Master Bond MasterSil 323 is a two component silicone for high performance bonding, sealing, and encapsulating. It does not require air when polymerizing and does not outgas while curing. It has a forgiving one to one mix ratio by weight. The viscosity of both Parts A and B allows for easy mixing and good flow. It is a low exothermic material with a long open time of about 2-3 hours. It cures at ambient temperatures in 48-72 hours or in 2-4 hours at 135-165°F. The optimum cure is overnight at room temperature followed by 2-4 hours at 135-165°F. This silicone contains no solvents or diluents and has very low shrinkage upon curing. It has a Shore A hardness of 35 to 45.
MasterSil 323 bonds well to a wide variety of substrates including metal, glass, plastics and ceramics, as well as to silicone rubber. It can withstand the most rigorous kinds of thermal shock and cycling without cracking or exerting stress on components. The service temperature range is from -65°F to +400°F. Other noteworthy features are its optical clarity, especially in thinner sections, and its superior electrical insulation profile. MasterSil 323 should be considered in optical, electronic, aerospace, and specialty OEM applications where a high strength, optically clear, easy to use, silicone is needed.
Product Advantages
- Addition cured, no by-products released during cure
- Flowable, with long open time
- Optically clear, especially in thin sections
- Very low shrinkage upon cure
- Good bond strength, yet potentially removable
- Low dielectric constant
