How Much do You Know About Your Glass?

Glass today is pretty ubiquitous, to the extent that most of time we just look right though it without any thought. Yeah, that’s glass’s job, I get it, but it was a figure of speech. Anyway, there’s so much of it around us, and it facilitates so many things in our everyday lives, but how many of us have a clear idea of what it really is, how it’s made and where it came from?

So what is it, really? What’s in it? Typically, most basic glasses comprise various percentages of three crucial components: sand, potassium carbonate, and chalk or lime. What percentage those things come in really depends on what the glass is being used for, but, generally, it’s about 75% potassium carbonate, 24% sand, and 2% lime. Coincidentally, potassium carbonate is also used sometimes in soap, cocoa powder production, and as an ingredient in those delicious Chinese mooncakes with the fancy designs on them. Here’s the Wikipedia link, in case you need a rabbit to chase.

Most people would probably have guessed that, to actually make the glass, these three elements would be melted down into a molten-like form. And that’s exactly right. It can be heated any number of ways, so long as it reaches about 1000°-1600° Celsius. That’s hot. For those of you still clinging to standard measure like it really works (don’t worry, so am I), that’s upwards of 3000° Fahrenheit. Again, hot.

Once its molten, there are various ways to remove any impurities, including chemical additives and agitation. I’ll tell you, though, agitating a vat of viscous, sticky, 3000° incandescent sauce seems like a bogus plan to me.

With impurities gone, the burning goo can be drawn and rolled into giant sheets, for flat glass. Or, it can be pressed and blown, for hollow glass like light bulbs, fixtures, and fishbowls. Colored glass can be dies while in its molten stage, and it can also be printed or coated to achieve various colors. Mirrored glass is usually coated with a metallic, paint-like substance—mostly silver.

Considering the temperature at which this stuff is made, how long do you think it has to be cooled? Good question. It depends. The cooling time effects the final product’s brittleness and strength, but, generally, the slower the better. The strongest annealed glasses—those that aren’t subjected to further heat strengthening—can take up to several months before moving to other phases of production. I’m glad my pizza doesn’t take that long, because most of the time I barely have enough patience to wait for the cheese to cool. Man, I hate cheese blisters.

So how long has this whole process gone down? Well, a while. The approximate recipe we mentioned was probably drawn up by the Assyrians some time around 640 BCE, but we think glass has been produced as early as 8000 BCE, especially in Egypt, but maybe in Mesopotamia and Mycenae, China, and Northern Tyrol—a tiny little region of northern Italy and southern Austria.

Glass is obviously a lot different, and a lot more widespread today. But even as recently as the early Industrial Revolution glass was something of luxury. For example, you may have heard that in the late-17th century, the UK parliament imposed a window tax on its citizens across Scotland and England. Since glass was so expensive, having a lot of glazed windows was seen as an indication of prosperity, and thus the government felt added revenue could be extracted simply by adjusting taxes based on the number of windows a household enjoyed. The tax lasted until 1851—well into the Industrial Revolution—when it was repealed, as prosperity was no longer seen as a legitimate basis for increased taxation.

Now glass is everywhere. It’s easy and cheap to get, and we’re even coming up with new concoctions, like Gorilla Glass, by Corning, which uses alkali-aluminosilicate sheet glass stretched and flattened to be incredibly thin and almost unbreakable—almost. My old Galaxy 7, using the fourth generation of Gorilla Glass, didn’t quite make a shoulder-height tumble. Think we’ll have Gorilla Glass in our cars some day? Porsche does.

See you later.

A Tale of Clarity

We live in fervid times. Things are happening big, and they’re happening fast, so to keep our readers up to speed, the writers at Block & Olson’s blog tackle only the issues that really matter—the stories that carry weight, the ponderous problems convulsing the very core of what it means to have agency and independence in this age…the serious stuff. Today, we approach a controversy as old as glass itself and as contentious as a Florida primary; we’re talking about the best window cleaning stuff and the best ways to use it.

Weather it’s the mirror in your bathroom that seems to gather toothpaste freckles even though you brush your teeth three feet away, or the windshield in your car that turns into the Milky Way whenever you steer into the sun, you clean and clean and only really stop when you finally admit defeat. Well not any more. We’ll tell you everything you really need to know to get those glassy entities so clear you won’t even know they’re there. Except the mirror; you’ll know that’s there.

