A brief guide to heat shrink tubing
How do you use heat shrink tubing? This guide is designed to answer that and other
questions, including how to heat shrink tubing. The purpose here is to help you understand what this process involves. We’ll cover:
- What is heat shrink tubing?
- Why use heat shrink tubing?
- Sizing heat shrink tubing
- Heat shrinking your tubing
- How to use heat shrink tubing safely
- Three common heat shrink tubing materials
- Heat shrink accessories
What is heat shrink tubing?
Heat-shrink tubing, also known as electrical shrink wrap or cable shrink sleeve, is a type of plastic tube that shrinks when exposed to heat. You use heat shrink tubing to insulate wires and protect and bind cables together or to repair a damaged cable’s insulation.
Is heat shrink tubing waterproof? Yes. It also comes pre-stretched with a shrink ratio. The example here is clear heat shrink, or clear heat shrink tubing, which is made of crosslinked polyolefin with a 2:1 shrink ratio. This means it will shrink to half its size. Tubing with a 3:1 shrink ratio will shrink by a third. Shrink ratio can go as high as 6:1.
Heat shrink tubing sizes vary to accommodate components and assemblies used in electronics, electrical and mechanical applications. You can also get different heat shrink tubing colours to colour code wires, cables, terminals and components.
Why use heat shrink tubing?
Using heat shrink tubing to protect wires improves the safety, reliability, and appearance of an electronic or electrical application. That’s not all, however. Heat-shrink use has multiple benefits, providing:
● Electrical insulation: Is heat shrink tubing conductive? No. Most heat shrink tubing offers electrical insulation to help prevent short circuits, electrical shocks, and other electrical hazards.
● Protection: Heat shrink tubing wrap acts as a protective barrier around the component, shielding it from physical damage, abrasion, and vibration.
● Organisation: Wire heat shrink tubing bundles wires and cables together, reducing clutter and making it easier to identify and access specific components. This can help save space and improve the overall appearance of the project.
● Sealing: Using shrink tubing seals the ends of wires and cables, preventing moisture and other contaminants from entering.
● Strain relief: Wires and cables often experience strain, which can affect their life span. By sleeving cables with heat shrink tubing, you can provide mechanical support by reducing strain on connector pins.
You can learn more about heat shrink tubing and how it compares to cold shrink tubing and electrical tape in A comparison: heat shrink alternatives.
Heat shrinking your tubing
These steps below give you an idea of how heat shrink tubing works. For best results, follow the heat shrink tubing instructions provided by the manufacturer. You’ll need scissors and a heat gun for shrink tubing.
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Step 1 |
Sizing heat shrink tubing: Measure the electrical wire or cable’s diameter. |
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Step 2 |
Choose a piece of heat shrink tube just large enough to slide over the wire.
Note, any heat shrink size chart is specific to the manufacturer.
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Step 3 |
Use a pair of scissors to cut the heat shrink tube. |
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Step 4 |
Slide your heat shrink tubing over the wires.
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Step 5 |
Make sure there are no flammable gases and liquids near you. |
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Step 6 |
Applying heat: The typical heat gun temperature for heat shrink tubing is 90°C, but it depends on the specific heat shrink tubing material you’re using. Always check the manufacturer’s technical sheet for the recommended heating temperature before applying heat. .
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You can learn more on how to measure heat shrink tubing in our guide, What is heat shrink tubing?
How to use heat shrink tubing without a heat gun
OEMs and cable assembly houses use a heat shrink oven. On a smaller scale, a hair dryer is possible as your heat source, but incredibly time consuming. Results are mixed. The main problem is that a hair dryer isn’t designed to reach 90°C. You can also try a small butane torch, but any open flame creates safety issues plus. If you do try this, take precautions and keep rotating the shrink cable sleeve so that the flame is not concentrated in one place longer than necessary.
How to use heat shrink tubing safely
You should always choose heat shrink tubing rated UL224 for flame retardancy. Also, your tubing should heat shrink without releasing dioxins. Follow our heat shrink tips within this guide for applying your tubing.
You should also familiarise yourself with the relevant safety standards for heat shrink tubing. You can learn more in our guide, What are cable protection standards?
Common heat shrink tubing materials
Materials typically used to manufacture heat shrink tubing have their own properties. You’ll need to balance the characteristics you’re looking for with your budget to determine the best material for your application.
● Polyolefin: Polyolefin heat shrink tubing is the most common material used due to its good electrical and mechanical properties. A thin-wall tubing, it also has chemical resistance while standing up to high temperatures. Its rigidity makes heat shrink tubing a good choice for mechanical protection.
In the example here, the heat shrink tubing is made of crosslinked polyolefin, also known as XLPO. This heat shrink tubing material is a form of insulation produced through heat and high pressure. Its most important characteristic is that it’s halogen free.
This makes it an excellent insulation and jacket material. Free from environmentally harmful substances, it doesn’t emit dioxin when burned. It has an operating temperature range between -55°C and 125°C, high flexibility and superior mechanical strength. With a shrink ratio of 2:1, it’s mostly used in specialist vehicles, communication, and electronics.
Adhesive lined heat shrink tubing in crosslinked polyolefin is an excellent choice for protecting heavier or more critical wires with a more robust casing. Heat shrink tubing with adhesive is thicker material, which makes the tubing less flexible and more stable. Its shrink ratio is 3:1. Non-adhesive heat shrink tubing with a shrink ratio of 3:1 is also available. Unlike adhesive lined tubing, this is thin wall tubing.
● PVC: Polyvinyl chloride (PVC) is a low-budget alternative to polyolefin heat shrink tubing. It’s unable to withstand the high temperatures suited to polyolefin, but it does provide good electrical insulation and durability. PVC heat shrink tubing resists moisture, oil and chemicals, which is why it’s generally used in automotive and marine applications.
● Fluoropolymer: Fluoropolymer heat shrink tubing includes polytetrafluoroethylene (PTFE). This material is highly resistant to chemicals, heat, and UV radiation, which is why it’s typically used in harsh-environment applications.
Heat shrink accessories
Electrical tape – a short-term solution – and special heat-shrink tape are available on the market, which can be used with heat shrink tubing for insulating seals and enclosures. You can also find heat shrink tubing kits, which consist of multiple, short-lengths of heat shrink tubes. You’ll also need a heat shrink tubing heat gun.
Download free CADs and try before you buy
Free CADs are available for most solutions, which you can download. You can also request free samples to make sure you’ve chosen exactly what you need. If you’re not quite sure which solution will work best for your application, our experts are always happy to advise you.
Whatever your requirements, you can depend on fast despatch. Request your free samples or download free CADs now.
Questions?
Email us at sales@essentracomponents.co.uk or speak to one of our experts for further information on the ideal solution for your application 0345 528 0474.