Glue Chipped Glass

This intriguing technique uses hide glue to chip off flakes of glass from a panel leaving a fern-like chipped pattern. It has been used occasionally in signs and in stained glass windows since the early 20th century . It has had a minor resurgence over the last couple of decades.

Glue chipped glass can be water gilded. Care will be required as it is easily rubbed off the high points. It will tend to have more breaks and require much more patching than usual. It may require an additional layer of gold for full coverage.

Oil gilding is easier although it doesn't produce the same beautiful reflections as a bright gild. It can also be silvered or chemically gilded using the related method known as angel gilding.

The basic method to produce it is:

• Sand blast or abrade the area of the glass to be chipped. This provides some tooth for the glue. The area can be masked with an appropriate masking film if a specific pattern is desired
  
  
• Spread glue to the required thickness on these etched areas. If a pattern is planned, allow the glue only on these areas.
  This can be done by painting asphaltum (bituminous paint) on the negative area which acts as a resistive to the glue. Cutting the extraneous glue away from the edge is also sometimes used.
  
  
• Keep the glass panel in a warm place or in the sun and the chipping happens as the glue dries over the next half a day. The glue shrinks as it loses moisture content and chips off fragments of glass.
  
  
• Clean the glass. Asphaltum is cleaned off with Mineral turpentine.
  Be careful of the fine sharp slivers of glass, some of which will be embedded in the dried glue. Keep away from animals as they may try to eat it.
  
  
• Gild or paint as required

The recommended hide glue is 5X mixed at a ratio of 1:1 dry glue to water by volume. By weight it is 1:2, glue to water. The glue is made in the same manner you would use for genuine glue size for gesso or woodwork. Heat (don't boil) in a double boiler or microwave, then spread to a thickness of 1-2mm. A thicker layer will create a larger chip pattern. Approximately 400gm glue/800ml water per square metre.