Hello I had a question about razors that are used for scrapping and their razor safety. I have noticed that most windows are never scratched, no matter how much the glass is scraped, however, in very rare events on what appears to be the same style of windows and glass, on a same job, one will develop extremely fine scratches clearly from the metal razor blade, they are extremely hard to see and usually can only be seen when the sun hits the window just right. I was curious as to the cause of this and the sure method of avoiding the issue. Thanks for any help and information on the subject.
Certain tempered glass windows scratch. But not all of them so it’s confusing. Just be careful and if the blade sounds funny on the glass just use steel wool instead to be safe. Watch out for bathroom windows and door window or any near a door. They are usually tempered
Glass scratches for a number of reasons. Glass fines from the manufacturing process (think sawdust only much, much smaller), it dislodges when scraped or even using 0000 steel wool, then dragging it across the glass scratches it. Worn or dirty razor blades will scratch glass. dirt and sand grit not washed or rinsed off the glass well then dragged with the squeegee will scratch glass. Someone wiping the glass with an abrasive cloth will scratch. Anytime something you cant see that gets dragged across the glass while cleaning will scratch glass. Heavy scratches that can be seen easily are just being negligent with the glass. Glass scratches. My glasses scratch when using the cloth supplied specifically for gleaning glasses.
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Sounds like you scraped a window with a titanium oxide coating (“self cleaning” or “low maintenance” glass). That’s how the damage will appear; you only see it under specific lighting and angle.
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This sounds about right, its definitely not like normal windows. Or possibly the tempered theory, but i read how glass is tempered and i couldn’t see any reason that would make it susceptible to scratching. These scratches aren’t a normal scratch like if you got a rock caught between the blade and the glass. Its definitely like something is coating the glass. Im just wondering how i can spot these windows. Ive also noticed its only on really high end houses and buildings. Really expensive places.
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Your squeegee will usually drag just a bit on coated glass. It’s not foolproof, but it is a clue. There also tends to be a particular sheen/reflectivity that you’ll learn to spot.
Certain brands you have to watch out for. Pretty much all windows from Andersen made in the last 20+ years have TiO2 coatings.
The coatings should only be on the exterior glass, since it’s meant to react with rainwater and sunlight to help breakdown dirt and organics to keep the glass cleaner, longer.
Also, tempered glass being more prone to scratching is a real thing. Research “fabrication debris”. There is debate over the science of why it happens, but everyone is in agreement that it does happen.
Thanks!
