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

Which condition would NOT be detrimental to a liquid penetrant test?

1. Wet surface

2. Rough surface

3. Dry surface

4. Oily surface

The correct answer is: Dry surface

A dry surface is indeed the condition that would not negatively impact a liquid penetrant test. In liquid penetrant testing, the goal is to apply a penetrant to a non-porous material to identify surface-breaking defects. For this process to be effective, the surface must be clean and properly prepared to allow the penetrant to enter any flaws. A dry surface ensures that there is no moisture that could interfere with the penetrant's ability to adhere and penetrate into the defects. In contrast, a wet surface can dilute or wash away the penetrant, compromising the test results. A rough surface may trap penetrant in an unpredictable manner and can lead to uneven readings. An oily surface presents a barrier to the penetrant, preventing it from adequately wetting the surface and entering any defects. Thus, a dry surface is favorable as it allows for optimal penetration and detection of flaws.