Let’s start with what not to use and what not to do with it when you’re not, well, using it. Don’t use Windex. Sorry SC Johnson, but there are a number of reasons why your glass cleaner can’t be found in a single reputable glass shop this side of the heliopause. To begin with, Windex (and cleaners like it) are too aqueous. Those types of cleaners—the ones in trigger spray bottles, usually—are too runny, and they don’t really do the cleaning work you need them to. The solution kind of splashes right where you spray it and drips away. You need something foamy, something that clings to the glass surface and stays there. Foamy cleaners mostly come in aerosol cans (don’t worry, the one we suggest is CFC free), but we’ll get to that part soon.

The runniness of the abovementioned cleaners also has another drawback: Streaks! They say they’re not streaky, but most of the trigger spray cleaners streak worse than a college freshman at the semi-finals. This could be in part the type of towel you’re using—more on that later—but it’s largely because there’s just too much liquid involved, and there isn’t anything to make it evaporate faster. They rely on you and your elbow grease to spread the liquid thin enough that it evaporates quickly and evenly. But how often does that happen when you’re sitting in your passenger seat twisted half upside-down, wiping the glass with the back of your hand to reach that part above your defrost? Aerosol type cleaners usually have some alcohol, or are entirely alcohol based, and those ones evaporate faster and more evenly, relying more on chemistry than manual labor to get the job done.

Another reason to stay away from Windex and its soggy friends is that most of them contain ammonia. Not all of them do, but a lot, and you can smell it from a mile away. But ammonia cleans stuff really good, you say. Yes, it does, because it’s caustic. What that means for your windows is that any coating or film on them will eventually be eaten away by the nitrogenous waste product, including the tint on your car’s windows and any performance or energy coating on the windows of your home. Maybe your car windows are as clear as day, but it’s a safe bet that if you have double-pane windows in your house, they’re coated with something to keep that nasty sun from hot-boxing your living space. So always check the ingredients of your glass cleaner, and always avoid ammonia.

What do we use at Block & Olson? We use Sprayway glass cleaner. They’ve been our go-to for at least 50 years. You can find it almost anywhere, but there are other products on the market just like it. Just make sure it’s aerosol.

The next critical thing is the towel you use. Forget about newspaper. For one, newspaper usually makes the things it touches dirtier. And who the holy internet actually buys a physical paper anymore? I call it reading the paper, but it’s all pixels these days. You need a thin, coarse, tight-knit paper towel. Think the kind of towels used in most public restrooms—more pliant and absorbent than computer paper, but not by much. Avoid the soft, fluffy stuff. Those kinds of things are great for sopping up milk on the kitchen counter, but they’ll leave a billion little fibers on the glass and probably a dent in your bank account too, at least compared to the rougher stuff. You can find the good stuff at a janitorial supply company that sells to the public, and at places like Home Depot, too.

Once you get the right equipment, the technique becomes markedly less important, but here’s some best practices to get you started:

  • Use the cleaners sparingly. You don’t need to slather it on; the more you spray, the more you have to wipe off, and that’s a recipe for streaks.
  • Instead of wadding up the paper towel, fold it nicely. Doing so will put more of it in contact with the glass. And it’s easier to get a dry spot if you need to, which relates to the next point.
  • Once your paper towel is saturated, it’s useless—just smearing dirty solution all over the glass. So flip and re-fold your towel frequently to make sure it’s pretty dry.
  • If it’s an especially icky job, smear the cleaner around with your hand before you wipe it up. Clean it like you’d clean yourself in the shower. Really dirty glass just won’t be a spray-on-wipe-off job; you’ll need some agitation, and who doesn’t like agitation?
  • When you’re wiping off the glass, use fast, circular motions. The faster you go the better, because you’d rather the towel deal with the dirty cleaner than the sun’s evaporative bent.

So there it is, the momentous scoop of the day from the writers of Block & Olson. We’ve been cleaning glass for 7 decades, we should know. And if whatever you’re cleaning just won’t clear up, it’s probably stained. At that point, there isn’t much to do but replace it. Fortunately, you know the guys to get that job done. Thanks for reading, and now go off and tackle the big problems of the day. The world is counting on you!