Fire Break Glass

Make beautiful art of glass mosaic tiles, it's easy! Let me show you how.

You wonder what glass actually is? Do we cut it or break it (is there a difference)? Why and how to mark a line allow us to control the way glass breaks? To understand why we cut the glass as we do, we must first understand a bit about glass itself.

There are two types of solids: amorphous and crystalline. (Huh? Amorphous? Was not he a character in the movie series The Matrix? No, it was Morpheus.) As you'll learn in my eBook in the chapter on Tessera Types, glass is a solid amorphous (chapter explains what glass is to help the artist of the mosaic to better understand how the cuts and breaks, and help reduce wasted glass). An amorphous solid, like glass and plastic, has molecules arranged randomly in no particular model. On the contrary, a crystalline solid has molecules arranged in fixed patterns, sometimes called lattices. Most solids are crystalline, such as metal, glass, and diamonds.

Glass may break in a controlled manner (for example, along the line score) because it was not a specific molecular structure. For example, a diamond breaks cleanly along its molecular structure fixed or cleavage (most often understood as "grain"). If you do not properly align your tool to break along the grain, the diamond can shatter. However, because the glass has not a grain, you can break in any direction without breaking. The question is how we get to break the way we want?

Depending on the tools used, the glass may break either exceed its tensile strength or cutting overcome its resistance to compression or shear. To control the fracture, we must define which exceed the tensile, compression, or shear strength to cause a fracture controlled. We do this by putting the glass break when you want by applying a tensile or properly aligning the cut when you want to cut it by applying a compressive force or shear. For example, the tensile strength of glass, along with a quick score line is less than anywhere else on the glass, it tends to break cleanly along that line (eg, the pause that follows the path of least resistance).

When separation occurs due to tensile stress, the separation is called a "rupture". When a separation occurs because the shear stress or compressive stress, the separation is called a "cut".

When you use a scoring tool and running pliers on the window, you apply the tensile stress to break the glass. When using cutting wheels with two wheels aligned (or other tool with cutting edges aligned, such as forceps), you apply a compressive force to cut glass. When using cutting wheels with two wheels skewed (eg because you dropped the tool and jaws leaned out of the alignment) is applied shear stress to cut glass. (The best known example of a misaligned cutting tool cutting edges is a pair of scissors where the two cutting edges are side by side instead of alignment.)

Remember, making mosaic art is easy. You can do it. Yes you can!