Red Devil NB0841DI F-seal Duct Sealant 1 Gallon Gray

Product Description

The RED DEVIL NB0841DI is a fiber-reinforced, water-based duct sealant formulated for pressure sealing HVAC duct systems in both indoor and outdoor applications. Sold in a 1-gallon pail, this gray sealant bonds to metal, fiberglass duct board, and flex duct, making it a versatile option for a wide range of residential and commercial ductwork installations. It delivers excellent adhesion and flexibility while maintaining a low VOC content. The formula is mold and mildew resistant and meets or exceeds all SMACNA pressure and sealing class requirements. Fast dry time helps reduce callbacks and keeps installations on schedule.

This sealant is appropriate for use on high, medium, and low-pressure HVAC duct systems. It is suited for metal ducts, flexible ducts, vents, air conditioners, and general HVAC appliances. HVAC technicians and sheet metal contractors apply it during new construction and retrofit ductwork projects where a durable, code-compliant seal is required. Indoor and outdoor rated, it holds up in unconditioned spaces such as attics, crawlspaces, and mechanical rooms where temperature and humidity fluctuate.

Key Features

• Fiber-reinforced formula for durable, long-lasting duct seals
• Rated for high, medium, and low-pressure HVAC duct systems
• Exceeds all SMACNA pressure and sealing class standards
• Indoor and outdoor rated for use in unconditioned and exposed spaces
• Mold and mildew resistant formulation
• Low VOC, water-based formula with fast dry time

Compatibility

Compatible with metal ducts, fiberglass duct board, flex duct, vents, air conditioners, and HVAC appliances. Listed to UL standards for applicable duct sealing applications.

Installation Notes

Applied by licensed HVAC technicians or sheet metal contractors using a brush, trowel, or caulk gun depending on joint configuration. Power down the air handling system before applying sealant to duct joints. Surfaces should be clean, dry, and free of oil or loose material before application. Follow local mechanical codes and SMACNA guidelines for joint preparation and sealant coverage requirements.

Technical Specifications

• Container Capacity: 1 Gallon
• Container Type: Pail
• Color: Gray
• Formula Type: Fiber-Reinforced Water-Based
• Application: Metal and Flexible Ducts, Vents, Air Conditioners, HVAC Appliances
• Applicable Standard: UL

Standard Information

• Brand: RED DEVIL
• Manufacturer Part Number: NB0841DI