A Guide to Applying Heat-Shrink Tubing

Posted on Wednesday, October 8, 2014 by Dave Watson

A Guide to Applying heat shrink tubing

Heat shrink tubing is versatile, protecting your cables against abrasion, chemicals, and weather. It is also great for bundling, color-coding and strain relief. Insulating your Acables, terminations, and other devices with heat shrink tubing is easy—so long as you follow proper procedures as outlined below.

Step 1

Select the proper size of heat shrink tubing for your project. In order to get a secure fit, be sure that the tubing’s recovered diameter (the diameter after shrinking) is smaller than the diameter of the area you’re going to insulate. At the same time, the tubing’s expanded diameter (the diameter before shrinking) needs to be large enough to easily fit over the area to be insulated, as well as any connectors attached to it.

Step 2

Cut the heat shrink tubing to a usable length, and be sure to allow for a minimum 1/4" overlap over any existing insulation or connectors. Keep in mind that tubing also shrinks lengthwise…typically 5-7% during the shrinking process.

Step 3

Slide the cut tubing over the object that you’re covering; if you’ll be splicing, slide the tubing over the center of the splice, and allow for equal overlap on both sides.

Step 4

Before shrinking, check your tubing’s specifications for the recommended heating temperature. Any commercial heat gun or heat shrink oven can be used to shrink the tubing. Since uncontrolled heat can cause uneven shrinkage, physical damage and insulation failure, the use of open flame is not recommended.

Step 5

If you’re covering a long length of cable with tubing, begin shrinking at one end, and gradually work your way down to the other. To ensure that the tubing shrinks evenly and without air bubbles, rotate the project as you’re applying heat.

Step 6

Evenly apply heat over the length and around the diameter of the tubing, until it is uniformly shrunken and conforms to the shape of the cable, hose, or splice that it’s covering. Immediately remove the heat source, and allow the tubing to cool slowly before you apply physical stress to it.



Avoid overheating the heat shrink tubing, because it will become brittle or charred.


Silicone lubricant spray can be applied to wires or cords to guide heat shrink over them without compromising the heat shrink material


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