Hardness of Adhesive, Sealant and Coating Formulations

Master Bond formulations are available in a wide range of hardnesses. Compounds are designed to optimize performance and productivity.

Master Bond hardness testing is based on ASTM D 2240. Commonly used hardness scales are A and D. Shore A is used for softer materials, whereas shore D is used for harder materials. In order to measure the hardness, the sample is first placed on a flat surface, and the indenter is pressed into the sample. This test is usually repeated a few times at different locations on the sample, and the average reading is then used as the hardness.

The chart below offers an overview of the hardness range (Shore A and Shore D) available in our vast product line:


Hardness of Master Bond Product Line
Product Range of Hardness (Shore A/Shore D)
Silicones 30-55 A
Polyurethanes 80-95 A
Polysulfides 35-40 D
Epoxies: Flexible 35-60 D
Epoxies: Rigid 70-90 D
Common Hardnesses for Comparison
Material Hardness (Shore A/Shore D)
Rubber band 30 A
Car tire tread 60 A
Golf ball 60 D
Bone 100 D

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