Spots & Troubleshooting2 min read

Directional Coating Application Marks: Rotate the Sample During Inspection

Some marks become visible only when the viewing direction changes relative to the application path. Inspect a suspected directional pattern from more than one orientation before deciding that the finish is uniform or diagnosing its cause.

Updated · NANOLAB Knowledge

The key distinction

Keep the initial observation and application history together. A pattern aligned with wiping may be useful evidence, but alignment alone does not prove a particular error. Lighting, substrate texture and pre-existing marks can also influence what appears. The inspection should reproduce the pattern without adding new treatment that could erase the evidence.

Practical checks

  1. Photograph the panel with a documented orientation and light position.
  2. Repeat the inspection after changing the viewing direction while preserving the reference conditions.
  3. Compare the observations with the preparation and application record before selecting a corrective method.

Example

Illustrative example: a panel looks clear from one end of the bay but shows parallel marks from the other. A single release photograph would miss the concern. Recording both views gives technical support a more useful description than simply calling the coating cloudy.

Scope and limits

Do not immediately polish or apply another layer to a customer surface. The correct response depends on the product, cure stage and confirmed cause. Follow the supplier's instructions and preserve the original observations before making an irreversible correction.

Related guidance

Ask NANOLAB about the exact product and intended use. Use the current product documentation for formulation-specific instructions.

Spots & Troubleshooting1 min read

Coating Marks That Reappear After Drying

Water can temporarily change how a defect is seen. A mark disappearing when wet does not establish that it has been removed.