The concept of using a saw to cut glass is intriguing (it works for wood, doesn't it?), but there are a number of drawbacks. Glass saws are much more expensive to purchase than glasscutters and grinders. They are also very expensive to operate, with blades costing as much as a hundred dollars each. Because they require a steady flow of water to operate, they can be messy to operate and clean. Moreover, they cut much more slowly than cutting by hand.
So why use a glass saw? The answer is simple: they can cut things that are impossible to cut by hand. Once glass has been fused, for example, it's often too thick for a normal glasscutter to work. Some glass, fused and otherwise, also has a texture that makes it difficult to cut by hand. In these cases, only a glass saw has the strength and precision to get the difficult job done.
Glass saws are also capable of making intricate cuts that would be impossible to make by hand. Elaborate designs incorporating sharp inside curves and abrupt changes of direction can be cut with a saw. These pieces, which may be too flimsy to provide adequate strength when used in a work of stained glass, can easily be fused to a base sheet of glass, yielding a fused piece that is both unique and solid.
There are three main types of glass saws: band saws, ring saws, and wire saws. Band saws are far more prevalent and are available in a wide variety of sizes and configurations. Gryphon and Diamond Tech are two of the best known manufacturers. Band saws use a thin blade with diamonds on one edge. You cut the glass by pushing it into the blade, which is flexible enough to permit maneuvering the glass to cut intricate patterns. The blade requires water at all times, so that the glass doesn't overheat and crack.
Ring saws, which also require water at all times, use a round, diamond-coated blade that's capable of cutting in any direction, rather than the single direction of the band saw. They can cut slightly tighter curves than band saws. The Gemini Saw Company makes the best-selling ring saw, the Taurus II.2 Ring Saw. The major drawback of the ring saw is that the blade is relatively thick; as a result, it removes more glass than the typical band saw.
A third type of saw, the wire saw, has recently become available from Gryphon. This saw, which has the ability to make inside cuts without a lead-in, uses relatively inexpensive (but short-lived) diamond blades that can cut in any direction. It is not as fast as similar band saws and, like the other kinds of saws, the wire saw requires constant bathing with water to keep the glass from overheating and cracking.
If you do purchase a glass saw, realize that it will supplement, not replace your manual glasscutter and pliers. While saws can make intricate cuts and can safely cut through thick or heavily textured glass, a manual glasscutter is still the best tool for straight lines or quick cutting.