Master Bond introduces new bonding system 17 May 2022

Master Bond has introduced MasterSil 323, a two component, addition cured system for bonding, sealing and potting applications.

This product has a convenient to use 1:1 mix ratio and can be packaged in double barrel cartridges for dispensing from a gun applicator. It can be applied in thin and thick sections. This silicone has excellent flexibility, with an elongation of 150% - 250% at room temperature, a Shore A hardness of 35 – 45 and a low tensile modulus of 100 psi – 175 psi at 75°F for stress relief. It is capable of withstanding rigorous thermal cycling and shock without cracking or exerting stress on components. Additionally, MasterSil 323 has a low dielectric constant of 2.8 at 75°F, 1MHz.   

“MasterSil 323 is a speciality compound which not only offers strain relief upon cure, but also provides decent bond strength to a variety of substrates, especially considering that it is a silicone,” says senior product engineer Rohit Ramnath. “The lap shear strength for an aluminium to aluminium bond joint is around 200 psi – 250 psi at 75°F. Moreover, MasterSil is optically clear in thinner sections and has a refractive index of 1.44 at 589Nm. It has a wide service temperature range of -65°F – 400°F.”

The optimal cure schedule for MasterSil is overnight at room temperature followed by 2 – 4 hours at 135°F - 165°F. The material will fully cure without exposure to air or humidity. The working life of a mixed 100g batch is approximately 2 – 3 hours. It also has extremely low shrinkage upon curing. MasterSil is available for use in ½ pint, pint, quart, gallon kit containers, 30cc syringe kits, and 50cc double barrel cartridges for gun dispensers. Shelf life in original, unopened containers at 75°F is six months.


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