Shrink Heat Tube

1. What is Shrink Heat Tube?

Shrink heat tube is mainly made of polyethylene polymer and can shrink uniformly when heated. It can tightly fit wires, soldering points, terminals and sensors, providing effective insulation, moisture resistance, dust resistance, corrosion resistance and mechanical protection. As one of the most commonly used protective accessories in electronics, electrical, automotive and communication equipment, tube heat shrink is easy to operate — it shrinks and firmly wraps the target object simply by heating, therefore it is widely used for harness repair, joint sealing, equipment maintenance and electrical insulation protection.

2. Structural Classification of Heat Shrink Tube (by structure and shrink ratio)

1. 2:1 Single-wall shrink heat tube (standard type)

Structure: Single-layer polyethylene material

Shrink ratio: 2:1 (radial shrink about 50% after heating)

Characteristics: Soft texture, excellent electrical insulation performance, the most widely used type

Typical uses: General wire repair, insulation of electronic solder joints, cable bundling and marking, terminal color coding

Advantages: Economical, practical, easy to operate, highly versatile

2. 3:1 Dual-wall adhesive heat-shrink tube

Structure: Composed of outer polyethylene layer and inner hot-melt adhesive layer

Shrink ratio: 3:1 (after shrinking the size is about 33% of the original diameter)

Characteristics: Hot-melt adhesive fills gaps when heated, achieving effective sealing and providing moisture and dust protection

Typical uses: Automotive harness protection, outdoor lighting connection sealing, instrument connectors, waterproof terminals

Advantages: Adapts to irregular shapes, high sealing integrity

3. 4:1 Dual-wall adhesive heat shrinking tubes (high-shrink sealing type)

Structure: Outer polyethylene layer combined with thicker inner hot-melt adhesive layer

Shrink ratio: 4:1 (radial shrink can reach more than 75%)

Characteristics: Suitable for joints with larger size differences, sealing protection level close to IP67

Typical uses: Marine electrical systems, battery pack connections, solar installations, industrial equipment cables, motor circuit repair

Advantages: Excellent weather resistance, impact resistance and waterproof performance, meeting heavy industrial environment requirements

3. Comparison Table of Different Structural Shrink Heat Tubes

Category item	2:1 Single-wall heat shrink cable tube	3:1 heat shrink plastic tube	4:1 heat shrinking tube
Construction	Single-layer polyethylene	Outer polyethylene + inner hot-melt adhesive	Outer polyethylene + thicker inner hot-melt adhesive
Shrink capability	Medium (about 50%)	High (about 67%)	Very high (75%+)
Fit	Basic fit	Tight fit (adhesive fills gaps)	Extremely tight fit (adapts to large size differences)
Waterproof performance	None	Strong waterproof sealing	Very strong waterproof sealing (near IP67)
Flexibility	Softest	Moderate	Slightly stiff
Weather/Chemical resistance	Moderate	Good	Best (industrial grade)
Difficulty of use	Lowest	Medium (requires even heating)	Slightly higher (requires careful heating)
Typical uses	Wire repair, solder joint protection	Automotive harnesses, waterproof connectors	Marine, solar, battery packs, etc.
Cost level	★ (lowest)	★★★	★★★★ (highest)
Customer selection rate	Highest (general purpose)	High (waterproof needs)	Professional fields (high requirements)

4. Technical parameters and specification table of 2:1 single-wall Shrink Heat Tube

Technical Parameters

• <strong>Heat shrink tube material: Polyethylene
• Colors: Black, White, Red, Yellow, Blue, Green
• Shrink temperature: Start at 100℃, fully shrink at 110℃
• Elongation at break: ≥300%
• Working voltage: 1000V
• Tensile strength: >12MPA

<h3>heat shrink tube sizes (2:1 shrink single-wall)

