The solvent attacked the closure

Why all three shelves lean on glass

The polish shelf is 28 glass containers and nothing else; the treatment shelf is 60 glass; the remover shelf is 149 HDPE and 42 glass. Nail solvents attack polymers, and glass removes the wall from the argument.

Which leaves the liner

A liner that has softened or swollen is the commonest failure, and it shows as a cap that will not seal or a product that has lost solvent. Ask the supplier with your solvent named and its concentration given.

And the dropper bulb, on the treatment shelf

Forty of the 186 closures there are dropper assemblies, and a bulb is a flexible elastomer in contact with the formula. Bulbs harden, crack and stop drawing, and that is a slow failure a customer finds.

A thickened product is the same problem seen differently

If solvent leaves through a marginal closure, the lacquer or treatment thickens. The bottle looks fine and the product is wrong, which is why a weighed control sample is worth keeping.

Permeation is possible even in a good package

Small solvent molecules pass slowly through many polymer parts without any visible damage. Weighing a filled, sealed sample at intervals is the only cheap way to see it.

The brush and its stem count too

On a polish, the brush spends the whole product life submerged. Bristle and stem materials are part of the compatibility question and they are bought from whoever supplies the cap.

Test by waiting, upright and on the side

One of each, at one, three and six months, with a weighed control. Nothing on this page is visible on the day you fill, and all of it is visible by six months.

Weigh a control, it is the cheapest instrument here

A filled, sealed, labeled sample weighed every month tells you whether solvent is leaving, long before a customer tells you the product has thickened. One bottle and a kitchen scale.

References