How Does Heat Shrink Tubing Work?

by Andy on November 12, 2012

Heat Shrink TubingIf you think about it, heat shrink tubing works in the opposite way that most would imagine. Many objects expand when heated and contract when cooled, so the term “heat shrink tubing” almost sounds like an oxymoron. However, the key to how heat shrink tubing works lies in how it is made.

When heat shrink tubing is created its original diameter is what you would typically think of as the “post-shrinking” size. To make the tubing have a larger diameter it is heated to near its melting point and then expanded, typically by inflating it with a gas. After the tube is expanded then it is rapidly cooled so it retains its new shape. This is what makes heat shrink tubing work, as when you heat the tubing up it becomes soft and contracts to its original size.

The dimensions for heat shrink tubing make a lot of sense when you look at the production process. Most heat shrink tubing talk about the “expanded inner diameter” which is logical when you realize that the tubing’s normal state is the post-shrinking size. The shrink ratio is also determined during the production process, as you can make the ratio go from 2:1 to 3:1 by expanding it more when it is made.

Do you have any other questions on heat shrink tubing? Post below in the comments or call customer service at (800) 537-0351!

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