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Heat Shrink Tube Guide

heat shrink

Introduction to heat shrink tube

Welcome to Railwayscenics comprehensive guide on heat shrink tubing! Whether you are a newcomer to the world of heat shrink or seeking to enhance your expertise, you have found the perfect page. Dive into the myriad uses and types of heat shrink tubing, along with tips and advice on selection and application techniques. Let us delve into the versatile realm of heat shrink tubing together!

What is heat shrink tubing?

Heat shrink tubing is a pre-stretched type of tubing made from a polymer material that shrinks in size when heat is applied. It is commonly used in electrical and electronic applications for insulation, protection, and bundling of wires, cables, and other components. Heat shrink tubing comes in various sizes, colours, and materials to suit different needs and environments.

Common materials used for heat shrink tubing include polyolefin, fluoropolymer (such as PTFE), PVC, and silicone. The choice of material depends on factors such as temperature resistance, chemical resistance, flexibility, and other environmental considerations.

Overall, heat shrink tubing is a versatile and practical solution for a wide range of electrical and electronic applications, providing protection, insulation, and organization in various industries and settings.

How heat shrink tubing works

Heat shrink tubing works by utilizing the properties of thermoplastic materials. When heat is applied to the tubing, typically using a heat gun or other heat source, the material undergoes a process called "shrinking" or "recovery."

Here's how it works step by step:

Application: The heat shrink tubing is slid over the area where it is needed, such as an electrical connection or wire splice.

Heat Application: Heat is then applied to the tubing evenly. The heat can come from a variety of sources, including specialized heat guns, ovens, or even simple lighters.

Shrinking Process: As the tubing is heated, the thermoplastic material within it begins to soften and expand. The tubing then shrinks down to a smaller diameter, conforming tightly to the underlying surface or object.

Sealing and Insulation: As the tubing shrinks, it creates a tight seal around the object it's covering. This seal helps to protect against moisture, corrosion, and other environmental factors. Additionally, the tubing provides insulation, preventing electrical shorts or other issues.

Cooling: Once the tubing has shrunk to its desired size and shape, it needs to cool down. As it cools, the material hardens again, maintaining its new shape and providing a secure covering or insulation.

Overall, heat shrink tubing is a versatile and effective solution for protecting and insulating electrical connections, splices, and other components in a wide range of applications.

What is heat shrink tubing used for?

Heat shrink tubing is used for a variety of purposes across different industries and applications. Some common uses include:

Electrical Insulation and Protection: One of the most common uses of heat shrink tubing is to insulate and protect electrical connections. It provides a layer of insulation that helps prevent electrical shorts, corrosion, and moisture damage. It is widely used in electronics, automotive wiring, and electrical repairs.

Wire Identification and Organization: Heat shrink tubing comes in different colours, allowing for easy identification and organization of wires and cables. It's often used to colour-code wiring systems, making it simpler to trace and troubleshoot connections.

Strain Relief: Heat shrink tubing can provide strain relief for cables and wires, reducing stress on connections and preventing them from becoming loose or damaged due to bending or movement.

Mechanical Protection: In addition to electrical insulation, heat shrink tubing can also provide mechanical protection for components such as wires, cables, and connectors. It helps to shield them from abrasion, vibration, and physical damage.

Waterproofing: Heat shrink tubing can create a waterproof seal when applied correctly, making it ideal for outdoor or marine applications where exposure to moisture is a concern.

Cable Bundling: Heat shrink tubing can be used to bundle together multiple cables or wires, keeping them organized and reducing clutter.

Repair and Splicing: It's commonly used for repairing damaged cables or splicing wires together. The tubing helps to secure the repair and provide insulation, restoring the integrity of the connection.

Overall, heat shrink tubing is a versatile and essential tool for electrical, mechanical, and DIY projects, providing insulation, protection, and organization for a wide range of applications.

How to select the right size of heat shrink tube

Selecting the correct size of heat shrink tubing is crucial for a proper fit and effective application. Here is how to choose the right size:

Measure the Object: Measure the diameter of the object you intend to cover or the circumference if it is a cable or wire bundle. Make sure to measure the widest part if the object is not uniform in diameter.

Determine the Shrink Ratio: Heat shrink tubing comes in various shrink ratios, typically ranging from 2:1 to 4:1. This ratio indicates how much the tubing will shrink in relation to its original size when heated. For example, a 2:1 shrink ratio means the tubing will shrink to half its original diameter.

Calculate the Required Size: Use the measured diameter (or circumference) of the object and multiply it by the shrink ratio. This will give you the diameter (or circumference) of the heat shrink tubing you need after shrinking.

Select a Size: Choose a heat shrink tubing size that is slightly larger than the calculated size to ensure it will fit comfortably over the object before shrinking. It is better to have a slightly larger tube that can shrink down than one that is too small and does not fit properly.

Consider Wall Thickness: Heat shrink tubing also comes in different wall thicknesses. Thicker walls provide better protection against abrasion and mechanical damage. Choose the appropriate wall thickness based on the level of protection required for your application.

Check the Manufacturers Specifications: Some manufacturers provide sizing charts or guides to help you select the appropriate heat shrink tubing size based on the diameter of the object you are covering and the shrink ratio of the tubing.

Test Fit: Before applying heat, slide the heat shrink tubing onto the object to ensure it fits properly and provides the desired coverage.

By following these steps and considerations, you can select the correct size of heat shrink tubing for your application, ensuring a secure and effective result.

