Gold leaf will transform almost any object into an ornate, lustrous work of art. In a process known as gilding, thin layers of gold are adhered to a surface. The gold can be burnished to create different surface effects or can be sealed with varnish. There are several types of adhesives available for adhering gold leaf. Each adhesive has its own characteristics and as you experiment with different types you will develop your own preference.
Rabbit Skin Glue
Rabbit skin glue is a centuries-old adhesive traditionally used by painters to seal their canvases. Made with collagen from the hides of rabbits, rabbit skin glue comes in powdered or liquid form. Gilders typically use the powdered form, which is made into glue by combining it with water and alcohol, and then heating the combination in a double boiler. When cooled, it takes on a gel-like consistency. It is also possible to combine rabbit skin glue with gesso to prime a surface for the application of gold leaf.
Gelatin glue is similar to rabbit skin glue and is made from the collagen of animal skins, bones and hooves. Gelatin glue is sold in granule, capsule or sheet form, and is also heated in a double grill. Gelatin glue, as well as rabbit skin glue, mixed with burnishing clay will create a black or an earth-toned base. Once gilded and burnished, the rich colour of the clay will trickle through the semitranslucent gold layer.
Egg White Glue
Used in medieval times for applying gold leaf, egg white glue is a homemade glue made from eggs that have had their yolks discarded. There are various recipes for egg white glue but, typically, egg white is mixed with water and left to stand overnight. The foam that forms is then scooped away and the liquid is strained.
Oil-based adhesive is made with solvents and is a suitable choice for outdoor projects that are also being sealed. Oil-based adhesive is strong, but it is also vaporous--and best applied in a well-ventilated environment. White spirit added to the adhesive will thin the consistency, increase the flow rate and make your supply last longer. White spirit is also used to clean brushes used with oil-based adhesive.
Although it may not have the strength of oil-based adhesive, water-based adhesive is a less-vaporous and dries faster. It is sufficient for indoor projects, however it is not possible to burnish gold leaf applied with water-based adhesive the same way that you can burnish gold leaf applied with rabbit skin or gelatin glue. Brushes used with water-based adhesive are cleaned with soap and water.