Thermofit Wraparound Duct Bands

 TWDB for Sealing Industrial HVAC Systems

An installed strip of TWDB (actually 2)

     If you are looking for TWDB - save some time and give us a call!  936/321-3333

     If you are looking for installation guidelines - check HERE

Thermofit Wraparound Heat Shrink Duct Bands (TWDB)*
This is a heat-shrinkable tape used for sealing joints in round air conditioning or heating ducts.

Product Overview:
TWDB is a sealing tape made for duct joints. It has a two-layer design:

• First Layer: Copolymer adhesive.
• Second Layer: A thick, high-density polyethylene material that's been cross-linked with radiation.

TWDB is a hot-applied tape with a heat-shrinkable backing, a heat-resistant pressure-sensitive adhesive, and a closure patch.

How It Works:
To apply, you use a propane torch. First, put the ducts in place. Then, wrap the tape around the joint and apply the closure. When you heat the tape above 120°C (250°F), it shrinks tightly around the duct joint. As it cools, the adhesive softens and bonds strongly to the surface, filling any gaps like interlocking seams. After cooling, the bond stays strong, creating a tough, pressure-tight seal.

Important Note:
This tape isn’t meant for use in industrial environments where there are solvents, oils, or chemicals.

Key Features & Benefits:

• No primer needed, so it’s quick and easy to apply.
• It’s low on preheat sensitivity and works really well, combining easy application with high performance.
• The strong backing resists vibrations in high-velocity systems up to 70°C (158°F).
• It helps cut down on inventory costs since you can cut it to the length you need, no need for different sizes.
• The sealant is specially designed for reliable protection, providing high peel and shear strength after it’s applied.
• No special equipment or skills needed – installation is fast and easy, which helps keep costs low.

Product Specs:

• Max. operating temperature: 70°C (158°F)
• Best for: Sealing galvanized ducts
• Prep: Make sure to remove moisture and surface oils
• Recommended pipe prep: ST3

TWDB is sold as a roll, and these are the available sizes:

• 165 ft roll, 3-inch width
• 165 ft roll, 4-inch width

(Closure patches included!)

Anode Splice Encapsulation Kit

 ASE-4 Anode Splice Encapsulation Kit

Cross section drawing of how ASE-4 seals between 2 cables

     Raychem's Anode Splice Encapsulation Kit is a heat shrinkable sleeve internally coated with with self encapsulating adhesive that enables it to completely insulate and seal such connectors as the standard split bolt and compression connector.

    The ASE is designed specifically for protecting anode splice connections of HMWPE, HDPE and Raychem Permarad cables (<--obsoleted), used in impressed current cathodic protection systems.

    Simplicity of design enables rapid and reliable installation.  A single splice encapsulation kit covers many cable sizes while eliminating time-consuming taping as well as compound mixing and curing.  The kits can be installed in approximately 3 minutes at temperatures as low as -40F.

    ASE splice encapsulation can be direct buried immediately after installation.  The completed encapsulation is mechanically strong, electrically insulated and sealed from moisture and contamination. 

Shrink Sleeve Closure Zippers

 Shrink Sleeve Closures - WPCPIV

Both Sides of a Covalence WPCPIV Closure Strip

     Every single wrap around shrink sleeve must have a closure strip in order for there to be a proper installation.  The sole purpose of the closure strip is to hold the sleeve in the shape of a tube as it shrinks down the conform to the substrate.  The closure strip (WPCPIV) has absolutely no coating or corrosion prevention function.

     If a wrap around shrink sleeve were used and a WPCPIV closure strip was not used; as the sleeve began shrinking, it would simply fall off of the pipe onto the ground.  

     As you can see in the above picture, the checkered side is the high shear adhesive side.  That is the side that goes down onto the shrink sleeve and prevents the sleeve from pulling away.  The bottom black side is simply the outer PE jacket which acts as the vehicle for getting the adhesive in place.

     Typically purchased in 4" sections, the closure strip would be wide enough to match the width of whatever wrap around shrink sleeve you are installing.  In some cases of large OD pipe; closures as large as 6", 8" or even 12" could be used.  We can make any size you need!