What is the best way to check for a pinhole leak?

Using a piece of wood or cardboard to check for a pinhole leak is effective because it allows for a gentle and careful approach to identifying potential leak points without causing any additional damage to the surface or the material being inspected. This method helps to detect small leaks by feeling for moisture or seeing if the material yields in certain areas, while also providing a clear surface area to check against.

In contrast, using your hand or arm may not provide the same level of protection or may not allow you to sense the presence of a pinhole leak accurately, especially if the leak is small and doesn’t create enough moisture immediately accessible to the skin. Examining the hose is important and could reveal visible signs of wear or damage, but it may not directly indicate the presence of a pinhole leak, especially if it's located in a less accessible area. The use of wood or cardboard is specifically attentive to delicately uncovering leaks while minimizing disturbance, making it the best choice in this scenario.