These test methods cover the non-destructive measurement of
the dry film thickness of nonmagnetic coatings applied over a ferrous base
material using commercially available test instruments. The test methods cover
the use of instruments based on magnetic measuring principles only.
Method A provides for the measurement of films using
magnetic pull-off gauges,
Test Method B provides for the measurement of films
using magnetic flux gauges.
These test methods are not applicable to coatings that will
be readily deformable under the load of the measuring instruments, as the
instrument probe must be placed directly on the coating surface to take a
reading.
how to use Testex's Press-O-Film Replica Tape with Spring Micrometer to determine surface profile depth
If we can cut open the applied coating or we need to test
the removed membrane, use Vernier Caliper:
C640 Thickness Tester (as per ISO 4593 / ISO 453 / ASTM D 6988 / ASTM F 2251 / uses high precision (of of 0.1micron) displacement sensor, supported by scientific structure and professional control technology, which makes C640 greatly improved in stability, repeatability and accuracy.
As per EN 1062-1:2004 (E) : Dry film thickness E, in micrometres, shall be calculated from the consumption, using the following equation:
E = (V NV / 100)
NV is the non-volatile matter content, expressed as a percentage by volume, determined in accordance with ISO 3233;
V is the consumption, in millilitres per square metre.
V is the consumption, in millilitres per square metre.
And the thickness are classifed as follows:
NOTE:
1. Due to the roughness of the surface of mineral substrates and due to the characteristics of the application methods, masonry coatings build up an uneven layer rather than a film of uniform thickness.
2. The film thickness is subject to recommendations of the manufacturer of the coating material, depending on the type and/or texture of the substrate, the application method used and/or special requirements.
3. The thickness E is calculated according to the theoretical consumption in laboratory. This value is used in all tests for the coating material or coating system.
4. For textured coatings and coatings with coarse or very coarse granularity (e.g. resin bound renderings) the classification E should be used. The thickness should be calculated from the consumption and stated as an average thickness, where the minimum thickness of the film can be lower and the total thickness given by the maximum grain size.
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