The multi-voltage pinhole detector, which uses the wet sponge principle to detect through pinholes, cracks and damaged areas in protective coatings up to a maximum thickness of 500 microns. Pinhole Detectors or wet sponge tester detects pinholes, voids, thin spots, foreign inclusions, or contamination in coatings film. Dielectric srenth of film also refered as holiday detection.

A low voltage holiday detector / wet sponge tester operation is by the application of a wet sponge to the coating. The wetting agent penetrates any pinhole and makes a conductive path through to the substrate, the pin hole detector automatically detects this conductive path and sounds an audible alarm and also gives a visual warning by a flashing red indicator that a pinhole fault has been detected. The flaw can now be marked for repair and further testing resumed. Coating on metals prevents to corrode unless a protective coating is applied. Pinholes based on wet sponge method generally caused by air entrapment that is then released from the surface, or by the entrapment of particulates (dust, sand, etc.), which do not stay in place. High voltage holiday detector is used for testing coatings above 500µm and low voltage holiday detector (Pinhole Detector ) is used below 500µm of coating on metallc substrates.

The Pin-hole multi voltage detectors or wet sponge tester has selectable test low voltages of 9 Volt / 67.5 Volt and 90 Volt which comply with ASTM specifications. Generally 9V will test up to 100 micron, 67.5 Volts will test over 100 to 300 microns and 90 Volt will test up to 500 micron. This wet sponge technique is recommended for paint, epoxy, powder, polymer coatings, plastic, teflon, rubber and non-conductive thin coating to access the quality of coatings without damage to occur to the coating on metallic substrates. Pin hole detectors can be used on painted vessels, pipes and pipelines of curved surfaces, cars, which are coated to withstand a highly corrosive environment s. When the coating thickness exceeds 500 microns, high voltage holiday detectors are recommended. Pinhole / Porosity Standards ASTM G62-A, ASTM G6, ASTM D 4787, ASTM D-5162, AS3894.2, BS 7793-2, BS EN ISO 8289 A (Wet Sponge Testing), NACE RPO274-98, NACE RP 0188 and AS1580.485.1 describe the use of pinhole detection and holiday detector.

The pin hole detector / wet sponge tester is supplied ready to use in a carrying case complete with handle / sponge, earth cable and battery fitted.