In reply to The Potato:
> Surely there's not much in it between 62 and 60?
I shouldn't think so.
'Rubber' is one of those things I'm always a bit wary googling, but the bands seem to be both quite wide with gradual changes,
Shore 10-30A: Lowest on the rubber durometer chart are extremely soft and flexible rubber sheeting. Think of a rubber band, mouse pad, or gel insoles for your shoes. Only the softest materials will have a Shore rubber hardness in this low range, and such sheet rubber materials are not recommended for physically demanding applications.
Shore 40A: Rubber products with a 40A durometer will have a firm surface, but they are still very flexible and resilient. Materials at this lower-mid-range point of the rubber durometer chart are great for high impact applications such as protective padding or playground floors. A 40A durometer hardness is about as low as an elastomer can get while still providing a secure and stable walking surface. Such materials are ideal for providing flexibility and protection simultaneously.
Shore 50A: Rubber sheet rolls with a durometer of 50A are harder and more rigid than materials lower on the rubber durometer chart, but still offer an excellent range of flexibility. This Shore rubber hardness provides slightly more abrasion resistance and physical durability compared to the softer, 40A rated elastomers. This point on the rubber durometer chart is perfect for making parts for machinery such as seals, gaskets, and pads.
Shore 60A: This is the standard, mid-range durometer hardness. 60 durometer rubber has a stiff and sturdy surface, but maintains a moderate range of flexibility that works well in most applications. 60A durometer is one of the most popular ratings on the rubber durometer chart, as it provides excellent protection and unrivalled versatility compared to other materials. Such rubber rolls & sheeting offer impressive levels of abrasion and impact resistance without sacrificing stability, which is why 60 durometer rubber is the standard for general purpose applications. In fact, a 60 durometer rubber would make an ideal fit for a commercial gasket machinery that experiences heavy levels of service. This popular mid-point on the rubber durometer chart is also great for general purpose applications and it is usually a safe choice if you aren’t sure what exact durometer your application is going to need.
Shore 70A: Just a big harder than general purpose rubber, but still considered mid-range on the rubber durometer chart is the 70A durometer rating. A 70 durometer rubber has a small amount of flexibility, but is not recommended for pliable applications. The upper-mid point on the rubber durometer chart produces elastomers that are hard and rigid with impressive physical resistances. A 70 durometer rubber offers a surface with very little flex, but in turn can provide a resilient surface with heavy-duty protection from abrasions. This Shore rubber hardness is ideal for high-stress applications that do not require a flexible elastomer.
Shore 80A: As the hardest type of elastomer you will likely encounter, an 80 durometer rubber is very stiff, hard, and rigid. At the top of the rubber durometer chart, these hard elastomers have little to no flex to them at all. The stiff surface of an 80 durometer rubber offers virtually no comfort or cushioning, as seen in other mid-range durometer hardness ratings. Instead, that elasticity is traded for a dense and durable surface. An 80 durometer rubber can absorb any movement from heavy machinery abrasions to the subtle vibrations of sound waves, providing protection, soundproofing, and insulation in the process. The dense and solid surface of this higher mid-point of the rubber durometer scale is perfect for dealing with extreme sounds and temperatures. An 80 durometer rubber performs best in heavy-duty applications that require a dependable surface with little-to-no flexibility.
Shore 90-100A: Though elastomers at the very top of the rubber durometer chart are not the most common, they are not to be forgotten. A material that demonstrates a Shore rubber hardness above 80A is guaranteed to be extremely hard and rigid. Elastomers in this high range are likely to be so hard that they do not feel much like the rubbers we are used to. Such materials have essentially very little flex or pliability, and demonstrate extreme density when compared to other rubber materials. For most applications, an elastomer with a durometer between 40A and 80A is more likely to suit your needs, whatever they may be. A 90A or 100A durometer hardness simply cannot achieve the favorable versatility found within the mid-range of the rubber durometer chart.
