Heat shrinkable tubing has a variety of uses. It is most commonly used as an insulator, to protect exposed wires and small contacts or components from the elements. Heat shrinkable tubing is often used as a weather seal to protect exposed components, or to fill in the area around the entry point of a cable – for example on outdoor electrical cabinets.
There are many different forms of heat shrinkable tubes. Some of them are designed to be very hardwearing, and can be used at extreme temperatures. Some are flame retardant, and some are designed to protect cables from rain or light water spillages. High grade heat shrinkable tubing is often resistant to more hazardous substances too.
The most popular variety of heat shrink tubing is made of polyolefin. This kind of tubing is quite durable, and has a maximum continuous operating temperature of between −55 and 135 °C. Polyolefin heat shrinkable tubing shrinks quite easily. There are products made of this material that will shrink at just eighty degrees Celsius.
Another material used in heat shrinkable tubing is PTFE – this is a fluoropolymer. It is resistant to most chemicals, and has a very wide operating temperature range (−270 to +260 °C). The main drawback of PTFE is that it has a much higher shrinking temperature, and as such can be used only by those with access to specialist equipment. A popular alternative to PTFE is Viton, which has a lower shrink temperature, but is still highly resistant to chemicals.
PVDF is a popular material for high temperature applications. This variety of heat shrinkable tube is low friction, and is resistant to abrasion, cutting, and ultraviolet and gamma radiation. The shrink temperature of PVDF is approximately 170 °C.
Neoprene heat shrinkable tubes are highly flexible even when exposed to low temperatures. These tubes are popular for military and aerospace applications.
Halogen was once popular in heat shrinkable tubes, but environmental concerns mean that it has fallen out of favour, and zero-halogen tubes are becoming increasingly common.
Consumer grade heat shrinkable tubes can be purchased online, or from the Maplin and RS Components catalogues. For more specialist applications, it is best to order directly from the manufacturer.
Heat shrink tubing is usually sold in 1 metre bundles, with discounts for large orders. Be sure to check the diameter and the shrink ratio of the tubing before you order, so that you can be confident that it will fit the cables or components that you wish to protect.