Is silica dioxide content important in ceramic coatings?
Quick answer: Not on its own. A headline SiO2 percentage is mostly a marketing figure: it isn't standardised, and it tells you nothing about how the cured film actually behaves on your paint. Coating performance comes from formulation quality, the binders that hold it together, and the standard of application -- not the number on the label.
There's a fair amount of hype around silica content, as if it were some exotic ingredient that lesser companies skimp on to save money. Like most consumers, we get our information from marketing departments and salespeople; and, honestly, they often seem to know less about these products than we do. So before you let a percentage on a bottle make your decision, it's worth understanding what that number is actually telling you, which turns out to be very little.
The two claims you'll hear, and why neither holds up
We've heard the claim that a coating is inferior because it contains less silica. But is that really the reason, or is it because it's a product that mixes silica with wax, and the wax is the weak link? Retail products may well contain less silica; we doubt that's the sole reason they underperform. The wax or polymer carrier dilutes the film, behaves differently as it cures, and gives way long before the silica fraction would have been the limiting factor.
The opposite claim -- that a product is superior because it has the highest silica content -- is no more convincing. Would an extra pinch of silica really make a difference? If 1% more made the product better, wouldn't every brand be doing it? The honest reading is that "% SiO2" describes the proportion of silica precursors in the bottle before it cures, not the density or quality of the glass-like network that forms on the paint afterwards. Two coatings quoting the same figure can cure into films that behave nothing alike.
No builder claims their concrete is better because it has extra cement; we all know the mix needs to be right, with enough cement to do its job and the rest balanced around it. You can buy a bag of 100% silica online fairly cheaply, but nobody thinks that would make a better coating for your car. A coating is a recipe, not a single hero ingredient, and the part you can't read off the label is precisely the part that matters.
We remain highly sceptical, and we hope you will too -- it helps keep everybody honest.
What the number actually measures
"SiO2 content" is a marketing claim about the amount of silica precursors in a product. It isn't standardised across brands, it's rarely measured by an independent lab, and it doesn't tell you how the cured film will perform on the clear coat. One manufacturer might quote the figure as a percentage of the whole bottle including solvents; another might quote the solids only. There is no agreed test, so the numbers aren't even comparing like with like.
What does the work is the chemistry around the silica: the silane and siloxane binders, the cross-linking that turns a liquid into a hard film, and how cleanly that reaction completes on your particular paint in our particular weather. A ceramic coating cures into a tight network on the surface, and real-world durability comes from how well that network forms during curing, not from a single percentage on a label.
What we see across the bench
Because we're not tied to one badge, we get to apply a range of coatings and watch how they age on cars that come back to us for servicing. That's the part the spec sheet can't show you. Tom, our operations manager, will tell you the difference between two coatings on paper often comes down to a couple of points of quoted silica; the difference once they're on the car, eighteen months later, comes down to how the paint was prepared and how steady the conditions were on application day. We've watched a modestly specced coating outlast a higher-percentage rival on two similar cars, simply because one was laid down on properly decontaminated, fully corrected paint in a controlled bay and the other wasn't. The bottle didn't decide that; the preparation did.
Where it actually goes wrong
Chasing the highest SiO2 percentage ignores formulation and film formation entirely. People buy on the number, skimp on the bit that matters, and then wonder why the coating beads beautifully for a season and then sulks. The common traps are worth naming plainly:
- Treating "ceramic wax" and ceramic sprays as the same thing as a professional coating: they aren't, and mixing the categories buys you shorter life and different behaviour.
- Buying mystery bottles online on the strength of a big percentage, with no idea what carrier or binder is in them.
- Letting the headline figure stand in for the questions that count: who's applying it, and how is the paint being prepared first.
- Skipping decontamination and correction, after which no coating performs, regardless of what it cost or what it claimed.
How to judge a coating properly
Rather than shopping the spec sheet, choose the hands that apply it. A detailer you trust will have tested their preferred systems, knows how they behave in our climate, and will put a proven professional ceramic coating on your car. Preparation and application are where the difference is made now that most leading coatings are already excellent. Judge by the things you can actually verify after the fact: how easily the car cleans, how the gloss holds up over the first couple of winters, and whether there's genuine warranty support behind it.
A short, honest checklist beats any percentage:
- Choose an accredited installer working with a recognised coating system, not a mystery bottle.
- Ask what preparation is included and what aftercare is recommended.
- Assess results by ease of cleaning, gloss retention and warranty support, not by headline chemistry percentages.
To blow our own trumpet for a moment: we're one of the few who offer a choice of brands. We can do that because we're a larger outfit that sees a lot of cars, and we're not tied to a franchise or locked into a single badge. That lets us pick the product that suits you and your car, rather than defending whichever number happens to be printed on the only bottle we're allowed to sell.