Glass Defects
Glass Defects are unintentional parts of a given sheet of glass that alters the look or stability of said glass.
Seeds
Seed defects are very small pockets of gas trapped within the sheet. These small pockets of gas are benign and usually aren't on the very surface of the glass.
Folds
Folds are when the glass is rolled onto itself creating a distinct line where the glass meets itself. Folds can be very minor to severe, depending on the exact geometry of the fold dictates how it can affect the glass. Most folds will cause small issues when Scoring as the Scoring Tool will get stuck in them. While breaking the glass it's not uncommon for the Run to follow folds.
Bubbles
Bubbles are the bigger version of seeds.
Deep bubbles are trapped more near the center of the glass, they are larger than seeds through and often affect the flatness of the glass surface by creating lumps in the glass.
Blisters
Blisters are thin walled bubbles that will easily break from pressing on them or while working the glass.
Blisters are often elongated and smashed flat from rolling. These can be exceptionally annoying due to the thin wall causing the Scoring Tool to penetrate the blister surface becoming stuck. Some people will smash out the thin surface and continue to use the glass as is while others will avoid it entirely.
Inclusions
Inclusions are any type of foreign material trapped in the glass. Most commonly this is chunks of the furnace or parts of the Batch that did not melt properly.
Inclusions can be a major issue as the materials trapped in the glass will often cause the glass to spontaneously break/crack at the surface weakening the entire object due to differences in Coefficient of Expansion or other chemical incompatibilities. The trapped material will often cause bulging in the glass too. They are best to entirely avoid as they are unpredictable.
Bulges
Bulges are where the glass has deviated from being flat from an outside force. Often caused when the glass is grabbed too cold or something hits the semi-molten sheet after it's rolled. Budges can cause difficulties with working the glass as it's prevented from laying flat against the surface it's in contact with.
Crack
Cracks form for various reasons, internal stress from poor Annealing, incompatibility with another part of the glass, impacts to the glass where the crack does not fully propagate, other defects causing weak points for the glass to fail at which it normally would not.
Scratch
Scratches can be light or deep, light scratches could be buffed out with light abrasives while deep scratches are permanent and will not be removable. Scratches often come from hard objects or bits of glass rubbing against the surface during storage/transport.
| Defect Example | Defect Name | Defect Interference | Notes |
|---|---|---|---|
| Seeds | ★☆☆☆☆ | Essentially no effect on usability, some surface seeds may cause issues during scoring. | |
| Folds | ★★★☆☆ | Folds in the glass can cause | |