Heat-shrink tubing

Heat-shrink tubing

Heat shrink tubing (or commonly "heat shrink") is a tube which shrinks in diameter when heated. Its diameter and thickness can vary, and there are three main categories, thin wall, medium wall and thick wall tube. Heat shrink is used to insulate wires, connections, joints and terminals in Electrical Engineering. It can also be used to repair wires, bundle wires together, and to protect wires or small parts from minor abrasion.


Heat shrink tubing is manufactured from a thermoplastic material such as polyolefin, fluoropolymer (such as FEP, PTFE or Kynar), PVC, neoprene, silicone elastomer or Viton.


It is placed over the connection to be protected and then heated with an oven, hot air gun or similar tool. Convenient but less effective methods for shrinking the tube include a soldering iron (held in close proximity, but not touching the tube) or the heat from a lighter. These processes cause the tubing to contract as far as one sixth of its original diameter (dependent on the heat shrink), providing a snug fit over irregularly shaped joints. This provides good electrical insulation, protection from dust, solvents and other foreign materials, as well as strain relief. If overheated, heat shrink tubing can melt, scorch or catch fire like any other plastic.

Some types of heat shrink contain a layer of thermoplastic adhesive on the inside to help provide a good seal and better adhesion, while others rely on friction from the closely conforming materials. Heating plain non-adhesive shrink tube to very near the melting point may allow it to fuse to the underlying material as well.


According to the exact material used, there are two ways that heat shrink may work. If the material contains many monomers then when the tubing is heated, the monomers polymerise. This increases the density of the material as the monomers become bonded together therefore taking up less space. Accordingly, the volume of the material "shrinks".

Heat shrink can also be expansion-based. This process involves producing the tubing as normal, heating it to just above the polymer's crystalline melting point and mechanically stretching the tubing (often by inflating it with a gas) finally it is rapidly cooled. Later when heated, the tubing will "relax" back to the un-expanded size.

The material is often cross-linked through the use of electron beams, peroxides or moisture. This cross-linking helps to make the tubing maintain its shape, both before and after shrinking.

For external use, heat shrink tubing often has a UV stabiliser added.

Heat shrink types

Heat shrink tubing is available in a variety of colours to allow easier colour coding of wires and connections. Recently heat shrink tubing has been used more in PC modding to tidy up the interior of computers and provide a more aesthetic finish. As a reaction to this new market opening up, manufacturers have started producing heat shrink tubing in luminous and UV reactive varieties.

Although most heat shrink is used to provide insulation, heat shrink tubing is also available with a conductive lining to avoid the requirement to solder a joint before covering it. This may be considered poor engineering practice.

Similar to heat shrink tubing is heat shrink end caps. Shaped like small mugs, these may be used to insulate cut ends of wires or cables.

Heat Shrink Tubing was invented by Raychem Corporation. Leading global producers today include Tyco (which owns Raychem), Sumitomo Electric Industries (through Sumitomo Fine Polymer), DSG Canusa (Shawcor), 3M, Shrinktek Polymers International, Grayline Inc., Ikebana and Frontec (Frontier Technologies Pvt Ltd).

See also

*Electrical wiring

External links

* [http://van.physics.uiuc.edu/qa/listing.php?id=519 How heat shrink tubing works]

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Cold shrink tubing — is an open ended rubber sleeve, made primarily from rubber elastomers with high performance physical properties, that has been factory expanded or pre stretched, and assembled onto a supporting removable plastic core. Cold shrink tubing shrinks… …   Wikipedia

  • Heat-shrinkable sleeve — (or commonly shrink sleeve ) is a corrosion protective coating for pipelines in the form of a wraparound or tubular sleeve that is field applied. History The first heat shrinkable sleeves were introduced over 35 years ago when polyethylene… …   Wikipedia

  • Shrink wrap — Shrinkwrapped redirects here. For the album, see Shrinkwrapped (album). Shrink wrap, also shrinkwrap or shrink film, is a material made up of polymer plastic film. When heat is applied to this material it shrinks tightly over whatever it is… …   Wikipedia

  • Heat gun — A heat gun is a device used to emit a stream of hot air. They are superficially similar in shape and construction to a hair dryer, though they run at much higher temperatures. They are often found in physics, materials science, chemistry,… …   Wikipedia

  • термоусаживаемая трубка — Специальная пластмассовая трубка, диаметр которой уменьшается при нагреве, применяемая для соединения деталей муфты кабеля местной связи или вместо муфты. [ГОСТ Р 50889 96] Тематики телефонные сети Обобщающие термины кабели местной связи, муфты,… …   Справочник технического переводчика

  • Opto-isolator — This article is about the electronic component. For the optical component, see optical isolator. Schematic diagram of an opto isolator showing source of light (LED) on the left, dielectric barrier in the center, and sensor (phototransistor) on… …   Wikipedia

  • Strange Change Machine — The Strange Change Machine was a Mattel toy from the late 1960s, in which shape memory plastic figures of prehistoric animals and so forth could be reconstituted from compressed time capsule form, and re compressed back into that form. It consted …   Wikipedia

  • Mobile fab lab — The mobile fab lab is a computer controlled design and machining shop housed in a trailer. The first was built in August 2007 by the Center for Bits and Atoms at the Massachusetts Institute of Technology.[1] The mobile lab includes the same… …   Wikipedia

  • HST — may refer to:* Harmonized Sales Tax * Harry S. Truman, thirty third President of the United States * Harvard MIT Division of Health Sciences and Technology * Hastings, a town in East Sussex, England * Hawaii Aleutian Standard Time Zone, UTC 10 *… …   Wikipedia

  • Rope — This article is about non metallic ropes. For other uses, see Rope (disambiguation). Coils of rope used for long line fishing A rope is a length of fibres, twisted or braided together to improve strength for pulling and connecting. It has tensile …   Wikipedia