Wet Sponge Pinhole Detection
Wet Sponge Technique: A low voltage is applied to a moist sponge. When the sponge moves over a coating flaw, liquid penetrates to the substrate and completes an electrical circuit, setting off the alarm. The wet sponge technique is suitable for measuring insulating coatings less than 500μm (20mils) on conductive substrates, and is ideal for powder coatings and other coatings where the user does not wish to damage the coating.