The Science Behind Heat Shrink Tubing

Heat shrink tubing is expanded plastic tubing that shrinks back to its original size when heat is applied to it. Heat shrink is used in a wide range of residential, commercial and industrial applications.

The Science Behind Heat Shrink Tubing

What Heat Shrink Is

Heat shrink is a tubular, plastic material that can be forced into an expanded state and then reverted into its relaxed state. The properties of heat shrink can vary greatly. For example, some tubes are rigid, have thick walls or only activate at relatively high temperatures.

How Heat Shrink Tubing is Applied

Heat shrink is applied by sliding it over the area to insulate and then applying heat to the area. Although a flame can work, it is generally advised to use a heat gun. The applicator can maintain a precise temperature and apply it evenly to the tube. For best effect, tubing is heated gradually by completing one small section at a time.

Shrink Temperature

There is no specific ideal temperature for heat shrink tubing. The temperature varies based on the materials and manufacturing process used. Typically, the tubing packaging will indicate the optimal temperature. If a higher temperature is used, the tubing will burn. If a lower temperature is used for too long a period, it will destroy the tubing’s ability to shrink.

What Heat Shrink Tubing is Made From

A heat shrink tubing manufacturer will typically use a thermoplastic material, such as polyolefin or nylon. Polyolefin is the most common material found in heat shrink that is intended for hobby and residential use. Other common materials include neoprene, PVC, silicone elastomer or fluoropolymer. The latter is common in industrial use because it is resistant to acids, bases and solvents.

How Heat Shrink is Made

The usual manufacturing process for heat shrink tubing is expansion based. The material is heated just above its melting point, stretched using a gas and then rapidly cooled. A secondary method is called cross-linking, and it uses electron beams to achieve a similar effect. The downside to cross-linking is that it is more expensive, but the upside is that the manufacturer has greater control over the shape after shrinking.

Types of Heat Shrink Tubing

Basic heat shrink is black. Colored tubing is available at an additional cost, which allows for color-coding of wires and connections. Heat shrink is also available in luminous and UV-reactive coatings that are popular among hobbyists such as PC modders and RC enthusiasts. Heat shrink is also available with a conductive lining, which allows the user to solder and insulate at the same time.


Heat shrink tubing is used in a wide range of applications, including electrical insulation, strain relief, splice sealing, mechanical protection, and wire bundling/identification – making it an invaluable tool in many different industries.

Heather B is part of a team of writers who publish blogs and articles on sites daily.