Dunbar 3635 Heat Shrink Tubing
The Dunbar 3635 is a flexible, flame retardant, 3:1 shrink ratio polyolefin heat shrink tubing engineered for reliable performance across a wide range of electrical and electronic applications. With the ability to shrink to one-third of its original diameter, the 3635 is the go-to solution for applications with large diameter variations — from wiring harnesses and connector bodies down to individual wire runs.
Electro Insulation Corporation is an authorized distributor of Dunbar heat shrink tubing and stocks the 3635 series in multiple sizes and colors. Whether you need a small quantity or a bulk spool order, we're here to help. For a full overview of our Dunbar product line, visit our Dunbar Heat Shrink Tubing page.
Dunbar 3635 Features & Specifications
The Dunbar 3635 is a single-wall, cross-linked polyolefin tubing built to meet demanding electrical insulation requirements. Its 3:1 shrink ratio sets it apart from standard 2:1 tubing, making it an excellent choice wherever a tight, conforming fit over irregular or stepped geometries is needed.
Key Features:
- 3:1 Shrink Ratio — Shrinks radially to 67% or more of its original diameter
- Material: Cross-linked polyolefin
- Wall Type: Single-wall (no adhesive); see 3635W for the adhesive-lined dual-wall variant
- Minimum Shrink Temperature: 90°C (194°F)
- Operating Temperature Range: −55°C to +110°C (−67°F to +230°F)
- Flame Retardant: Passes ASTM D2671
- Dielectric Strength: Min. 500 V/mil (ASTM D2671)
- Volume Resistivity: Min. 10¹⁴ Ω·cm (ASTM D876)
- Water Absorption: Max. 0.5% (ASTM D570)
- Copper Corrosion Resistance: No corrosion at 175°C/16 hrs
- Fungus Resistance: No growth (ASTM G21)
- RoHS & REACH Compliant
- Shelf Life: 10 years
The Dunbar 3635W variant shares the same 3:1 shrink ratio but features an inner adhesive lining that flows upon heating to create a moisture-resistant environmental seal — ideal for connectors, splices, and breakout points exposed to moisture or harsh environments.
Dunbar 3635 Technical Data Sheet
Download the full Dunbar 3635 spec sheet for complete technical data, test standards, and ordering information.
Available Sizes & Colors
Dunbar 3635 heat shrink tubing is stocked in a broad range of expanded internal diameters to fit virtually any wire, cable, or connector size.
| Size | Expanded Internal Diameter | Recovered Internal Diameter (Max) | Min. Wall Thickness | |||
|---|---|---|---|---|---|---|
| in | mm | in | mm | in | mm | |
| 1/16" | 0.063 | 1.6 | 0.021 | 0.5 | 0.015 | 0.4 |
| 3/32" | 0.093 | 2.4 | 0.031 | 0.8 | 0.015 | 0.4 |
| 1/8" | 0.125 | 3.2 | 0.047 | 1.2 | 0.015 | 0.4 |
| 3/16" | 0.187 | 4.8 | 0.063 | 1.6 | 0.020 | 0.5 |
| 1/4" | 0.250 | 6.4 | 0.084 | 2.1 | 0.020 | 0.5 |
| 3/8" | 0.375 | 9.5 | 0.126 | 3.2 | 0.025 | 0.6 |
| 1/2" | 0.500 | 12.7 | 0.168 | 4.3 | 0.025 | 0.6 |
| 3/4" | 0.750 | 19.1 | 0.252 | 6.4 | 0.030 | 0.8 |
| 1" | 1.000 | 25.4 | 0.336 | 8.5 | 0.035 | 0.9 |
| 1-1/4" | 1.250 | 31.8 | 0.420 | 10.7 | 0.040 | 1.0 |
| 1-1/2" | 1.500 | 38.1 | 0.504 | 12.8 | 0.045 | 1.1 |
| Black | Red | Blue | Yellow | White | Clear |
|---|---|---|---|---|---|
| ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
Not all sizes are available in every color. Contact Electro Insulation for specific size/color combinations or custom cut lengths. Our team can help you identify the right part number for your project.
Common Applications for Dunbar 3635 Tubing
The 3635's high shrink ratio, flame retardant polyolefin construction, and flexible body make it suitable for a wide range of industries and use cases:
- Wiring harness jacketing — Bundle and protect multi-conductor harnesses
- Connector-to-cable transitions — Neatly cover and strain-relieve connector bodies
- Wire splice insulation — Insulate and protect soldered or crimped splices
- Wire and cable identification — Use color-coded tubing for visual circuit management
- Component insulation — Sleeve exposed terminals, resistors, and other components
- Strain relief — Reinforce cable entry points to prevent flex fatigue and breakage
- Light-duty cable jacketing — Add an abrasion-resistant outer layer to cable assemblies
Industries and sectors that commonly specify Dunbar 3635 include aerospace, automotive, defense, telecommunications, industrial manufacturing, and consumer electronics.
For the full Dunbar product catalog and to download spec sheets, visit our Dunbar Heat Shrink Tubing page.