In the world of engineering plastics, the hardness of rubbers, elastomers, plastics, and other materials is measured on the Shore hardness scale. Shore hardness measures the level of resistance a material demonstrates against indentation pressure. The device used to perform this test is known as a durometer. Durometer devices measure the depth of indentation created in a material by force from a standardized presser foot. The resulting number is rated on the Shore hardness scale. The higher the number, the greater resistance to indentation a material displays.

In many applications, knowing the Shore hardness of materials is critical when determining which option will deliver optimal performance. Hapco, Inc. is a world-leading supplier of high-performance polymer formulations, including urethanes, epoxies, and other liquid molding technologies. Our products are used throughout demanding industries such as military and defense, medical device manufacturing, and many other applications where determining the hardness of a material is critical.

What is Shore Hardness?

Shore hardness measures the level of resistance a material has to indentation. These measurements are essential in providing a common understanding of a material’s hardness. All of the thermoset resins that Hapco formulates display varying levels of flexibility and hardness when cured, and Shore hardness scales provide a simple way to understand which material will work best in a certain project.

The Importance of Shore Hardness

In almost every application, the hardness or flexibility of a material is important to assess. Whether you're producing a delicate, thin-walled component or creating a foundry pattern that will need to withstand repeated abuse, Shore hardness scales make it easy to determine which materials are ideal for a specific use.

The Importance of Shore Hardness

Understanding the Shore hardness of a material allows you to identify whether or not the component will be flexible enough to not break when released from a rigid mold, or durable enough to stand up to heavy wear and extreme environmental conditions. Choosing the proper hardness of even a seemingly insignificant component, such as an o-ring or gasket, can make the difference between a project’s success and a disaster.

Shore Hardness Scales

The materials measured by Shore hardness scales are grouped into categories based on similarity. There are several durometer scales used to measure the hardness of a wide variety of substrates. At the time of its invention, scale A was devised to measure soft materials. As time went on and new harder materials were developed, additional scales were needed. In plastics engineering, the three most common scales include Shore A, Shore D, and Shore 00. These scales are used to measure non-metallic materials such as plastics and rubbers. Each Shore scale ranges from readings of 0 to 100, with 0 representing the softest possible material and 100 representing the hardest. Let's take a closer look at the three most common Shore hardness scales:

Shore 00

SHORE 00

This scale measures extremely soft types of rubbers and gels. Typical products measured using this scale vary greatly and include gummy candies and gel insoles for shoes.

Shore A

Shore A

This scale is used with a diverse range of materials, including very soft mold rubbers and semi-rigid plastics. Anything from rubber bands to the rigid soles of dress shoes and high heels is measured using this scale.

Shore D

Shore D

The hardest of rubbers are measured using this scale. These materials demonstrate little to no flexibility and include products such as PVC pipes and construction worker hard hats. Hard and semi-rigid plastics, as well as hard rubber, are measured on this scale.

Shore Hardness Scales

The materials measured by Shore hardness scales are grouped into categories based on similarity. There are several durometer scales used to measure the hardness of a wide variety of substrates. At the time of its invention, scale A was devised to measure soft materials. As time went on and new harder materials were developed, additional scales were needed. In plastics engineering, the three most common scales include Shore A, Shore D, and Shore 00. These scales are used to measure non-metallic materials such as plastics and rubbers. Each Shore scale ranges from readings of 0 to 100, with 0 representing the softest possible material and 100 representing the hardest. Let's take a closer look at the three most common Shore hardness scales:

  • Shore 00
    SHORE 00

    This scale measures extremely soft types of rubbers and gels. Typical products measured using this scale vary greatly and include gummy candies and gel insoles for shoes.

    SHORE 00
  • Shore A
    Shore A

    This scale is used with a diverse range of materials, including very soft mold rubbers and semi-rigid plastics. Anything from rubber bands to the rigid soles of dress shoes and high heels is measured using this scale.

    Shore A
  • Shore D
    Shore D

    The hardest of rubbers are measured using this scale. These materials demonstrate little to no flexibility and include products such as PVC pipes and construction worker hard hats. Hard and semi-rigid plastics, as well as hard rubber, are measured on this scale.

    Shore D

Contact Hapco for Your Next Project!

Countless applications rely on accurate Shore hardness readings to ensure the chosen materials will perform optimally. Once you’ve selected the most appropriate scale for the type of material you’re working with, you will quickly be able to determine if that material will meet your project’s requirements. This will not only save you time and money by ensuring you use the best material the first time, but it can also prevent the dangerous product failures and accidents that come when inappropriate materials are used.

Hapco, Inc. has half a century of experience formulating and manufacturing high-quality thermoset materials and their related equipment. As an ISO 9001 certified company, the materials and equipment we produce are reliably manufactured to ensure complete satisfaction. Our highly trained staff are experts at helping customers identify the ideal solution for each application. If you have questions about Shore hardness for your next project, reach out to our experts for help. You can also request a quote to get started.

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