only a quick fix and the old scenario of the car lot salesman showing you a gleaming car gives this hack a bad name.

The opportunity I had to try this hack out was that I had to remove a couple or stuck on hard plastic sill protectors on a car. Once they were removed it had left a couple of light scratches on the paint, even with my gentle panel removal tools. They are difficult to see but they are there.

So the tip so simple; spray a little on the paint and wipe over. Nothing could be easier, you don’t even have to rub it in just spread it about a bit.

The result is a miraculous cover up so the exposed paint could be seen again without the scratches.

So, does it work then? Yes – sort of

On the deeper scratches it improves it, but it doesn’t wipe them out. On lighter scratches does.

How? It’s all down the way light is reflected from the paint. The oil settles into the scratch and makes the light ray dispersion more uniform thus it disguises the scratch or swirl. This is a similar principle to car paint glaze which is a more durable option which needs a wax to protect it. I explain this paint defect principle in much more detail here. or cut and past this to your browser: htts://onemanandhismustang.com/difference-between-waxing-polishing-and-your-paint-job/

The general rule of thumb is if you can feel the scratch with your finger nail, you have a problem. If you can’t feel the scratch then it can be buffed, glazed or hidden in one way or another.

As the WD40 is oil it will eventually disappear due to the elements if on an exposed area. If the product is rained on a lot, it will need regular applications. So, if you want to mask or ‘hide’ a light paint surface imperfection, then you could use this product on a temporary basis. If you are going to buy a car, gently feel the paint to see if there is a oily film to the surface.

Another down side is that dust can settle in the WD40 spray and stick to it, so wiping it away could introduce more problems. The reason body shops don’t like it is the fact it’s oil based and once on your hands can be transferred all over the workshop. To clean it up properly in order to spray paint anything properly, this makes it all the more time consuming.

I tend to carry a small ‘sample’ sized can for a couple of reasons;

If you get a stone chip and can’t get to fix it for a while, spray the area with the WD40 and it will form a temporary barrier until you can fully remove it later to fix the chip.

If you are suffering from damp in your distributor cap (back to old school cars now) or HT leads etc, you can spray this to disperse the water. After all that was it’s sole purpose for development.

Did you know?

To get those super smoky burnouts in Hollywood films easily, they used an application of WD40 on the tyres! Not that you should ever do that of course, as it could be frowned upon by the local law enforcement agencies. 😉