The hardness of a rubber compound directly affects the performance of that material in several ways, including its overall durability and flexibility. These factors can make a massive difference in the overall success of o-rings, vibration isolators, and many other parts. Let’s break down how durometer measures hardness and the durometer ranges for different rubbers and performance plastics.
Rubber Durometer Ratings
The Shore durometer scale allows experts to measure hardness by using a presser foot to see how much of an indentation is left after applying a set amount of force. Durometer is measured on an overlapping scale with three main categories, with shore A being the most common.
- Shore 00 – Very soft to medium hard
- Shore A – Soft to hard
- Shore D – Medium hard to very hard
The durometer of each rubber is also paired with a number that indicates the overall hardness of the material. The smaller the number, the softer the material within that shore. Each material is available in a range of hardnesses depending on the specific formulation of that compound.
EPDM hardness
Durometer Range: 30-90 Shore A
Other Key Benefits:
- Extreme resistance to weathering and physical wear and tear.
- Low toxicity and odor levels.
Silicone hardness
Durometer Range: 30-90 Shore A
Other Key Benefits:
- Excellent temperature resistance for both high and low temperatures.
- Tensile strength can be improved to roughly 1,500 PSA with fillers.
Neoprene hardness
Durometer Range: 30-90 Shore A
Other Key Benefits:
- Ideal for environments with intermittent exposure to oil and petroleum.
- Excellent resistance to twisting and flexing.
Nitrile hardness
Durometer Range: 20-95 Shore A
Other Key Benefits:
- Outstanding resistance to prolonged exposure to petroleum-based, mineral, and vegetable oils.
- Resistance to punctures, tears, and abrasion.
Viton hardness
Durometer Range: 40-90 Shore A
Other Key Benefits:
- Can operate in very hot and extremely corrosive environments.
- Can be formulated to meet strict environmental regulations regarding emissions, spills, and leaks.
Natural rubber hardness
Durometer Range: 40-90 Shore A
Other Key Benefits:
- Excellent ability to absorb vibration and reduce noise for even heavy-duty applications.
- Superior resistance to part fatigue.
Butyl rubber hardness
Durometer Range: 40-90 Shore A
Other Key Benefits:
- Completely airtight and gas impermeable.
- Excellent age resistance.
PVC hardness
Durometer Range: 15-70 Shore D
Other Key Benefits:
- Able to easily process and blend PVC into both rigid and soft materials.
- Extremely lightweight and low maintenance.
Thermoplastic elastomer (TPE) hardness
Durometer Range: 50-80 Shore A
Other Key Benefits:
- Offers a soft feel that is appealing to consumers.
- Provides both shock absorption and slip reduction.
Invest in Parts That Match Your Hardness Requirements
Hardness is one of many critical requirements that are essential for long-term part success. Timco partners with businesses to provide a wide range of solutions and supply them with parts that meet their exact specifications. Give us a call at 800-969-6242 or contact us online to invest in quality custom part solutions that address your design needs.
