# Dry spray

Source: https://coatmentor.com/defects/dry-spray/ · Updated 2026-10-14

A rough, sandy, matt surface. The droplets dried before they reached the surface and did not flow together.

*Figure: Dry spray: the surface as you see it, and a schematic cross-section.*

## Causes

- Gun too far from the surface, or wind and high air temperature.
- Very hot steel: the solvent flashes off before the film flows.
- A thinner that evaporates too fast.

## Prevention

- Keep the gun distance and use the thinner for the conditions.
- Respect the maximum surface temperature. Work in cooler hours or shade the steel.

## How it is assessed

Visual and by touch. The film is porous, so a coat applied over it may fail. Check the DFT: the porous layer can give a reading that looks right while the film protects poorly.

## Telling it apart

- **[Overspray](https://coatmentor.com/defects/overspray/):** Overspray is dry spray that landed outside the area being sprayed, on nearby steel.
- **[Orange peel](https://coatmentor.com/defects/orange-peel/):** Orange peel is a smooth, joined film with dimples. Dry spray feels like sandpaper.

## Repair

Abrade or sand off the loose, rough layer before the next coat. The specification and the coating manufacturer have the final word on the repair procedure.

**32** practice items in the members area mention dry spray (CIP 1: 13 · CIP 2: 4 · FROSIO written: 15).

## Related

- **Concepts:** [Protective coating types](https://coatmentor.com/learn/coating-types/)
- **Standards:** [ISO 12944](https://coatmentor.com/standards/iso-12944/)

## 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](https://coatmentor.com/method/). CoatMentor is an independent study aid. It is not affiliated with ISO, AMPP, SSPC, NACE International, ASTM or FROSIO.