Heat Shrink – Complete Guide
This guide explains what heat shrink tubing is, how it works, where to use it, how to choose the right material and shrink ratio, and how to get the best results when applying it.
1. What is Heat Shrink Tubing?
Heat shrink tubing is a thermoplastic tube that shrinks in diameter when heat is applied. It’s used to insulate wires, provide abrasion resistance, seal connections, and offer strain relief. Once heated, it contracts to form a tight, protective layer over the material underneath.
2. Common Applications
Heat shrink is widely used in electrical, automotive, marine, aerospace, and industrial settings. Applications include wire insulation, cable bundling, environmental sealing, colour coding, mechanical protection, and waterproofing.
3. Shrink Ratios Explained
Shrink ratio refers to how much the tubing will shrink. A 2:1 ratio means it will shrink to half its original diameter. For irregular shapes or tighter seals, higher ratios like 3:1 or 4:1 may be needed.
4. Material Options
The most common material is polyolefin, which offers flexibility and good insulation. Other options include PVC, PTFE, elastomers, and fluoropolymers—each suited to different temperature, chemical, and environmental conditions.
5. Single Wall vs Dual Wall
Single wall tubing provides basic insulation and abrasion protection. Dual wall tubing includes an adhesive lining that melts during heating to create a seal, ideal for waterproofing and high-reliability environments.
6. Installation Tips
Use a heat gun or controlled heat source to shrink tubing evenly. Start from the centre and move outward to prevent air pockets. Avoid open flames and overheating. Ensure tubing is the correct size and allows for 5–10% length reduction.
7. Mistakes to Avoid
Don’t use oversized tubing—it won’t shrink tightly. Avoid underheating, which leaves loose sleeves, or overheating, which may damage the tubing. Always check material specs for temperature limits and environmental compatibility.
