Hardness – What does it really mean?

Many companies like to dwell on the hardness rating, such as 9H. Some even include it in their product’s name to draw attention to it. What most of them are not advertising is what 9H actually means. The test used to determine the film hardness that is advertised for every coating I have seen to date is known as the “Pencil Hardness Test”. As I understand it, this test consists of a variety of standardized grading pencils that range from soft to hard depending on the composition of the pencil. Using a pencil, a line is made on the surface that is being tested, and if no scratch is visible, the test is repeated with a harder pencil until the surface is scratched. A coating with a hardness of 9H does not show a scratch with the hardest pencil.

This is far different than the MOHS Mineral Hardness scale in which minerals are rated on a scale of 1-10, where 1 is the softest and 10 is the hardest. In the past, I have seen detailers advertising products with a 9H MOHS hardness, however this is simply not feasible. If a coating had a mineral hardness of 9H, the only substance that would be able to scratch the surface would be one with a hardness of 10H or greater. For reference, a diamond, one of the hardest substances on earth, is rated at 10H. With that in mind, if a coating was truly 9H mineral hardness, it would not be possible to scratch the car with a key and you certainly would not be able to make swirl marks with a dirty towel (unless you’re smashing up diamonds and sprinkling them onto your towels).

Once a coating is applied, it can be scratched and swirled just the same as bare paint, so do not read too far into the hardness claims that are listed with any particular coating. In my opinion, they are nothing more than marketing hype.

Never Polish Your Car Again!

Say goodbye to swirls and scratches! … I wish. You know what they say, if it sounds too good to be true, it probably is.

Unfortunately, this is another completely false claim that is being used to lure customers in. While paint coatings may theoretically provide some small amount of resistance to fine marring, they are certainly not scratch proof or swirl proof, and improper washing and drying will absolutely lead to swirls and scratches on a coated vehicle. We typically recommend having a coated vehicle polished and re-coated every 2-3 years or so to maintain the highest gloss and clarity. A well maintained vehicle should only require very light polishing, never true correction, regardless of what type of protection has been applied.

Clear coats are very sensitive, and sometimes it seems like no matter how careful you are, it is impossible not to leave behind some very light marring or swirls after washing and drying. Paint coatings are typically harder than your vehicle’s clear coat. This added hardness helps to protect your paint from light marring. Remember, coatings can still easily be scratched, however they can help to reduce the amount of lighter defects from appearing over time. This means you will need to polish your vehicle less often.