Tip 1: When shrinking heat shrink tubing it is advisable to start the shrinking process in the middle section of the tubing and then gradually proceed to one end and then from the middle again to the opposite end. This helps you avoid trapping air under the tubing.
Tip 2: Tubes also shrinks longitudinally i.e. along its length. You should factor in this shrinkage when cutting the tubing into lengths.
Tip 3: It is possible to minimise the longitudinal shrink by shrinking the ends first and then the middle section. However, if you do this, air can get trapped, which will prevent the middle section from shrinking. Alternatively, you can shrink the tubing by starting at the most critical end and then shrinking down slowly towards the other end.
Tip 4: If the object to be covered is metal or heat conductive, care must be taken to ensure the object is pre-heated to avoid “cold spots” or “chill marks”. This ensures a tight and smooth fit of the tubing.
Tip 5: When cutting heat shrink tubing and wrap-around sleeves to the desired length, take special care to ensure that the ends are cut smoothly. Poorly cut and irregular edges can cause heat shrink tubing and sleeves to split during shrinkage.
Tip 6: When choosing the tubing size it is important to consider the 80:20 rule. This means the tubing size should be chosen to allow minimum shrinkage of 20 % and a maximum of 80 %. Detailed examples of how to select the right heat shrink tube are available in the insulation product section of our catalogue.
Tip 7: During shrinking you should always make sure that the workplace is well ventilated and that you wear personal protective equipment like gloves and safety glasses.
The material thickness should be indicated in mm after complete shrinking. "Nominal" defines dimensions without any tolerances. Generally, you can distinguish between thin wall, medium wall and thick wall. Heat shrinkable tubing is also available with an adhesive liner. This is also called dual wall tubing.
For thin wall tubing with a shrink ratio of 2:1 (standard tubing) the diameter is usually in inch sizes; 25.4 mm equals 1 inch.
Depending on the material compound used and wall thickness, heatshrink tubing can be extruded to a different degree. The shrink ratio indicates the rate that the product shrinks to (i.e. the supplied diameter in relation to the recovered diameter). It varies from 2:1 to 6:1. The higher the ratio, the greater the object diameter the tubing can cover. Thus, fewer sizes of tubes are needed, which helps to reduce stock levels.
Heat shrink tubing does not only shrink in diameter, but also in length. This longitudinal change after shrinking is indicated in a percentage.
Minimum shrinkage temperature:
Not all tubes shrink at the same temperature. It strongly depends on the type of compound they are made from and also the wall thickness.
The operating temperature varies per tubing type. This is dependent on the compound used for the tubing type. When selecting the correct size, it is recommended to follow the 80:20 rule outlined above.
Heat shrink tubing is used in cable harness assembly in general. This includes insulation, identification, and mechanical protection against abrasion as well aesthetical design.