Model (mm)	Actual inner diameter (mm)	Shoulder width (mm)	Wall thickness before shrink (mm)	Wall thickness after shrink (mm)	Length per roll (m / roll)
1 mm	1.5 ± 0.2	–	0.185 ± 0.03	0.37 ± 0.05	200
2 mm	2.5 ± 0.2	–	0.19 ± 0.03	0.38 ± 0.05	200
3 mm	3.5 ± 0.2	–	0.20 ± 0.03	0.40 ± 0.05	200
4 mm	4.5 ± 0.3	–	0.21 ± 0.03	0.42 ± 0.05	200
5 mm	5.5 ± 0.4	–	0.22 ± 0.03	0.42 ± 0.05	100
6 mm	6.5 ± 0.4	–	0.22 ± 0.05	0.42 ± 0.05	100
8 mm	8.5 ± 0.5	13.7	0.21 ± 0.03	0.42 ± 0.05	100
10 mm	10.5 ± 0.5	17.3	0.24 ± 0.03	0.48 ± 0.05	100
12 mm	12.5 ± 0.5	20	0.25 ± 0.03	0.50 ± 0.05	100
14 mm	14.5 ± 0.5	23.3	0.26 ± 0.04	0.52 ± 0.07	100
16 mm	16.5 ± 0.5	26.8	0.29 ± 0.04	0.58 ± 0.07	100
18 mm	19.0 ± 0.5	29.7	0.29 ± 0.04	0.60 ± 0.07	100
20 mm	21.0 ± 0.5	33.5	0.31 ± 0.04	0.62 ± 0.07	100
22 mm	23.0 ± 0.5	35.3	0.32 ± 0.04	0.65 ± 0.07	100
25 mm	26.0 ± 0.5	41	0.35 ± 0.04	0.70 ± 0.07	25
30 mm	31.5 ± 0.5	48.7	0.39 ± 0.04	0.78 ± 0.07	25
35 mm	36.5 ± 1.0	56.3	0.39 ± 0.05	0.78 ± 0.07	25
40 mm	41.5 ± 1.0	65	0.39 ± 0.05	0.78 ± 0.07	25
50 mm	≥50	81.3	0.41 ± 0.05	0.80 ± 0.10	25
60 mm	≥60	95.2	0.42 ± 0.05	0.86 ± 0.10	25
70 mm	≥70	111.7	0.43 ± 0.05	0.88 ± 0.10	25
80 mm	≥80	126.1	0.45 ± 0.05	0.90 ± 0.10	25
90 mm	≥90	140.5	0.50 ± 0.05	1.00 ± 0.10	25
100 mm	≥100	157.1	0.55 ± 0.05	1.10 ± 0.10	25

<p>heat shrink tube size chart

5. Heat Shrink Sleeve Application​

Electronic circuit insulation

In electrical wiring and component protection, using heat shrink tube for wires for insulating joints can effectively prevent short circuits and ensure long-term stability and safety of internal circuits.

Automotive harness protection

Electric wire heat shrink tube provides wear-resistant, waterproof and oil-resistant sealing protection for automotive cable joints, ensuring that vehicle circuits can operate reliably under various complex road conditions and environments.

Lithium battery safety packaging

In lithium battery pack assembly, heat shrink tubes are key insulating materials, providing professional insulation wrapping for battery cell electrodes and fundamentally eliminating short-circuit risks.

Cable identification and management

With numbered heat tube shrink, clear and permanent labeling can be achieved while shrinking and fixing cables, greatly facilitating system maintenance and troubleshooting.

Metal structure corrosion protection

Applying heating shrink tube to metal welds or structural components forms a dense protective layer that isolates moisture and corrosive substances, significantly extending the service life of metal parts.

6. Correct usage method (steps)

Selection and measurement

First, based on the size of the cable or component, choose a shrink Heat tube with a suitable inner diameter. Usually, the pre-shrink inner diameter should be about 25% to 50% larger than the diameter of the object to ensure easy installation.

Cutting and preparation

Use clean scissors or wire strippers to cut the cable protector heat shrink tube to the required length. The cut should be smooth and burr-free to ensure a neat appearance and uniform sealing after shrinking.

Sliding on and positioning

Before connecting or soldering any component, always slide the electrical heat shrink tube onto one end of the cable. This is often overlooked but is a crucial step; after completing the connection, position the tube over the joint.

Even heating and shrinking

Use a shrink tube heat gun or professional heating tool, starting from the middle of the shrink heat tube and moving the heat source back and forth evenly so that it shrinks uniformly in the radial direction. Then move slowly toward one or both ends until the tube wall fits tightly.

Completion and inspection

After heating, allow it to cool naturally. Check whether the surface is smooth and free of burn marks or bubbles, and confirm that it is fully adhered to the protected object, forming a uniform and reliable insulating protective layer.

7. FAQ Frequently Asked Questions