The Shore Hardness Scale is the international standard for measuring the hardness of rubber, plastic, and many non-metallic materials. Hardness, measured on a Shore A or D scale, is a material’s resistance to surface penetration. Knowing a material’s hardness can help you select the right material for a certain application.

How Do You Measure a Material’s Hardness?

The shore hardness tests are performed by creating an indentation on the plastic or rubber with a gauge called a Durometer. The Durometer is pressed down on the sample perpendicularly and a spring loaded presser-foot makes contact with the sample.  The gauge measures the resistance of the sample as it deforms.  The A and D Scale use different shaped presser-foots and spring tensions because softer materials will deform easier than harder materials.

What Materials Utilize the Shore Hardness Scale?

The Shore Hardness Scale is used on a vast array of products. Here is a sampling:

  • Gelsilicone
  • Chewing gum
  • Rubber
  • Silicone
  • Tire treads
  • Hard hats
  • Urethane plastic
  • Semi-rigid and hard plastics

Why Does the Shore Hardness Scale Matter?

When planning a project, it’s important to understand the utility of the plastic or rubber you’ll be using. Soft rubber flooring or cushion for a windowpane needs to have some ‘give,’ and the Shore Hardness Scale will provide a measurement to indicate its strength or how it will conform to another surface. In some applications, you’ll need rigid plastic for load-bearing or structural necessity like an electronic housing. Each material should be chosen wisely for installation to optimize the efficacy and safety of the project. 


When you need help finding the right material for your application, turn to BJB Enterprises, Inc. for mold making and casting supplies. Since 1970, BJB Enterprises in Tustin, CA, has provided high-quality polyurethane, silicone, and epoxy products to a variety of manufacturers across the world. Combining unmatched technical expertise and knowledge of materials, BJB helps customers find real-world solutions for their applications. Visit their website for an overview of their products or call (714) 734-8450 to discuss your company’s needs and vision today.