What points determine a pipes overall quality?
There are several main points to look for when determining the quality of glass: 1. No cracks! When buying a piece of glass, check it carefully for cracks. Hold it up to the light, and rotate slowly while meticulously examining for cracks. Any pipe that has a crack you can consider virtually worthless, as it will almost surely break there at some point in the not-so-distant future. 2. Thickness consistency. While thicker glass is stronger, and generally better, it is of more importance that glass be evenly thick (NOT overly thick on one side, and thin on the other). To understand why this is so important, you have to understand a little bit about how glass stresses as it cools. You can imagine that glass, like other materials, expands whenheated, and contracts when cooled. When two areas of the same piece of glass have different thicknesses, a stress occurs between the areas, as they cool with different contraction rates. (This is because the thicker part retains more heat, thus contra
