Skillfully cutting and breaking off glass seems difficult to comprehend only at first glance. Having in your hands a good, and most importantly – suitable glass cutter along with basic theoretical skills, you can easily cope with the task, although it is very likely that not on the first try.
Types of glass cutters
There are two types of manual glass cutters. Roller skates are most popular because of their cheapness and ease of use. A sharply sharpened roller made of silicon carbide, tungsten carbide or a special steel alloy, fixed in a mandrel with a small handle, pushes a sufficiently deep and wide groove in the glass, along which the glass sheet is very easy to break with the formation of a direct chip.
Roller glass cutters have a short service life and are often unpredictable: a fragile roller can crumble with excessive force, but it must be high enough. On the other hand, such a glass cutter is very easy to use: even a beginner will master this tool after a few workouts..
In diamond glass cutters, the cutting organ is represented by a crystal of artificial or real, but illiquid diamond. The crystal is firmly soldered to a massive block, on the reverse side of which a handle is screwed. Diamond glass cutter leaves behind a very thin (sometimes almost indistinguishable), but perfectly even furrow with practically no chips at the edges.
The fracture after a diamond glass cutter is much cleaner, but the tool requires a certain skill. This tool is exclusively professional grade, it is very durable (natural diamond can be used for decades) and each piece is unique in its own way. More indicatively, a diamond tool is a straight razor, while a roller tool is a disposable razor..
For precise cutting of glass, it does not need to be sawed through its entire thickness. This material is quite brittle, and its hardness is high as long as the structure is homogeneous. But it is enough to make a small incision, and the glass will burst exactly on it with the slightest effort. Making such an incision is called marking..
The mandrel of the glass cutter has a beveled edge. If you attach one of the inclined edges to the glass, then the conditional line of its surface will pass exactly a few micrometers above the edge of the cutting roller. In other words, it is enough to simply press the glass cutter with a mandrel against the glass to obtain a cut of sufficient depth without having eye contact with the working body itself..
This is more difficult in diamond glass cutters. The cutting crystal in them is hidden behind an even more massive head, and although the direction of the cut is quite easy to control, the real position of the diamond is hidden from view. In addition, any diamond has only one or two cutting edges, they need to be found, as they say, by touch. At the same time, the markings are applied without effort at all, the glass characteristically sings loudly under the diamond.
The scoring line should be a shallow but even scratch. Roller glass cutters do not cut the groove, but push it, which is why gentle chips are formed along the edges. Because of this, the fracture line may later “wiggle” or a rough chip with many sharp edges may form. Marking is done in just one stroke – this partly expresses the difficulty of cutting glass.
In practice, any cutting precision may be required. For example, glass for wooden windows can have a deviation of 1–2 mm, and the quality of the ends is not particularly important. In this case, the glass cutter can be guided by hand along the line drawn by the glass recorder. To avoid drawing a line every time, you can display it on the cutting table or put paper tape under the glass.
To cut double-glazed windows, it is necessary to guide the glass cutter along the attached strip. The result will be a straight line that, when broken, forms a smooth edge without chipping or sharp areas.
There are also special cases when glass cutting must be perfectly accurate and the cut must be perfectly processed. In this case, a cutting bar is used, on which a support carriage with a glass cutter is fixed. Only in this case will the cut quality be guaranteed to be high. Processing of the ends can be carried out with special stripping machines, removing a thin bevel, as on glass of aquariums and mirrors.
There is also artistic glass cutting, usually done with a diamond glass cutter. Cutting a curved figure out of glass is quite difficult, for this you need, firstly, to apply accurate markings without double scratches, and secondly, very carefully tap along the entire cutting line with a mandrel or glass cutter head until a through crack forms. If the part is cut in the center of the sheet, the edges will have to be divided into several thin pieces. For shape cutting, exotic methods such as spot overheating with a soldering iron or cutting with a pendulum saw are also used, in any case, the cut is almost never perfect and requires subsequent processing.
The aforementioned tapping of the notch is relevant not only for curly cutting. This is a fairly common technique to increase the likelihood of successful breakage and quality edging. Strikes should be short and precise, but not necessarily strong.
As for directly breaking glass, this can be done in completely different ways. The first and the simplest one is to put the glass on the edge of the table and press on the protruding part of it. If the crack on the glass is even enough, the glass will safely break exactly according to the markings, but this method is not suitable for long cuts.
It is interesting that glass is not only hard and brittle, but also quite elastic in structure. It can also bend, so if you sharply raise it by one of the edges parallel to the cutting line, and then sharply raise and lower the blade, as if creating a wave, the overload will evenly fall on the damaged area and the glass will crack along a straight line.
There is another way: a low triangular glazing bead is placed just under the furrow on the glass. If you put a cut glass on it, it will crack even under its own weight. Even if a similar load is applied in only one place, the crack will expand evenly along its entire length..
Why jagged faults are produced
When working with glass, it is very important to have a firm hand, at the same time, when cutting, it is unforgivable to be rude in handling the material. The best way to master the art of cutting is to understand how the mechanics of a glass cutter work by first practicing on old or unwanted glass.
Remember that not all glass lends itself to hand cutting and breaking. Tempered glass, for example, crumbles into many small fragments at the slightest structural damage. There are also intermediate options: glasses of poor quality or with a broken structure will give their own pattern of cracks, regardless of the applied markings.
If the break line goes to the side, pay attention to the cutting technique and the condition of the glass cutter. Perhaps you are not applying firm enough pressure, or perhaps the chipped edge of the cutter wheel is to blame, leaving small bridges..