Testing for Pinholes with the Wet Sponge Method using the Elcometer 270 Pinhole Detector

The wet sponge technique is a quick and simple method for testing insulation coatings less than 500 microns (20 mils) thick on conductive substrates.
The Elcometer 270 Pinhole Detector provides both visual and audible alarms when a flaw is found, and it is incredibly easy to use.
CONTENTS
0:29 - How it works
1:19 - How to test using the Elcometer 270 Pinhole Detector
3:50 - Elcometer 270 accessories
When testing for pinholes on thin coatings, powder coatings, and other applications where you do not wish to damage the coating; typically the wet sponge technique, also known as the low voltage pinhole method, is used.
Put simply, a low voltage no bigger than 90 volts is applied to a damp sponge.
When you pass the sponge steadily over the coating, liquid from the sponge is drawn through any pinholes by capillary action; and when it touches the bare substrate, the current flows from the detector, through the substrate, and back to the detector through a signal return lead, which is clipped to an uncoated section of the substrate.
This completes a low voltage circuit, setting off an alarm on the detector, letting you know where you have a pinhole.
The Elcometer 270 is available in either dual or triple voltage models.
The dual voltage model can be set to 9V, for testing thin coatings up to 300 microns (12 mils) thick; and 90V, for coatings up to 500 microns (20mils). The triple voltage model can also test at 67.5V, the US standard test requirement.
Every time the tester is switched on or the voltage is changed, the Elcometer 270 automatically tests the calibration of the internal voltage and sensitivity.
Simple yet versatile, the Elcometer 270 is supplied with a standard wand and a universal flat sponge to suit most applications. However, there are a wide range of fully interchangeable accessories to suit different needs.
The Elcometer 270 is also available as part of a Pinhole Detector Inspector’s Kit; which includes the various wand adaptors, spare sponges, surfactant, and a 10m signal return cable. Simply choose your preferred model of Elcometer 270, and you have everything you need for low voltage flaw detection.
Testing on coatings up to 500 microns (20 mils) thick, the Elcometer 270 Pinhole Detector is the ideal gauge for detecting pinholes.
This video is part of the Elcometer Pinhole and High Voltage Detector series. Visit www.elcometer.com/en/videos to find out more.
For more information on the Elcometer 270 and the Elcometer 270 Pinhole Detector Inspector's Kit, please contact Elcometer at [e-mail] or visit our website: www.elcometer.com/en/coating-i...
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STANDARDS:
AS 3894.2, ASTM D 5162-A, ASTM G6, ASTM G62-A, BS 7793-2, ISO 8289-A, ISO 14654, JIS K 6766, NACE RP 0188, NACE SP 0188, NACE TM0384

[@sohailzafar7838]

Understood completely.

[@ahmedk.mahmood8244]

many thanks

[@raahemaarifat9900]

detergent water can also be used instead of tap water for conductance?

[@ElcometerOfficialChannel]

Thank you for your comment.
Yes, using a surfactant of any kind will help break down the surface tension of the water, helping it to more easily flow into any pinholes.
If you have any further questions, please contact [e-mail] or visit www.elcometer.com/contact-us to find your local Elcometer distributor.

[@Pam-oq9xd]

This is fascinating. Have you found success or failure with a minimum thickness? Can the voltage be lowered to compensate to almost any thickness?

[@ElcometerOfficialChannel]

Thank you for your comment.
Typically, coatings of any thickness under 500 microns (20mils) can be tested for pinholes using the Elcometer 270, as long as the coating is insulative.
The voltages in the Elcometer 270 are fixed to fall in line with the relevant ASTM, ISO and NACE standards.
9V is suitable for coatings up to 300 microns (12mils) thick, 90V is suitable for coatings up to 500 microns (20mils) thick, and 67.5V is the US standard test requirement.
If you have any further questions, please contact [e-mail] or visit www.elcometer.com/contact-us to find your local Elcometer distributor