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CS-665 Non-Toxic Butyl Rubber Sealant

For self-sealing joints in: Drinking Water Cisterns and Potable Water Systems. Not intended for use in expansion joints or joints that move.

Technical Data


  • Provides permanently flexible watertight joints.
  • Excellent adhesion and structural integrity.
  • Bonds well to most surfaces, including: concrete, fiberglass, metal, plastic and aluminum.
  • Sealed joints will not shrink, harden or oxidize upon aging.
  • Controlled flow resistance for application ease.
  • Low to high temperature workability: 20°F to 120°F (-7°C to 48°C)
  • Rugged service temperature: -30°F to +200°F (-34°C to +93°C)
  • No priming normally necessary. When confronted with difficult installation conditions, such as wet concrete or temperatures below 40°F (4°C), priming the concrete will improve the bonding action. Consult Concrete Sealants for the proper primer to meet your application.


ConSeal CS-665 has been tested in compliance to the conditions specified in the Federal Hazardous Substance Act (16CFR 1500). Test Results conclusively show that CS-665 is classified as non-toxic by oral administration.

ConSeal CS-665 has been certified by NSF International to conform to the requirements of NSF / ANSI Standard 61 (Drinking Water System Components) Section 6. Joining and Sealing Materials.