Chalking Rate Tester according to Kempf Model 241

The Model 241 chalking rate tester consists of a light-metal cylinder. At the end of this cylinder is a 40-mm diameter rubber stamp and a Shore A hardness of 60 ±5. The built-in compression spring enables a stamping pressure of 50 to 250 N. The ring marks punched into the stamp shaft, stepped at intervals of 50 N, also allow the load to be less than the standard 250 N pressing force. Pressing by hand is too unpredictable to ensure a consistent load from the rubber stamp on the test surface. Therefore, we recommend using a special stand. The lever is used to apply the contact pressure more easily and precisely.