How to Use Heat Shrink Tubing

You may not be fully aware but heat shrink tubing is a part of your daily life.  Heat shrink tubing is used on products ranging from phone cords to motor homes to airplanes and beyond.  Heat shrink tubing isn’t very difficult to install but can be a little intimidating if you’ve never done it before.  Below are some instructions to get you started with using heat shrink tubing.

We also have a post, “What is Heat Shrink Tubing?” where we answer a number of frequently asked questions for those new to heat shrink tubing.

Closeup of heat shrink melting

Watch the Step-by-Step,

“How to Use Heat Shrink Tubing,” Video

1. Identify Where You Need to Install the Heat Shrink Tubing

The first thing to do is identify where you want to install your heat shrink tubing.  In this example we are going to install heat shrink over an iPhone charging cable that has seen better days.  The cable has lost a portion of its cable jacket making the wire(s) underneath vulnerable.  Exposed wires like these can result in cables/wires not working, and in some cases exposed electrical wires are very hazardous.  Heat shrink tubing is a great way to cover the cable and resolve these issues.

2. Choose the Right Heat Shrink Tubing for Your Needs

If you’re new to heat shrink tubing, choosing the right tubing can be a bit tricky.  Heat shrink tubing comes in many different sizes, different shrink ratios, and there are many different types that offer unique characteristics.  The first thing to know is that heat shrink tubing sizes are listed in a before shrinking size.  So measure what it is you need the heat shrink to fit over and make sure you choose a size larger a little larger than that. To make sure our heat shrink tubing would fit over the iPhone cable and the connector at the end of the cable, we chose a 3/8 of an inch heat shrink tubing for this example.

The next thing to know, is the shrink ratio.  Shrink ratio measures the difference between the size of the tubing before and after it shrinks.  For example, we chose to use a 3 to 1, (usually written in ratio form as 3:1), heat shrink tubing on the iPhone cord, which means the tubing starts 3 times larger than what it shrinks down to.    We offer heat shrink tubing in 2:1, 3:1, 4:1, and 6:1 shrink ratios.

The last thing to be aware of when selecting your heat shrink tubing are any additional special qualities or characteristics that you might need.  For example, there are diesel and fluid resistant types of heat shrink out there, as well as heat shrink that is UV resistant.  For the iPhone cord we chose to use an adhesive lined heat shrink tubing that will make sure the heat shrink glues itself in place.

3.  Measure your Heat Shrink Tubing

Make sure to measure your heat shrink tubing so that it comfortably covers the exposed wire, or whatever vulnerability it is you want to cover.  It doesn’t have to be an exact science but you want the tubing to easily extend beyond whatever it is you want to protect.

You can mark where you would like to cut the heat shrink with a pencil to make things easier.

4.  Cut the Heat Shrink Tubing

Once you’ve measured the heat shrink tubing simply cut the tubing. The vast majority of heat shrink tubing can be cut with a normal, everyday pair of scissors.  

5.  Cover the Exposed Wire (Vulnerability) with the Heat Shrink Tubing

Once you’ve cut the heat shrink tubing, take the cut piece and place it on the cable in preparation to shrink it into place.

6.  Turn on Heat Gun

We highly recommend using a heat gun for installing heat shrink as heat guns reach the necessary temperatures for installing heat shrink in the safest way possible.  However, heat shrink tubing can be installed using a lighter, blow torches, or in some cases even a hair dryer.

Turn on heat gun

7.  Place Cable with Heat Shrink Tubing over the Heat

It’s time to start shrinking the heat shrink.  Take the cable with the heat shrink on it and put it over the heat gun, or whatever your heat source may be.  If there is enough heat the heat shrink should start shrinking almost immediately.

8. Rotate & Move the Heat Shrink Tubing While it Shrinks

In this example the heat gun is stationary, so make sure that you keep moving the heat shrink tubing so that it shrinks evenly and completley.  You also want to make sure that you don’t keep the heat in one place on the heat shrink for too long, as it can burn through the heat shrink and potentially damage the cable underneath.

In many installation cases, the heat shrink might be stationary while the heat gun/heat source is what is moving.  Regardless of the methodology, make sure that the heat source does not stay in one place for too long and that the heat gets all around the tubing for an even and complete installation.

9.  Installation is Complete

You will be able to see that the heat shrink has conformed to what is underneath it, in this case the cable and connection.  Make sure you don’t touch the heat shrink as it will still be hot. Let it cool and you are done.

Watch the Step-by-Step,

“How to Use Heat Shrink Tubing,” Video