• Impact test describes a method for evaluating the resistance of a dry film of paint, varnish or related product to cracking or peeling from a substrate when it is subjected to a deformation caused by a falling weight.

• The coating under test is applied to suitable, thin（normally metal）panels. After the coating has cured, a standard weight is dropped on the each panel from a height that will cause deformation of the coating and the substrate. The test can be carried out with the coated side of the panel facing upwards（i.e.towards the falling weight）or downwards（i.e away from the weight). By gradually increasing the height from which the weight drops, the point at which failure occurs can be determined.Films generally fail by cracking, which is made more visible by the use of a magnifier.

 The test can be carried out：

•    either as a “pass/fail” test, the test being carried out from one drop height and with a specified mass, so as to test compliance with a particular specification.

•    or as a classification test, to determine, by gradually increasing the drop height and/or the mass, the minimum mass and/or drop height for which the coating cracks or peels from its substrate.

 The manufacturer offers many different types impact testers according to different standards. These impact testers consist of a solid base with a guide tube support, some different weights hammers（falling weights）and some different diameters punches. Users can choose different size and weight hammer to simulate paint used different environments.