What Is Heat Shrink Tubing?
Heat shrink tubing is a plastic tube that, when heated, shrinks in diameter to wrap around, insulate and mechanically protect the cable joint it's slid over.
How Does It Work?
It's a special plastic expanded during manufacture. When heat (a hot-air gun, a lighter) is applied it shrinks back to its "remembered" small diameter and wraps the cable tightly.
Shrink Ratio
Tubing is referred to by its shrink ratio (like 2:1, 3:1). A 2:1 ratio means the diameter halves when heated. To slide it on, the initial diameter must be larger than the cable and the shrunk diameter smaller than the cable.
| Property | Value |
|---|---|
| Shrink ratio | 2:1 / 3:1 |
| Application | Hot air / heat |
| Function | Insulation + mechanical protection |
Where Is It Used?
Soldered cable joints, connector terminals, gathering a cable bundle, repair and insulating exposed conductors.
Correct Application
The tubing is slid onto the joint area beforehand (you can't slide it on afterward), then slid over and heated after the joint is made. The heat must be distributed evenly; excessive/spot heat burns or holes the tubing.
Adhesive (Dual-Wall) Type
Some tubing has a layer of adhesive on its inner surface that melts when heated. As it shrinks this adhesive wraps the cable and forms a watertight (IP-rated) seal. The adhesive type is preferred for outdoor, automotive and damp-environment connections.
Common Mistakes
- Forgetting to slide it on first: the tubing won't go on after the joint is made.
- Excessive heat: too much heat on one spot burns/holes the tubing.
- Wrong diameter: tubing too large doesn't wrap tightly even when shrunk.
Frequently Asked Questions
Why tubing instead of tape?+
What is it heated with?+
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