How to use a Surface Comparator

In order to maximise a coating’s overall performance, it is essential to assess the surface profile of the blast cleaned substrate, as a profile that is too large or too small, can lead to costly premature coating failures.

If you are only required to quickly assess the surface profile of a blasted metal surface, then the easily transportable and easy to use Surface Comparators are the perfect choice. Put simply, comparators are a flat, steel plate which contain a number of reference surface profiles, formed on a corrosion resistant metal.

These reference profiles are then compared to the freshly blasted surface – many comparators have a hole in the middle to make this comparison easier - and a profile grade is then defined by the inspector. Due to the speed of the test, this method is especially useful when you want to go from blasting to painting as quickly as possible to avoid flash rust, or when measuring in hazardous areas where electronic equipment is prohibited.

Elcometer has a range of surface comparators for use with different standards and for different profile finishes, and they all work in the same way. Depending on which one you choose, the comparator will contain either four, five, or six reference profiles, with the profile values recorded in either microns, mils, or “classes”; again dependent on the comparator you are using.

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