Liquid Penetrant Testing Level 1 (PT-1) Practice Exam

When conducting a water washable liquid penetrant test, when is wet developer applied?

1. Before the penetrant

2. After removal of the penetrant

3. During the penetrant application

4. Simultaneously with the penetrant

The correct answer is: After removal of the penetrant

In a water washable liquid penetrant testing process, the wet developer is applied after the removal of the penetrant. The role of the developer is to enhance the visibility of any defects that may have been highlighted by the penetrant. When conducting the test, the penetrant is first applied to the surface being inspected, allowing it to seep into any surface defects. Following this, the excess penetrant is removed, usually using water, which is a critical step to ensure that only penetrant trapped in defects remains on the surface. Once this excess penetrant has been adequately removed, the wet developer is then applied. The developer works by drawing out the remaining penetrant from the defect into the developer layer, which creates a contrast against the background surface. This process is crucial as it makes any potential defects more visible during inspection. Therefore, the correct timing for applying the wet developer is indeed after the removal of the penetrant, as it ensures that the inspection can be carried out effectively with enhanced visibility of possible flaws.