Slicing Beer Bottles

I resumed my nocturnal bottle cutting activities recently. Bottle cutting is an obscure art. Not many people do it and there is not a lot of literature on how to do it.

Glass is a difficult material to cut properly. If the molecular structure of glass were crystalline, like metal, this would all be so much easier. But unfortunately, glass is an amorphous fluid. That means any attempt to cut glass may produce unpredictable results.¬† The cutting of glass itself may be best described as “controlled shattering”. Ideally, we want it to shatter in a straight line.

In order to cut glass, you must first etch a line with a glass etching hand-tool. Etching a line on a flat piece of glass with a straight-edge is easy enough but etching a straight, even line around the curved surface of a bottle is a totally different matter. That is why I built this custom-made device. There is no other device like it in the world!

This is how the bottle goes onto the device. Everything has to be measured and calibrated precisely, which is why you see an architect ruler in the photo. The bottle is slowly rotated with manual pressure applied. A cutting bit underneath etches a straight circle around the bottle. BTW, that happens to be a Heineken beer bottle.

The etched line must be heated with an open flame. I use a propane gas torch, which can be bought at Home Depot. Some people suggest using a candle flame but based on my own experience, I do not recommend it. A candle flame will leave a dark ash residue around your bottle. On the other hand, the propane flame burns cleanly so it won’t leave a residue. However, it’s much hotter than a candle flame so you have to be much more careful when heating the bottle. Apply too much heat and it can crack the bottle rather unceremoniously.

After the bottle is heated, you dunk it in a large container filled with cold water. When a material is heated, it expands. When it is cooled, it contracts. The idea is to use this expansion-contraction to apply shearing stress along the etched line around the bottle, thus leading to a controlled shattering.

So here are some sample of bottle that I have cut in the past. The cut edges are very sharp and jagged. It needs to be grounded down with an angle-grinder power tool.

Why cut bottles? I really don’t know how to describe it. As I mentioned before, it’s not easy. It takes skill, discipline, and lots of patience. But it is a very satisfying feeling to be able to perform a difficult task and do it well. On a practical note, I plan on using these cut bottles as containers for my impending project, which is making soy wax candles.

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2 Responses to “Slicing Beer Bottles”

  1. Great. Now I appear illiterate. You said right from the get-go that you were going to make candles with these things. :: smacks forehead :: This is what happens when you’re not slow and deliberate. I’m kind of a throw-it-all-out-there-and-reason-later type. No good. No good at all.

  2. That’s awesome. I think I want to try cutting a bottle just to say that I did it. I could see a lot of uses for a half bottle, and glass is nice in that it’s more solid than plastic.

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