Which preparation is required before applying penetrant to a painted surface?

Which preparation is required before applying penetrant to a painted surface?

• A. Apply a primer
• B. Completely remove the paint
• C. Sand the surface
• D. Wipe with solvent

Answer: (B)

The main idea is that the penetrant must have direct access to any surface-breaking flaw. A coating like paint on the surface blocks the penetrant from entering the defect and can also trap contaminants that interfere with the process. Therefore, to properly apply penetrant and reveal flaws, the paint over the inspection area must be completely removed, exposing an clean substrate for penetrant application, development, and inspection. Simply priming, sanding, or wiping with solvent won’t ensure access to the substrate or remove the barrier the paint provides.

The main idea is that the penetrant must have direct access to any surface-breaking flaw. A coating like paint on the surface blocks the penetrant from entering the defect and can also trap contaminants that interfere with the process. Therefore, to properly apply penetrant and reveal flaws, the paint over the inspection area must be completely removed, exposing an clean substrate for penetrant application, development, and inspection. Simply priming, sanding, or wiping with solvent won’t ensure access to the substrate or remove the barrier the paint provides.