How to buy heat shrink tubing

We sell heat shrink tubing in smaller sizes, as there is no real practical use for the larger sizes in railway modelling. We also only sell in one length but in many colours. All of our heat shrink tubing is of the 2:1 variety, which means it will shrink to half of its original size.

All you have to do is measure the wires you wish to protect and find a suitable size covering to meet your requirements.

The heat shrink tubing we sell

We stock heat shrink tubing in 1.6mm, 2.4mm 3.2mm, 4.8mm, and 6.4mm un-shrunk sizes in black, blue, clear, green, grey, purple, red, white, and yellow. All are available in 1.2m lengths in a 2:1 shrink ratio. Shrinking temperature starts at +70 degrees C and is totally shrunk at 115 degrees C.

We have started to stock shorter 240mm lengths of 3:1 adhesive-lined heat shrink tubes in black and red, and in 1.5, 2.4, 3.2, 4.8, 6.4, 7.9, 9.5, 12.7, 15 and 19.1mm sizes before shrinking.

We also have a small range of 3:1 non-adhesive lined tube, sold in short 300mm lengths and available in red and black. It is available in 1.5, 2.4, 3.2, 4.8, 6.4, 7.9, 9.5, 12.7, 15 and 19.1mm sizes before shrinking.

We also sell a few heat shrink tube kits, which contain a handy assortment of sizes, but only in one colour.

Our full range of heat shrink tubing can be found by clicking here.

Applying heat to heat shrink tubing

There are several methods for applying heat to heat shrink tubing, each with its advantages and suitable applications:

Heat Gun or Heat Gun Attachment: A heat gun is a common and effective tool for shrinking heat shrink tubing. It provides a controlled stream of hot air, allowing you to evenly heat the tubing. Heat guns typically have adjustable temperature settings, which can be useful for different types of heat shrink tubing and materials.

Lighter or Torch: A lighter or torch can also be used to apply heat to heat shrink tubing. However, this method requires more caution as the flame can be less precise and may cause uneven heating or even damage to the tubing if not used carefully. It is essential to keep the flame moving constantly to prevent overheating.

Soldering Iron: For smaller sizes of heat shrink it is possible to heat them with the heat from the tip of a soldering iron. This only really works successfully on smaller sizes and short lengths.

When choosing a method for applying heat to heat shrink tubing, consider factors such as the size of the tubing and objects, the level of precision required, and the availability of tools and equipment. Always follow safety precautions and manufacturers guidelines to ensure proper application and avoid damage to the tubing or surrounding materials.

How to use heat shrink tubing

Using heat shrink tubing correctly is essential for achieving secure and effective electrical insulation or cable bundling. Here are the steps to use heat shrink tubing properly:

Select the Right Size: Ensure you choose a heat shrink tube with a diameter slightly larger than the object you intend to cover. When heated, it will shrink to fit snugly.

Cut to Length: Cut the tubing to the desired length, ensuring it overlaps the ends of the object by at least 1/4 inch on each side.

Prepare the Surface: Make sure the surface you are applying the heat shrink tubing to is clean and free of any debris or contaminants. This ensures a better bond.

Slide onto the Object: Slide the heat shrink tubing over the object you want to cover. Ensure it covers the entire length you intend to insulate or bundle.

Apply Heat: Use a heat source such as a heat gun or a lighter to evenly apply heat to the tubing. Keep the heat source moving to prevent overheating in one area, which can cause uneven shrinking or damage.

Shrink: As you apply heat, you will notice the tubing begin to shrink and conform to the shape of the object underneath. Continue heating until the tubing has fully shrunk and there are no wrinkles or air pockets.

Cool Down: Allow the tubing to cool down naturally. Do not disturb it until it has completely cooled to ensure a proper seal.

Inspect: Once cooled, inspect the heat shrink tubing to ensure it has formed a tight seal around the object and there are no gaps or areas of weakness.

Following these steps ensures that the heat shrink tubing provides effective insulation or bundling, protecting the underlying components from moisture, abrasion, and other environmental factors.

Creative uses for heat shrink tube

Why just use a heat shrink tube as an insulation material on electrical joints. Here are a few other uses for this versatile material.

  • Stopping rattles
  • Preventing fraying of ropes, threads and shoe laces.
  • Colour coding just about anything that the tube will fit on.
  • As a replacement for insulation tape to bind cables together.
  • Adhesive lined heat shrink can be used to stop leaks in water pipes and hoses but only temporarily.
  • Fix broken glass arms instead of tape.
  • Insulate screwdriver blades.

There may be more, but this list does show what can be done using this product.


Hopefully that all made sense and you now have a better understanding of heat shrink tube and its use. You should see that heat shrink tubing is a versatile product that has many uses in the railway modelling world and can be used beyond its well known use in electrical and electronic work. Its ability to provide insulation, protection, and grip makes it invaluable in countless creative and practical endeavours. Whether you are a crafts enthusiast, railway modeller or automotive enthusiast, heat shrink tubing proves to be an indispensable tool, offering endless possibilities for innovation and customization. So, the next time you consider a project, remember the potential of heat shrink tubing as it may just be the perfect solution you did not know you needed.

Product links

We have talked a lot about heat shrink in this guide. The range of products stocked is quite large and consists of many different types. The complete range can be found in our Heat shrink Products area. From that link, you should be able to find the product you require using the sub-category listings.