It is important to select the correct probe for the application and to be aware that special probes do exist to make measurements possible and if necessary can be constructed for your application
Hand held instruments use either the magnetic induction or the eddy current method to measure simple coatings.
The measurements are non-destructive, simple and quick to make; the most important element in the measurement being the probe, says Fischer Instrumentation.
Its design determines the measurement accuracy.
Careful probe design will allow it to be used on curved surfaces and give accurate results even on thin steel substrates.
It will also accommodate some variations in the substrate material.
If the substrate is particularly rough, then a special probe may be required, maybe even a two-pole probe which increases the measurement area.
Probes can be right-angled for restricted access, with dimensions small enough for measuring inside tubes of only 7mm diameter.
For very soft coatings, a large surface area is required, which can be up to 75mm diameter.
Some probes will cope with 50mm thick coatings and in some special applications, up to 300mm.
It is important to select the correct probe for the application and to be aware that special probes do exist to make measurements possible and if necessary can be constructed for your application.
