Coating defect

Orange peel

A dimpled surface like the skin of an orange.

Orange peel: the surface as you see it, and a schematic cross-section.

Causes

Poor atomisation: too little pressure or paint too viscous.
Gun too far from the surface, or a thinner that evaporates too fast.
Paint that cannot flow out before it sets.

Prevention

Set pressure, tip and thinner as the data sheet says; keep the right distance.

How it is assessed

Usually cosmetic: compare with an accepted reference area. It matters where the specification sets appearance or gloss. If the film is near its minimum thickness, read the DFT in the dimples as well as on the peaks.

Telling it apart

Dry spray: Dry spray is rough and sandy to the touch, because the droplets dried before they joined. Orange peel is a joined, smooth-to-touch film with a dimpled surface.
Brush marks: Brush marks run in lines; orange peel is random dimples from the spray gun.
Runs and sags: Runs and sags are paint that flowed too much. Orange peel is paint that did not flow enough.

Repair

Where it must be corrected, abrade smooth and apply a further coat. The specification and the coating manufacturer have the final word on the repair procedure.

7 practice items in the members area mention orange peel (CIP 1: 3 · FROSIO written: 4).

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.