What is Hardness?

Hardness is a relative description of a material's ability to resist penetration of a metal conical indentor known as a durometer.  There are many types of hardness tests.  At FAI, we perform Shore A, Shore D, Shore M, and Shore OO.  These durometers are mostly used to test plastics and polymers. Due to the relative nature of hardness testing, there is no direct correlation between different Shore hardness scales.

Shore A

Shore A is used for hardness testing of softer plastics such as rubbers and fluoropolymers found in products such as tires, wiper blades, gasket seals, and much more.  It is recommended that Shore A be used when Shore D results are less than 20.

Shore D

Shore D is used to characterize harder plastics such as polyester, PVC, and acrylics.  Shore D is recommended when Shore A results are over 90.

Shore M

The Shore M hardness test was developed as an industry standard for small products that do not satisfy the requirements for Shore A and Shore D hardness testing.  Shore A and Shore D require a flat piece of material to test on.  Also referred to as "microhardness," Shore M allows hardness testing on irregularly-shaped products such as O-rings.

Shore OO

The Shore OO hardness test was developed for extremely soft materials such as gels and gums.

Related Services: Impact Testing

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