Two part, low outgassing addition curing silicone for bonding, potting, sealing & coating

Key Features

  • Meets ASTM E595 specifications
  • Convenient handling
  • Optically clear
  • Highly flexible
  • Superb electrical and physical properties
  • Low shrinkage upon curing

Product Description

Master Bond MasterSil 971-LO is a two component silicone for high performance bonding, sealing, coating and encapsulating. Most importantly, it fully complies with NASA low outgassing test requirements. It is an addition cured system, it does not require air for curing. Consequently, it will crosslink in sections thicker than 1 inch. The handling is very user friendly; its mix ratio is one to one by weight and its working life is a convenient 3-4 hours. This clear silicone has excellent flow properties. The curing schedule is 20-40 minutes at 250-300°F or 1-2 hours at 160-200°F.

Upon curing, MasterSil 971-LO has top notch electrical insulation properties. Its physical strength properties are impressive as well. The lap shear strength, tensile strength and elongation are all quite good as noted below. It withstands the most rigorous types of thermal cycling and shock. Also, it has stellar electrical insulation properties. This performance and handling profile allows MasterSil 971-LO to be used in potting and encapsulation applications.

MasterSil 971-LO bonds well to a wide variety of substrates, including metals, composites, glass, ceramics as well as many types of rubber and plastics. Since it is an addition cured system, it can be used for bonding larger pieces. The system is 100% solids and its color is clear. The service temperature ranges from -120°F to +400°F. MasterSil 971-LO is part of a very special group of two part silicones that passes low outgassing tests. It can be used in the most challenging types of applications in the aerospace, electronic, optical and specialty OEM industries particularly when vacuum compatibility and flexibility are required properties and optical clarity is desirable.

Product Advantages

  • Readily processed, easy-to-mix one to one ratio by weight
  • Long open time with good flow after mixing
  • First class electrical insulator; good choice for potting and encapsulation
  • Fine physical strength properties
  • Remarkable optical clarity
  • Complies with NASA low outgassing requirements

Industrial Certifications

ASTM E595 Compliant



MasterSil 971-LO is available is various sizes and units to accommodate customer's needs.

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