Chipping glue is a high-quality animal glue used primarily in the process of creating glue chip glass, an attractive effect on glass that leaves a frost-like or fern-like pattern that is particularly popular with sign-writers.
The process involves first sandblasting clear float glass to give it tooth for the glue to adhere to and then heating and applying the glue thickly to the areas you would like chipped. As the glue tries it contracts, pulling flakes of glass from the surface in a random fashion.
Chipped glass is very popular for backgrounds in windows and cabinets where it creates a unique, elegant effect in every piece that is finished using the technique. Glass that has been chipped can also be gilded, further enhancing an already appealing finish.