I don't think any professional detailer who has posted here say that adding a spray/wax type product "hurts" anything. For ceramic coating, you would probably have to go out of your way to find any detailing product that damages the coating.
Rather, adding another layer of wax (or anything) will take on the characteristics of that coating. If that's what you want, then fine, but why did you spend all that money for ceramic? Also, anyone who has a ceramic coating can testify that it outshines most wax coatings, so in a way you can degrade the finish... but you won't be damaging anything. This has been posted in this thread several times.
;tldr It won't damage or strip anything, but it may degrade the shine.
This. You can use any auto shampoo you desire, any drying aid you like, any quick detailer or spray wax you like and it will not HURT your coating, nor will it strip it. What it will do is cover up/mask your coating until it wears off which will be rather quickly given the coatings inherent properties at rejecting contamination.
You likely had your car coated for protection, self cleaning and hydrophobic properties. Covering these properties up with wax, polymers, sealants or anything not formulated for a coating, while not hurting the coating or weakening its protection, is like throwing a blanket of lesser performing material on your paint.
You can use any car care maintenance product you like on your coated car without fear of damaging or stripping it but once you step out of the arena of things that are formulated specifically for coatings, you'll be diminishing the performance of your coating; not permanently, not dangerously but why do it? Just grab a different bottle/product, one that is made to maintain and enhance your coating instead of temporarily covering it up.
Ceramic coating is one type of coating, a layer that seals your paint for protection, like wax, sealant etc. But some ceramic coatings claim they are 9H. It is a scale for hardness ranging from 1H-10H. 10H is diamond. It implies that ceramic coating is really strong.
In general, when you wash your car, ceramic or not, make sure there you first clean/rinse off dirt and particles to avoid scratches and swirls. That's what we recommend people when they wash Suma Mirrors, protecting the special GEL.
I believe you are confusing the MOHS scale of mineral hardness with the Pencil Test to determine hardness, the test coating mfg's use to reach their somewhat pointless claims of hardness. 10h on the pencil test is not equivalent to diamond but rather the 'hardest' graphite pencil they have come up with, essentially 1.5h on the Mohs scale where a diamond is indeed 10h. If coating mfg's used a consistent scale such as Mohs they'd all be touting "1.5h hardness" which probably doesnt look as good in their marketing materials.
Claims of hardness, scratch resistance and such are, IMO, way over-marketed with coatings. While they may provide some minor resistance to light marring, it’s a harsh world out there and many things (jewelry banging paint around door handles, boxes hitting trunk areas while loading, leaning on hood of vehicle with grimy sweatshirts, etc) *will* leave a mark. Problem with coatings is the only way to remedy those marks/marring is to re-polish (removing coating) and re-coating that area, generally an entire panel as many coatings don’t lend themselves well to spot fixes. If you’re horribly OCD-ish about having a totally defect free car for 2 years, a coating may not be the best way to go…or a ‘lighter’ coating like Gyeon CanCoat may be more appropriate.
Additionally, while trying to wrap my my around it I kinda came up with the following to help understand it in my SiO2 addled mind:
It’s all nonsense marketing. My 2h fingernail will leave a mark on a 10h coating.
The ‘h’ hardness can be measured in 2 different ways...
The Mohs scale of mineral hardness is a scale characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material.
The Pencil Hardness test employs various graphite pencils of varying hardness to determine the h-hardness measurements. Since even the hardest pencil is still made of graphite (Mohs hardness of 1-2) it seems possible (to me anyway) that even a 9h coating (as measured by the pencil test) is really, comparably, at most a 2h hardness and thus quite easily scratched.
For the purposes of coating hardness, perhaps considering the pencil test a subset of the Mohs test which, although kinda a generalization may be useful for comparative purposes. The pencil test, based upon graphite testing pencils, then translates into a subset of the Mohs
MOHS Scale with Pencil Test Subset (and yeah, I just kinda made this up based upon info I could find)
MOHS Hardness
1 Talc
1.5 Graphite
Pencil Test Subset applicable to coatings using graphite pencils:
---1h
---2h
---3h Average Automotive Paint
---4h Average Automotive Paint
---5h
---6h
---7h
---8h
---9h
---10h
2 Gypsum
2-2.5 Fingernail
3 Calcite
4 Fluorite
5 Apatite
6 Orthoclase feldspar
7 Quartz
8 Topaz
9 Corundum
10 Diamond
So, given that coatings are measured using the pencil test (graphite) there is no way for a coating to be any harder than 2h measured on the Mohs scale while a fingernail is 2-2.5h on Mohs
Fingernail – 2-2.5h (Mohs)
Clearcoat – 3-4h (Mohs equivalent 1.5h)
A 9h coating – 9h (Mohs Equivalent 1.5h)
While a coating is indeed slightly harder than the generally accepted toughness of clearcoat, the actual difference is likely very, very, VERY small and my fingernail will still goon up a vaunted 10h coating.
So, while a mfg can claim that their 9h coating is ‘more than twice as hard’ as your clearcoat, it’s really not saying much.
Of course there are more than a few other variables that enter into the equation of scratch resistance (substrate hardness, for one) but, for me, the benefits of coating are the resistance to environmental and the self-cleaning characteristics. I stopped caring about scratch resistance long, long ago.