Addition Cured Silicone is Optically Clear with Enhanced Low Temperature Serviceability

Ideal for potting and encapsulation applications, MasterSil 157 is a two component silicone system that features low viscosity and low exotherm. It has superior electrical insulation properties and can cure in sections beyond 1 inch thick.

MasterSil 157 is serviceable over the wide temperature range of -175°F to +500°F [-115°C to +260°C]. “This product was formulated for applications that require a silicone to operate under low temperatures,” said Venkat Nandivada, manager of technical support. “Typically, silicones are better suited to withstand high temperatures, so MasterSil 157 fills that need.”

Similar to traditional silicones, MasterSil 157 is highly flexible with an elongation of 110-140%, enabling it to withstand rigorous thermal cycling and shock. Featuring a refractive index of 1.43, it has excellent optical clarity and the ability to transmit light from 220-2,500 nanometers. “Its optical clarity makes it a good fit for many applications in the optical industry like optical fiber cladding and encapsulating LEDs,” said Nandivada. MasterSil 157 can also be used in the opto-electronic and specialty OEM industries.

This addition cured system does not require exposure to air for complete cross-linking. It has a ten to one mix ratio by weight and will not outgas while curing. MasterSil 157 also offers a long pot life of 2-4 hours at room temperature for a 100 gram mass.

MasterSil 157 is available for use in ½ pints, pints, quarts, gallons and 5 gallon container kits.

Master Bond Potting and Encapsulation Compounds

MasterSil 157 has good flow and electrical insulation properties, enabling it to be well suited for potting, sealing and encapsulation applications. Read more about Master Bond’s potting and encapsulation compounds at

contact Tech Support. Phone: +1-201-343-8983 Fax: +1-201-343-2132 Email:

About Master Bond

Since its founding in 1976, Master Bond has been committed to developing epoxies, silicones, light curing systems and other specialty adhesives that meet specific customer requirements. Master Bond manufactures over 3,000 grades of specially designed formulations that are widely used across a variety of industries including electronic, medical, aerospace and optical.

For a full product description, please visit:


James Brenner,

Marketing Manager


Tel: +1-201-343-8983

Fax: +1-201-343-2132


154 Hobart Street

Hackensack, NJ 07601-3922

United States


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