[SnakeEyeSS]

So, anyone that has researched it knows that the H rating is marketing.

When I picked up the very cheap ceramic I plan on testing out this week, the guy was trying to upsell me as I mentioned in another thread, his key point was "but XXX is 9H, this company doesn't even claim a hardness rating. " Which didn't bother me. How many "scratch resistant 9H" screen protectors have I gone though, when the wet film applications don't claim it and are much more scratch resistant. I know, maybe apples to oranges, but marketing is marketing.

I was curious how the companies come up with some of it and found this.

https://www.feynlab.eu/2018/05/07/th...dness-testing/

But if you take a more subjective look you will see that they have coated a steel plate and ran it through the test, it results in a very high number.....these coatings are usually less than 5 microns and there is no-way you would get a reading of the film hardness. You are testing the hardness of the steel underneath the coating.

Anyone else know of another good "explaination"?

People still get sold on the marketing, I would like to collect a thread we could point people to on what is real and what is marketing.

[Gunkk]

The Feynlab article is correct: The "H" rating used in ceramic coatings is good ol' fashion Marketing Bull$#!t (TM).

I'm going to talk mostly about Mohs hardness here and not so much (the pencil test which uses a different scale that also contains "#H" ratings). It's very easy to confuse the two since both contain a "9H" rating, and I'm sure many coating companies are doing it on purpose rather than out of ignorance. Particularly Geyon who has a product called "Mohs" and claims it has a 9H rating.

The Mohs hardness "H" rating scale pictured below is based on relative hardnesses of various minerals from Talc to Diamond. If a mineral such as quartz can make a scratch in another mineral such as Feldspar, then it's a higher hardness.

9H is Corundum, which is crystalline Aluminum Oxide (Al2O3), also known as sapphire ruby, emerald, etc. (color is based on presence of trace elements). High end watches (Rado, Cartier, Rolex, etc.) use sapphire for the watch face cover glass due to its scratch resistance.

Only Diamond is harder than 9H.

7H is Quartz, or crystalline Si02. Common window glass is typically borosilicate glass that is not crystalline, so it's a bit softer than 7H.

So if you want to do an experiment like Mohs did, take a piece of common window glass (slightly softer than 7H quartz) and drag it across your ceramic-coated paint. Who wants to lay odds that the coating will prevent you from scratching the paint? This is also the case for every other mineral on this scale except maybe Talc. So do you think the ceramic coating on your car is Mohs 9H now?

FWIW, the Pencil (i.e. compressed graphite) hardness scale below was originally created for woodworking finishes. Pencil hardness hovers around the Talc level on the Mohs scale, where 9H on the pencil scale might be between 1H and 2H on the Mohs scale, and the softest "9B" ratings on pencils will likely be below at or talc (0-1H Mohs). Here's another article on pencil hardness: https://blog.iglcoatings.com/coating-scratch-hardness/

Car coatings are far more likely to align to the Pencil Hardness scale, where a good cured coating may indeed resist scratches from hard pencils. This is more likely to be as much due to the smoothness and "thin-ness" of the coating as its molecular composition. The bare OEM factory paint is already going to be very high up on the pencil hardness scale so you're not likely to see a difference using a pencil test. Furthermore the coatings also contain other silicones, siloxanes, and pixie dust for hydrophobicity that have strong lubricating effects. So as your pencil tip (or rag with dirt particles) drags across a ceramic or hydrophobic coating, it's more likely snow plowing up a bunch of polymer on the edges of the hard microscopic dirt particles that's acting as a lubricant between the paint and the pencil/dirt, preventing scratches. Just like oil inside your engine lubricates the journal bearings. I'll see if I can find the video of the guys who were polishing (or wet sanding off?) some coatings and their pads were getting fouled, slowing down the removal process.

[Gunkk]

Here are a couple more interesting reads on the subject:

https://carproforum.com/showthread.p...ull=1#post7304

https://www.reddit.com/r/teslamotors...ff_on_ceramic/

[KirkH]

Good info.

[indyz]

Interesting stuff. Subscribed.

[KirkH]

More info on this subject:

https://www.detailedimage.com/Ask-a-...s-2-05-30-2019