Tips on Choosing and Using Filler Compounds
Filler compounds are invaluable for mending cracks and filling holes in wood or metal surfaces. Several kinds of fillers are available, and the choice depends on the surface you're working with.
Shellac sticks are thin strips of wax melted with a soldering iron to fill in cracks and holes in wood. The sticks come in different shades of brown to match various woods. After filling in a hole with a shellac stick, gently scrape the top of the hole with a chisel to remove excess wax. After the wax has cooled, smooth the surface of the wood with sandpaper.
Filling holes in stained wood is often difficult because it's hard to match the color of the wood. To match the wood more closely, mix putty with a few drops of wood stain before applying it to the hole.
Water putty is the substance of choice for filling cracks in wood. Water putty lasts longer than regular putty because it never dries out. It comes in powder form and should be mixed with water in a 3:1 ratio (3 parts powder to 1 part water).