Transport protection can leave wax or another film on the surface intended for touch-up. Fresh paint may cover it without forming the required bond. The repair assessment needs to identify the residue and verify its removal under the coating system’s approved method. [1]
Resolve the surface in a sequence
Identify the transport material and the existing coating system.
Map the repair area and any residue beyond the visible damage.
Use the approved cleaning method and preserve its compatibility with the old film.
Verify the specified cleanliness and surface condition, including recesses or edges.
Apply and qualify the compatible repair system under its defined conditions.
This sequence is an evidence review, not a solvent prescription. An aggressive cleaner can affect the old coating or leave its own residue; a mild wipe can leave the original wax. Product-specific compatibility decides the method.
Check the boundary between old and new film
A repair needs adhesion to both the prepared substrate and any retained coating overlap. Record feathered or other specified transition geometry using the approved procedure. A visually smooth overlap does not establish intercoat compatibility.
Where wax identity is uncertain, retain that uncertainty and obtain the relevant material information or representative test. Do not assume every transparent oily film is the same transport protection.
Keep paint execution and supervision tied to the actual product and coated region; a finished appearance does not recover missing process evidence. [2]
Check the full contaminated repair boundary
Assume visible paint damage is 0.02 m², while validated residue mapping identifies 0.05 m² requiring treatment. Treating only the visible area leaves 0.03 m², or 60% of the identified contaminated boundary, unresolved. Select the compatible removal and repair method from actual product evidence before applying the next layer.
References
- ISO, ISO 12944-4:2017, Paints and varnishes — Corrosion protection of steel structures by protective paint systems — Part 4: Types of surface and surface preparation.
- ISO, ISO 12944-7:2017, Paints and varnishes — Corrosion protection of steel structures by protective paint systems — Part 7: Execution and supervision of paint work.