Shore durometer measures a materials resistance to permanent indentation (one of several measures of hardness). Its normally used to measure plastic and rubber, which have some resistance to permanent change. Durometers compare relative results only, and this quantity therefore has no units. A durometer uses one of many possible scales due to the wide range of hardness that flexible materials may have. The specific properties of the material being measured will determine the proper scale to use.Durometer is one of several measures of the hardness of a material. Hardness may be defined as a materials resistance to permanent indentation. The durometer scale was defined by Albert F. Shore, who developed a measurement device called a durometer in the 1920s. The term durometer is often used to refer to the measurement, as well as the instrument itself. Durometer is typically used as a measure of hardness in polymers, elastomers and rubbers.There are several scales of durometer, used for materials with different properties. The two most common scales, using slightly different measurement systems, are the ASTM D2240 type A and type D scales. The A scale is for softer plastics, while the D scale is for harder ones. However, the ASTM D2240-00 testing standard calls for a total of 12 scales, depending on the intended use; types A, B, C, D, DO, E, M, O, OO, OOO, OOO-S, and R. Each scale results in a value between 0 and 100, with higher values indicating a harder material.

           2.Examine the meaning of a durometer reading. A material that does not indent at all under a particular scale has a durometer reading of 100 on that scale. A material that allows the maximum indentation (2.5 mm on the A and D scale) has a durometer reading of 0

           3.Study the parameters for the durometer scale you intend to use. The A and D scales both require you to take the measurement at least 12 mm from the edge of the material and the required pressure must be applied for 15 seconds. Furthermore, the material must be at least 6.4 mm thick. If the material is thinner than this, you can use additional layers of the same material to achieve this minimum thickness

           4.Take the durometer reading using the specific parameters for the scale youll be using. Apply the spring-loaded foot of the durometer to the material with sufficient force to make the spring begin to compress. This force should be 0.822 kg for a type A durometer and 4.55 kg for a type D durometer