If you are planning to refinish a knife handle, understand some important points before you get started. Whether they are composed of wood, bone, fiberglass or metal, knife handles all share one characteristic: they are ill-suited for adhesion. You must condition the knife handle a particular way, based on its composition, or you will end up with flaking. In addition, you should choose a specific finish and employ the right application strategy, or you could end up with disappointing results.
Wash non-wood knife handles with trisodium phosphate cleanser, using a coarse brush. Rinse the knife handle with wet rags and dry it with towels. Skip this step if the handle is wooden.
Abrade bone, plastic and fiberglass knife handles to promote adhesion by sanding them with 180-grit sandpaper. Stop when the handle feels rough. Skip this step if the handle is metal or wooden.
Protect portions of the knife handle you do not want painted by covering them with painter's tape. Place the knife on a drop cloth.
Coat non-metallic knife handles with acrylic spray primer. Use metal etching spray primer on metallic knife handles. Maintain an 8-inch distance between the knife handle and the spray nozzle as you apply. Wait three hours for the primer to dry.
Coat the primed knife handle with oil-based spray enamel. Maintain an 8-inch distance between the knife handle and the spray nozzle as you apply. Wait three hours before handling the knife.
Sand wooden knife handles with 180-grit sandpaper. Stop when the finish appears dull.
Protect portions of the knife handle you do not want stained by covering them with painter's tape. Place the knife on a drop cloth.
Coat the knife handle with oil-based stain, using a 1- to 2-inch oil paintbrush. Wait four hours for the stain to dry.
Wash the brush with mineral spirits.
Coat the stained knife handle with varnish, using the clean paintbrush. Wait four hours before handling the knife.
Never paint unprimed knife handles, or the finish will flake. Don't use acrylic primer on metal knife handles, or the finish will chip. Don't use ordinary latex paint on a knife handles, or the finish will not remain durable.