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Low voltage Pinhole Detector for Metal and Concrete Substrates. Detects holidays, pinholes and other discontinuities in coatings on metal and concrete substrates.
DeFelsko's PosiTest LPD is the smartest and most ergonomic pinhole detector available, it weighs less than other products and offer unique features that ensure correct operation and reliable performance. These features include GroundSense™ to ensure the electronic circuit is correctly connected and calibrated voltage outputs.
A pinhole detector is an electronic test system for detecting discontinuities in a coating system including pinholes, cracks and thin spots. Other names include porosity detector, continuity tester, sponge tester and holiday detector.
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. They can be invisible to the naked eye.
Porosity detectors are often used in applications where corrosion is difficult to monitor, or in aggressive service environments where performance of the protective coating is critical.
There are two types of pinhole detectors, low voltage (wet sponge) and high voltage (spark tester). Low voltage detectors, like the PosiTest LPD, are typically used on coating systems less than 500 µm thick.
A low-voltage pinhole test is performed by moving a moistened, electrified sponge over a non-conductive coating applied to a conductive substrate. The instrument is 'grounded' or 'earthed' to the conductive substrate, typically by clamping onto an uncoated area.
When the coating is continuous and no defects are present, electronic current is unable to pass from the sponge to the substrate through the non-conductive coating. But when the electrified sponge encounters a flaw in the coating, electricity is able to flow into the substrate and travel back to the instrument through the ground wire, completing the circuit and setting off the audible and visible alarms.
Testing over Concrete
Concrete is still slightly conductive, and can carry enough current to allow low-voltage pinhole detectors to function, so concrete is considered a 'conductive' substrate for low voltage pinhole testing only. When measuring coating thickness with tools such as the Positector 6000, concrete is not considered a 'conductive' substrate, as it is much less conductive than metal.
The challenge when conducting low-voltage pinhole testing on concrete is to ensure the instrument is properly grounded. If there is exposed rebar or metal protruding from the concrete, this is the easiest solution. An alternative is to drive a metal rod (or piece of rebar) into the ground nearby the concrete to at least the depth of the slab, relying on the earth to conduct the electric current between the rod and the slab.
The PosiTest LPD can be supplied as a Basic or Complete kit, the contents of which are listed below. There is also a range of spares and calibration tools available:
PosiTest LPD Basic
Includes everything needed for detecting pinholes using a rectangular sponge
Basic Kit comes complete with PosiTest LPD, base tube, 3 AAA batteries, rectangle sponge hardware, rectangle sponge, 4.5 m (15') ground wire, insulating collar, ear bud, wrist strap, carabiner, Long Form Certificate of Calibration traceable to NIST, instructions, hard shell case, two year warranty
PosiTest LPD Complete
Includes contents of the Basic Kit, plus adaptable sponge hardware and extension hardware in a hard-shell case.
Adaptable Sponge Hardware
Extension Hardware
Available Accessories
