Capping the free edge is a manicure technique that draws the brush along the tip of the nail with each coat, sealing the edge of the polish film so it is less likely to lift and chip.
Also known as: capping the tip, sealing the free edge, capping nails, wrapping the tip
Capping the free edge means drawing the brush along the very tip of the nail after painting the surface. A thin band of polish wraps over the edge and seals the film where the nail ends. It is done with the base coat, each colour coat and the top coat.
Most chips start at the tip. The free edge takes the impact of typing, opening cans and knocks, and hot water makes the plate expand and loosen the film (Manucurist). An unsealed edge gives water and wear a way in. A capped edge closes it. Two thin colour coats with the free edge capped, then a top coat, is the standard long-wear protocol.
The technique: after the last stroke on the surface, turn the brush so the side of the bristles faces the tip. Wipe most of the polish off the brush first, then draw the brush across the edge from one corner to the other in one movement. The band should be thin. A thick cap pools under the tip and takes longer to dry.
Capping works on any nail length, including very short nails where the free edge is only a millimetre. On gel, the cap is cured with the rest of the coat. Reapplying top coat every 2 to 3 days, capped each time, extends wear further (Essie).