CRL M64 Gray Modified Polyurethane Construction Sealant Sausage

• One-part smooth finish formula with primerless adhesion on most common construction surfaces including KYNAR® coated metals
• AAMA approved
• VOC compliant — only 9 g/L
• UV resistant / non-yellowing

CRL M64 (SKU M64SGRY) is a one-part, moisture-curing, gun-grade modified polyurethane sealant formulated for moving joints. It typically requires no primer on common construction substrates and provides durable flexibility and long-term performance in perimeter and glazing joints.


Basic Uses
CRL M64 is designed to outperform traditional solvent polyurethanes in sealing moving joints in concrete, masonry, metal, and framing-to-structure applications. Ideal as a perimeter joint sealant for storefronts and curtain walls, it creates a watertight installation between doors, windows, and building structure. The advanced polymer adheres well to fluoropolymer paint coatings on metal — including KYNAR®, Duranar®, and Duranar® Sunstorm™ — and to aluminum, steel, galvanized steel, plastics, vinyl, glass, wood, concrete, brass, and other common building substrates.

CRL M64 is compatible with insulating glass sealants when used as a toe or heel bead. It is suitable for interior and exterior use, with service temperatures after full cure from -75°F to 300°F (-59 to 149°C). Paintable after two hours with water-based paints. Also used in manufacturing applications such as travel trailers, mobile homes, and galvanized HVAC duct assembly.

FEATURES
- Exceptional adhesion to KYNAR® coated metals — ideal KYNAR coated metal sealant for metal façade applications.
- Low-VOC, solvent-free, isocyanate-free formulation — only 9 g/L (chemically curing < 3%).
- Qualifies for LEED® EQ credit (Indoor Environmental Quality).
- Low-temperature gunning and application above 0°F (-18°C).
- Permanently flexible — resists hardening with age and remains flexible at low temperatures.
- Fast cure: skins over in ~30 minutes; cures ~1/8" (3 mm) per day.
- Tooling time: ~20–40 minutes depending on temperature and humidity.
- Paintable after two hours with water-based paints.
- UV resistant — will not yellow with sun exposure.

Technical Data
CRL M64 conforms to and passes:
Federal Specification TT-S-00230C, Type II, Class A.
ASTM C920-98, Type S, Grade NS, Class 25, Use NT, M, T, A, G, and O.
ASTM C510, C639, C661, C679, C717, C719, C793, C794, C1183, C1193, C1246, D412,