Pinhole & Holiday Detection Instruments
After a protective coating has been applied, it is important to ensure there are no defects or discontinuities present that expose the substrate beneath. Small areas of thin or missing coating, called 'pinholes' or 'holidays', can become foci for corrosion and drastically reduce the life of a protective coating system. A pinhole or holiday detector is a non-destructive instrument used for detecting discontinuities in a coating system including holidays, pinholes, and cracks. Other names include porosity detector, continuity tester, holiday tester, spark tester, and jeep meter.

DeFelsko offers two types of porosity/pinhole detectors: low voltage (wet sponge tester) and high voltage (spark tester). Low voltage detectors, like the PosiTest LPD, are typically used on paint systems less than 500 µm (20 mils) thick. High voltage holiday testers, like the PosiTest HHD operate at voltages up to 35,000 V and are typically used on coatings at least 200 µm (8 mils) thick.