Coating defect

Holidays and misses

Bare or thinly coated spots: large misses are plain to see, while pinholes and small holidays often are not.

Holidays and misses: the surface as you see it, and a schematic cross-section.

Causes

Application error, mostly on complex shapes with poor access.
Air bubbles from overmixing that burst and do not close.
Sags or curtains that leave thin areas above them.

Prevention

Stripe coat edges, welds and corners.
Inspect between coats, and apply a brushed coat at right angles to the previous one.

How it is assessed

Visual inspection, then holiday testing where specified: low-voltage wet sponge for thin films, high-voltage spark testing for thick ones. Set the spark test voltage from the measured DFT, as NACE SP0188 and ASTM D5162 describe, and test only a cured film.

Telling it apart

Pinholes: Pinholes are a kind of holiday: tiny holes through the film, often in groups. A miss is a larger bare or thin area.
Crawling and cissing: Crawling also leaves bare spots, but with paint gathered round their edges.

Repair

Mark, prepare and repair each holiday, then test the repair again. The specification and the coating manufacturer have the final word on the repair procedure.

100 practice items in the members area mention holidays and misses (CIP 1: 41 · CIP 2: 42 · FROSIO written: 17).

Try it in an exam-style question. The free readiness check shows the question style, explains every answer and gives you a dated study plan.

Take the free readiness check See the tracks

About this page

Written from coating practice and the published rating standards, in our own words; the drawing is schematic. Checked on 2026-10-14; errors go in the corrections log. CoatMentor is an independent study aid. It is not affiliated with ISO, AMPP, SSPC, NACE International, ASTM or FROSIO.