Spark / Holiday Testers Bamr South Africa

Spark / Holiday Testers

Premature corrosion of a substrate is usually due to the failure of the coating. A major cause of failure is the presence of flaws in the finished coating.

Collectively referred to as a coating’s porosity the main types of flaws are described below:

Runs and sags – The wet coating moves under gravity leaving a thin dry film.

Cissing – Occurs when a coating does not re-flow to cover the voids generated by air bubbles being released from the surface of a coating.

Cratering – Occurs when the substrate is wet or if the coating has poor flow characteristics, thus creating voids in the coating.

Pinholes – Caused either 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 to a substrate, as the coating cures it can crack from internal stresses of the coating.

Under coating – Areas are not coated or the coating flows away from particular edges, corners of a substrate and welds.

Furthermore, over a rough surface profile, insufficient coating may leave the profile’s peaks exposed. The consequent cost of repairs and subsequent loss of production can be considerable. Early inspection for coating flaws will prevent the expense and inconvenience of a coating failure. Instruments used to detect coating flaws are referred to by many different names, these include spark or jeep testers, porosity or holiday detectors and pinhole testers.

High Voltage Technique

Locates all flaws in insulating coatings on conductive substrates, the high voltage technique can be used to test coatings up to more than 7mm thick. This method is ideal for inspecting pipelines and other protective coatings. Coatings on concrete can also be tested using this method.

A power supply generates a high DC voltage which is connected to a suitable probe with an earth return connected to the substrate. As the probe is passed over the coated substrate, a flaw is indicated by a spark at the contact point which sets off the alarm. This technique is suitable for identifying all of the flaws described above, however care is required on thin coatings.

Please click on the appropriate image or on the heading for more information about each instrument.

2 Jun 2021

Elcometer 260 UV Pinhole Flashlight

by Graham Duk | posted in: Pinhole / Porosity Detection, Spark / Holiday Testers, Sponge / Pinhole Testers | 0

The Elcometer 260 UV Pinhole Flashlight is battery powered and housed in a rugged aluminium case providing a quick, low cost method of testing coatings for pinholes. Featuring a three-Watt purple light emitting diode, the Elcometer 260 UV flashlight has a beam wavelength of 405nm (±5nm), which the human eye perceives as a purple light. Designed with a specialised diffuser lens that emits a smooth beam image (with no streaks, hot spots or dark spots) and used with National Surface … Read More

8 Apr 2015

Elcometer 280 Pulsed DC Portable Holiday / Spark Detector

by Graham Duk | posted in: Coating Inspection, Pinhole / Porosity Detection, Products, Spark / Holiday Testers | 0

The Elcometer 280 Pulsed DC Portable Holiday is a ‘stick type’ holiday detector which has been designed to make pulsed DC high voltage holiday detection safer, easier and more reliable than ever before. Using state of the art electronics, the Elcometer 280 allows users to inspect coatings – without connecting the earth return lead to the component substrate – ideal for inspecting large surfaces and pipelines. • Flashing display, bright LED and a user adjustable volume alarm indicates detection of … Read More

8 Apr 2015

Elcometer 266 DC High Voltage Holiday Detector

by Graham Duk | posted in: Coating Inspection, Pinhole / Porosity Detection, Products, Spark / Holiday Testers | 0

The Elcometer 266 DC Holiday Detector revolutionises high voltage DC testing of coatings porosity detection making it safer, easier and more reliable than ever before. The Elcometer 266 DC Holiday Detector can be used to test porosity on coatings up to 7.5mm thick and is ideal for inspecting coatings on pipelines and other protective coatings. This holiday tester features a built-in voltage calculator which will determine and set the correct test voltage based upon the test standard and the thickness … Read More