Resists: wash marring
The fine scratching from mitts and towels. A coating is harder than clear coat and dirt releases more easily, so there is less dragging.
This is the real, meaningful scratch benefit, and it compounds over years.
No. A ceramic coating is more scratch-resistant than bare clear coat and it is only microns thick. It reduces the light marring that comes from washing. It does nothing against a key, a door edge, a shopping trolley or a stone off a lorry.
The hardness figures used in coating advertising are measured with a pencil-hardness test on a flat panel. They say something real about resistance to gentle abrasion. They say nothing at all about impact, and no coating manufacturer claims otherwise in their technical data.
This is the claim we get asked to confirm most often, and the honest answer costs us sales. We would still rather you buy a coating for what it does than for what it does not.
The fine scratching from mitts and towels. A coating is harder than clear coat and dirt releases more easily, so there is less dragging.
This is the real, meaningful scratch benefit, and it compounds over years.
Bird droppings, tree sap, acid rain, salt film. These land on the coating rather than the paint.
In this city that is arguably the biggest single benefit.
A barrier over the clear coat slows fading and chalking, particularly on a car parked outside.
Rock chips, stones off the road, gravel. Microns of coating do nothing against kinetic energy.
Paint protection film is the product for that — a physically thick, self-healing layer, and a different service entirely.
Keys, door edges, trolleys, bumper scrapes. Anything that would scratch clear coat scratches straight through a coating.
A tunnel wash will scratch a coating. It raises the threshold; it does not remove it.
See the tunnel wash guide.
You will see coatings advertised as 9H. That figure comes from a pencil hardness test: pencils of increasing hardness are drawn across a coated surface at a fixed angle and load, and the rating is the hardest pencil that does not mark it. 9H is the top of that particular scale.
It is a real measurement of a real property — resistance to gentle abrasion by a hard point. It is genuinely relevant to wash marring, which is exactly that kind of damage at a smaller scale.
What it is not is a measure of toughness, impact resistance or thickness. A pane of glass is hard and shatters. The pencil scale tops out at 9H, so a coating that is far harder and one that just clears the bar both advertise the same number.
It is also worth remembering the scale of the thing. A ceramic coating is typically a couple of microns thick, on a clear coat of 40 to 60 microns, on a car. It is a chemical barrier and a wear layer, not armour, and the honest way to think about it is as a very durable replacement for wax rather than as protection in the physical sense.
Everything on this list is a genuine reason to buy a coating. Notice that none of them are about stopping physical damage.
If your genuine worry is stones off the freeway hitting the front of the car, a coating is not the product for that and we will tell you so rather than sell you one.
The product for impact is paint protection film — a thick, clear urethane film applied to the panels most exposed to stones, typically the bonnet, front bumper, wing mirrors and A-pillars. It is physically thick enough to absorb an impact that would chip paint, and most modern films self-heal light scratching with heat.
It is a different service with different economics, and it is not something SF City Wash offers. We are not going to imply a ceramic coating substitutes for it.
What a coating does do for a car that already has chips: nothing to the chips themselves, and it will not fill them. Chips are missing paint, and adding a transparent layer over a hole does not close it. If chips bother you, they are a touch-up or bodywork question, addressed before any coating goes on.
For everything that is not impact — the chemical attack, the UV, the wash marring, the salt — a coating is genuinely the right tool, and that covers most of what damages a car in this city.
If you want a coating because your car lives outside, gets rained on, sits under trees and picks up salt, that is exactly what it is for and it will do the job for years.
If you want one because you are worried about door dings or stone chips, save your money. We would rather tell you that now than have you disappointed in six months.
More short answers live on the FAQ.
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For chemical attack, UV and wash marring it is the best thing available. For impact, nothing microns thick helps.