Bubbles in nail polish: why they appear and how to stop them

Bubbles appear in the last minute of a manicure and ruin the first. They show as tiny pits across the surface, or as a few larger domes near the cuticle, and a top coat makes them more visible. The polish is rarely at fault. Air got into the film, and the surface set before the air could leave.

Each way air gets in has its own fix. A shaken bottle, a thick coat, a warm room, an oily nail and a bottle past its best all bubble for different reasons, and the routine that prevents all five takes no longer than the one that causes them.

What causes bubbles in nail polish?

A bubble is a pocket of air or solvent vapour trapped under a skin of polish that has already set. Lacquer dries as its solvents evaporate from the bottom of the film up (Personal Care Magazine). If the surface hardens first, anything still rising through the wet film below it, air from the bottle or vapour from the solvent, is caught and leaves a pit or a dome.

NailKnowledge lists the causes as thick coats, a shaken bottle, cold thickened polish, high temperature and humidity, air worked in by heavy brush strokes, surfaces that dry too fast under fans or quick-dry products, and old polish whose solvents have evaporated (NailKnowledge). Oily nails are a further cause given by manicurists (Makeup.com).

Does shaking nail polish cause bubbles?

Yes. Shaking mixes air into the lacquer as thousands of tiny bubbles, and they go onto the nail with the brush. The polish looks fine in the bottle because the bubbles are too small to see, then the film sets around them. Manicurists quoted by Makeup.com give the same advice: do not shake, roll the bottle gently between the palms, and let it stand before painting (Makeup.com).

Rolling does what shaking is meant to do. Pigments and pearl that have settled at the bottom of the bottle mix back in as the bottle turns, and no air is beaten in. Thirty seconds of rolling, then a minute standing upright, is enough for a crème. Glitters and magnetic polishes with heavy particles may need a minute of rolling.

If a bottle has been shaken, put it down for ten minutes with the cap on. The bubbles rise and break at the surface on their own, and the polish is ready to use.

Why do thick coats bubble?

A thick coat forms a dry skin on top while the polish under it is still wet. Solvent keeps evaporating from the wet layer, and because the skin is already set the vapour has nowhere to go. It gathers into bubbles under the surface, and the pits appear as the coat finishes drying. NailKnowledge puts it plainly: thick layers of polish trap air and slow down the drying process underneath (NailKnowledge).

Thin coats let the solvent out before a skin forms. The standard routine of two thin colour coats with 1 to 2 minutes between them is the one Manucurist and Essie recommend for wear, and it is also the one that prevents bubbles (Manucurist). Load the brush once, wipe one side on the bottle neck, and let the bead run out as the brush reaches the tip.

The top coat is the coat most often applied too thick, because a generous bead levels better. A medium bead is enough. If the top coat bubbles and the colour did not, the top coat went on too heavy or went on before the colour was touch-dry.

How do heat and humidity cause bubbles?

Heat speeds evaporation at the surface, so the skin forms before the film below it has released its solvent. Humidity adds water vapour to the air, and solvents evaporate more slowly into humid air, which keeps the lower film wet for longer. Together they produce the pitting that appears a few minutes after painting on a warm, damp day (NailKnowledge).

The same thing happens indoors with a hairdryer on hot, a fan pointed at the hands, a radiator or direct sunlight. A cool, dry room is the correct setting for painting nails. To speed drying without bubbles, use cool air only, or a dip in cold water after the surface has set for a minute or two (Nagelstudios.nl).

Cold polish bubbles for a different reason. A bottle kept in a cold room thickens, and thick polish drags, needs more strokes and traps more air. Warm it in the hands for a few minutes, never in hot water, and it spreads again.

Do oily nails and old polish cause bubbles?

Oil on the nail plate stops the polish wetting the surface evenly. The film pulls back from the oily spots, most often near the cuticle where sebum and hand cream collect, and the gaps and the small domes around them read as bubbles. A wipe with nail polish remover or rubbing alcohol before the base coat removes the oil, with attention to the corners of the plate (Essie).

Old polish bubbles because its solvents have evaporated through the cap over months of use. What is left is thicker, drags on the brush and traps air in every coat. Makeup.com's manicurists put bottles older than about a year and a half at the top of the list for bubbling (Makeup.com).

The fix is nail polish thinner, a solvent blend that replaces what has evaporated. Add three or four drops, roll, and repeat if needed. Remover is the wrong product: it contains acetone or ethyl acetate with oils and water, and it breaks the film so the polish never dries properly again. Store bottles upright, closed tightly, in a cool and dark place to slow the loss.

How do you fix bubbles that are already there?

Small pitting in a dry manicure can be smoothed. Wait until the polish is fully dry, which takes several hours for regular polish (Nagelstudios.nl). Pass a fine buffer very lightly over the surface to flatten the pits, wipe the dust away, and apply one thin coat of top coat. A thick self-levelling top coat fills fine texture best.

Larger domes and bubbles near the cuticle need a repaint of that nail. Remove the polish, wipe the nail with remover to degrease it, and paint again with thin coats. Manicurists quoted by Makeup.com give the same verdict: there is no easy repair for a heavily bubbled nail, and starting over is the fastest route (Makeup.com).

Bubbles in every coat on every nail point to the bottle, not the technique. Roll it, rest it, thin it if it is old, and if it still bubbles, retire it.

The bubble-free routine, step by step

You will need: nail polish remover or rubbing alcohol, a base coat, your colour, a top coat, nail polish thinner for any bottle that has thickened, and a cool, dry place to paint.

1. Bring the polish to room temperature. Warm a cold bottle in the hands for a few minutes.
2. Roll each bottle between the palms for 30 seconds, then stand it upright for a minute. Do not shake.
3. Wipe each nail with remover or alcohol, including the corners, and let it flash off.
4. Apply one thin base coat with a light touch, three strokes, and cap the free edge. Wait 1 to 2 minutes.
5. Apply two thin colour coats, 1 to 2 minutes apart. Load the brush once per nail and let the bead flow without pressing it.
6. Wait until the colour is touch-dry. Apply one medium coat of top coat and cap the edge.
7. Keep the hands still and away from heat, fans and sunlight for 5 minutes, then keep them out of hot water for the evening.