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Pinhole & Porosity
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Premature corrosion of a substrate is usually due to a coating failure. A major cause is the presence of flaws in the finished coating.
Elcometer specializes in products designed to identify the location of coating defects after the coating has cured. Rugged, shockproof, and water resistant, the Elcometer range of DE, Pulsed DE, and low voltage Holiday Detectors are designed to meet the most exacting specifications. Ergonomic features and interchangeable probes make Elcometer's range the most versatile in the industry.
Learn about continuous DC vs. pulsed DC
The main types of flaws are:
- Runs & Sags: Coatings move under gravity leaving a thin dry film.
- Cissing: When a coating does not re-flow to cover the voids generated by air bubbles being released from the surface of a coating.
- Cratering: If the substrate is wet or the coating has poor flow characteristics, voids are created in the coating.
- Pinholes: Caused by air entrapment which is then released from the surface, or by the entrapment of particulates (dust, sand etc.) which do not stay in place.
- Over Coating: If too much coating is applied, as it cures internal stresses of the coating can cause it to crack.
- Under Coating: Un-coated areas, or where the coating flows away from edges or corners of a substrate or welds. Insufficient coating over a rough surface profile may also leave the peaks of the profile exposed.
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Pinhole detection is essential to monitor the integrity of the protective coating from its initial application to the end of its service life. Pinholes are caused by air entrapment, which is then released from the surface, or by the entrapment of particulates (dust, sand etc.) which do not stay in place. Elcometer offers a range of Pinhole Detectors from the low cost UV Pinhole Detector Flashlight to the full Pinhole Detector Inspectors Kit.
Visit Pinhole Detection methods explained for more information on Pinhole Detection, and selecting the correct model.
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Holiday testing is a non-destructive test method applied on protective coatings to detect unacceptable discontinuities such as pinholes and voids. The test involves checking an electric circuit to see if current flows to complete the circuit. This testing is used to find coating film discontinuities that are not readily visible.
The testing is usually performed on tank interiors, chemical storage vessels and buried structures because of the importance of maintaining adequate coating protection in aggressive service environments.
Holiday testing is also known as continuity testing.
Click for more information on finding the right holiday detector for your application.
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The Elcometer ElcoPatch Holiday Repair Kits are essential for coating
repairs. They make preparation and repair of identified pinholes and holidays easy. Other benefits include Other benefits include lower environmental and cost
impact through the reduced use of coatings, regulatory compliance, all
whist creating a consistent and sustainable solution for critical coating
repairs.
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