How to Use Heat Shrink Tubing

Heat shrink tubing is used for isolating or insulating wires. Activated by heat, these plastic tubes shrink around the wires or exposed connections they are meant to protect. The tubing comes in various diameters, from 1/16 inch up to several inches.

Heat shrink tubing can fix resoldered headphone wires.

Lengths can vary, from packs of 6-inch lengths of various widths or longer 36-inch pieces.

  1. Measure the length of the exposed wire to be covered by the tubing. Add 1 inch to either side of the joint for the overall length. If the joint is 1 inch long, then the total length of the needed tubing will be 3 inches. Cut three pieces if you are joining paired wires; one for each wire and a longer, thicker piece to shield both.

  2. Cut the tubing with the scissors to the desired length. Slide the piece of tubing over one of the wires to be joined. Connect the two wires. These wires can either be twisted together or soldered. If soldering, be sure to have the tubing well away from any heat source. If you are joining paired wires, push the thicker tubing over the paired wires, away from the heat source as well.

  3. Slide the tubing over the finished joint. If the joint is soldered, allow it to cool first. Center the tubing over the two wires and the connection.

  4. Plug in the heat gun and begin to warm the tubing. You will observe the tube beginning to shrink after a few seconds. If smoke rises from the plastic, pull the gun back a little. Continue to heat until all the tube is tight against the wires and connection. Repeat for the second wire of a pair if present.

  5. Allow the heat shrink to cool fully. Pull the wider tubing over the paired wires if present and similarly heat shrink it.

  6. Tip

    You can also make a simple joint by sliding the tube over a number of wires. Twist the wires together, solder if needed and then slide the tube over the bundle. The same 1-inch rule in overall length applies. Leave an extra inch of tube hanging from the end. When shrunk, you can fold this extra plastic over on itself and hold in place with the electrical tape.