Guide to pinhole testing with the Elcometer 270 Pinhole Detector using the low voltage wet sponge method, covering setup, voltages and accessories.
This guide explains how to test for pinholes with the Elcometer 270 Pinhole Detector using the wet sponge method, also called the low voltage pinhole method. The technique is described as a quick and simple way to test insulating coatings less than 500 microns (20 mils) thick on conductive substrates, applying a low voltage of no more than 90 volts to a damp sponge.
The text walks through connecting the signal return cable to an uncoated part of the substrate, wetting the sponge with clean tap water and squeezing out the excess, switching on the detector and passing the sponge over the coating. It describes the dual voltage (9V and 90V) and triple voltage (adding 67.5V) models, the automatic calibration test at power-up or voltage change, and interchangeable accessories such as the roller sponge wand, separate wand adaptor, belt clip, telescopic wand adaptor extending up to 1m, and the Pinhole Detector Inspector's Kit.
| Maximum coating thickness | 500 microns (20 mils) |
|---|---|
| Voltage settings (dual voltage model) | 9V for coatings up to 300 microns (12 mils); 90V for coatings up to 500 microns (20 mils) |
| Voltage settings (triple voltage model) | Also tests at 67.5V, the US standard test requirement |
| Battery | 3 AA batteries, up to 200 hours use |
| Alarms | Visual and audible |
| Signal return cable (standard) | 4m |
| Signal return cable (optional) | 10m |
| Telescopic wand adaptor | Extends up to 1m in length |
It is a low voltage pinhole method for testing insulation coatings less than 500 microns (20 mils) thick on conductive substrates, using a damp sponge at no more than 90 volts.
The dual voltage model can be set to 9V or 90V, and the triple voltage model can also test at 67.5V.
Thoroughly wet the sponge with clean tap water, then squeeze out the excess so it is damp but water is not dripping freely from it.
A surfactant significantly reduces the surface tension of the water, allowing the moisture to penetrate the smallest pinholes.