How can small hydrogen blisters on metal surfaces be easily detected?

Detecting small hydrogen blisters on metal surfaces can be effectively done by visually inspecting the area under bright light. This method allows the inspector to notice subtle surface variations that may indicate the presence of blisters. Bright lighting highlights imperfections, making it easier to spot these defects than relying on touch or other less definitive methods.

Using a magnifying glass might help with close examination, but it doesn't enhance the visibility of blisters as effectively under adequate lighting conditions. Applying pressure with a hammer could potentially damage the metal or the surrounding area, which is undesirable in an inspection context. Relying on touch to feel the surface may miss small or shallow blisters that are not easily discernible by touch and might not provide accurate information regarding the integrity of the material. Thus, a well-lit visual inspection stands out as the most effective approach for detecting small hydrogen blisters.