Wooden handrails are finished with a varnish topcoat that protects them from abrasion and moisture. This glossy sealant also prevents primer and paint adhesion. If you apply a new finish directly over a varnished handrail, peeling will occur. You must condition the handrail, using the appropriate steps, or you will have no paint adhesion. This also can help you avoid mistakes before damaging the handrail. You also must apply a durable finish, or brush strokes will appear in the finish coat.
Sand along with the wood grain of the varnished handrail until the existing finish appears dull.
Wipe sawdust from the handrail using sticky tack cloths.
Apply painter's tape to the support balusters and other areas that will remain unfinished. Cover the area underneath the handrail with dust sheets.
Coat the handrail with latex primer. Brush along with the wood grain using a polyester paintbrush. Wait two hours for the handrail to dry.
Wash the brush with water.
Coat the primed handrail with gloss latex paint or acrylic enamel, using a clean brush. Wait two hours for the handrail to dry.
Treat stained handrails with an oil-based primer.
If you sand against the grain of the varnished handrail, splintering might occur. Do not paint unprimed handrails or the paint will peel. Do not prime unsanded varnished handrails or flaking will result. Do not prime or paint handrails using a nylon brush. Brush strokes will show up in the finish.