The mandrel bending test determines a characteristic value for the elasticity, adhesive strength and elongation of a cured coating under bending stress.
A coated sheet is bent using a lever around a conical mandrel with a diameter of 3.2 to 38.1 mm. The resulting cracks usually start at the thinner end of the mandrel and continue towards the thicker end.
The maximum crack length is read on the scale and the associated mandrel diameter is determined. The size of the bending diameter, where no changes are visible yet, corresponds to the result of the test.
With the conical mandrel bending test, a large range of different bending radii can be recorded within one test.