FIT Heat-Shrink Tubing

Ask Professor Watson: Heat-Shrink Tubing FAQs

Posted on Monday, September 15, 2014 by Dave Watson

Dave Watson, Director of Engineering, also known as Alpha Wire's resident wire and cable expert was prompted with the question below regarding heat-shrink tubing.  Check out Professor Watson's explanation!

Q. How do I choose the right FIT® Heat-Shrink Tubing material for my application?

A. First, think about how you wish to use FIT Heat-Shrink tubing. Is it for: bonding, breakouts, bundling, color coding, encapsulation, environmental protection? The list goes on and on. But what is most important to understand is the requirements of that application. The Heat-shrink tubing section of the Alpha Wire Master Catalog provides guidance on page 449 as to which materials are best suited for these, as well as other applications.

Q. What size FIT Heat-Shrink Tubing should I choose for my application?

A. The basic answer is in the question - size. A practical approach to determining the size of tubing to use is simply to use one that will shrink to about 75% of core it will shrink onto. This is where the specification for "maximum covered ID" comes into play. For example, to cover a cylinder of diameter 1-inch, a tubing with a maximum recovered ID of about 3/4" should be used. To cover a 1/2 inch bar, a tube with maximum recovered ID of 3/8-inch should be used. For sizing assistance, try the FIT Sizing Guide on the Alpha Wire website.

Q. What happens to the tubing wall thickness when recovered?

A. As the tubing is recovered, the wall thickness will increase slightly. Though, due to the recovery process (how it was shrunk) and the shape of the core over which the tube was shrunk, the wall thickness may not be uniform. This is why we specify the recovered wall thickness as a nominal value.


Alpha Wire offers a variety of heat-shrink tubing including the newest addition, FIT-221L low smoke, zero halogen heat-shrink tubing


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