Dymonic® FC is a high-performance, fast-curing, hybrid sealant manufactured by Tremco, known for its durability, flexibility, and strong adhesion to various building materials. It's designed to seal dynamic, moving joints in applications like window and door perimeters, precast concrete, EIFS, and masonry. Its "FC" stands for fast-curing, with a skin time of about one hour, which reduces dirt pickup compared to other sealants.  
Key Features
Fast Curing: Skins in about one hour at 70°F (21°C), reducing dirt pickup. 
Hybrid Technology: Uses silane end-capped polymer technology, offering the best characteristics of polyurethanes and silicones. 
Low Modulus: Remains flexible, allowing it to withstand movement in joints. 
Tenacious Adhesion: Creates a strong, long-lasting bond to many common building substrates without priming. 
Versatile: Suitable for expansion/control joints, perimeter caulking, precast concrete, EIFS, and more. 
Durable & Flexible: Designed to endure shear, deflection, and weather, maintaining a strong adhesive bond. 
Common Applications 
Precast concrete panel joints
Expansion and control joints
Perimeter caulking for windows, doors, and panels
EIFS (Exterior Insulation and Finish Systems)
Aluminum and masonry
Vinyl siding
Important Considerations
Surface Preparation: Surfaces must be dry, clean, and free from contaminants. 
Priming: While it often doesn't require a primer, a field adhesion test is recommended, especially for varied finishes like Kynar or anodized aluminum. 
Limitations: Do not apply to damp or contaminated surfaces, and avoid painting over it, as the paint may crack or peel due to joint movement.