3M 7100189974 Aluminum Foil Tape 3340 2.5 in X 50 Yd

Product Description

The 3M 7100189974 is an aluminum foil tape — product series 3340 — designed for sealing, joining, and patching in HVAC, ductwork, and industrial applications. The silver foil backing conforms to irregular surfaces and forms a durable vapor and moisture barrier once applied. A pressure-sensitive acrylic adhesive provides strong initial tack and long-term adhesion to metal substrates, insulation facings, and flexible duct materials. Each roll measures 2.5 inches wide by 50 yards long. The foil construction offers high-temperature stability and tear resistance, making it suitable for both new assembly work and field repair or maintenance situations. HVAC technicians and sheet metal contractors are the primary installers.

This tape is used across residential and commercial HVAC installations where airtight duct sealing is required. Common applications include sealing duct board seams, wrapping ductwork insulation, patching metallic duct assemblies, and covering vapor barriers. It performs on rigid sheet metal duct, flexible duct collars, and insulated duct panels. The foil face is also used on refrigeration insulation and industrial pipe insulation where a metallic, moisture-resistant surface finish is needed. It is well suited for both shop fabrication and field service environments.

Key Features

• Pressure-sensitive acrylic adhesive delivers strong initial tack on metal, insulation facings, and flexible duct surfaces
• Silver aluminum foil backing conforms to irregular and curved surfaces
• Forms a durable vapor and moisture barrier at duct seams and insulation joints
• High-temperature stable construction suited for HVAC supply and return duct systems
• 2.5-inch width and 50-yard length provide extended coverage per roll
• Suitable for new installation, repair, and maintenance applications

Compatibility

Designed for use on rigid sheet metal ductwork, duct board, flexible duct assemblies, and insulation facings in HVAC and industrial applications.

Installation Notes

Applied by HVAC technicians and sheet metal contractors following SMACNA duct construction standards and applicable mechanical codes. Clean and dry all surfaces before application to ensure full adhesive contact. Apply firm hand pressure across the full tape width after positioning to activate the adhesive bond. Avoid stretching the tape during application on curved surfaces to prevent edge lifting over time.

Technical Specifications

• Width: 2.5 inches
• Length: 50 yards
• Backing Material: Aluminum foil
• Adhesive Type: Pressure-sensitive acrylic
• Color: Silver
• Series: 3340

Standard Information

• Brand: 3M
• Manufacturer Part Number: 7100189974