Sapphire Energy
Marine Grade 3:1 Adhesive Heat Shrink
Marine Grade 3:1 Adhesive Heat Shrink
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Professional-grade dual-wall heat shrink with an internal adhesive lining for sealing crimped lugs and wiring connections. When heated, the tubing shrinks tight and the adhesive flows to fill cracks and create a moisture-proof seal — a clean, durable finish for battery cables and DC wiring.
The 3:1 shrink ratio gives you lots of flexibility with the sizes it fits. Easily sliding over large lugs and still shrinking down to a small wire.
- 3:1 shrink ratio — wide enough to slide over lugs, shrinks tight for a clean finish
- Dual wall + adhesive lined — helps seal out moisture and reduce corrosion
- Marine-grade style sealing — ideal for mobile, marine, and harsh environments
- Easy to use — just slide on and heat
- Extra mechanical protection for cables passing through firewalls, boards, panels, and bulkheads
| Shrink Ratio | 3:1 |
|---|---|
| Construction | Dual wall (polyolefin outer with adhesive inner liner) |
| Adhesive Lined | Yes (heat-activated) |
| Use Case | Sealing lugs, terminations, splices, plus added abrasion / moisture protection |
| Sold As | Per foot, cut length |
Recovered diameters below are a practical guide for fully-shrunk tubing. Actual results vary with heating method, substrate shape, and wall thickness.
| Variant Size (I.D.) | Recovered Diameter (Approx.) |
|---|---|
| 1" (25.4 mm) | ~1/3" (8.5 mm) |
| 3/4" (19.1 mm) | ~1/4" (6.4 mm) |
| 1/2" (12.7 mm) | ~1/6" (4.2 mm) |
| 3/8" (9.5 mm) | ~1/8" (3.2 mm) |
| 1/4" (6.4 mm) | ~5/64" (2.0 mm) |
For most crimped lug connections, customers typically use 2–3 inches of heat shrink per lug to cover the barrel and insulation transition.
Choose a size that will slide over the largest part of the connection before shrinking. On most battery cable lugs, that means sizing for the pad width, not just the barrel or cable insulation.
| Wire / Lug Size | Suggested Heat Shrink Size |
|---|---|
| 8 AWG | 3/8" – 1/2" |
| 6 AWG | 3/8" – 1/2" |
| 4 AWG | 1/2" |
| 2 AWG | 1/2" – 3/4" |
| 1 AWG | 3/4" |
| 1/0 (0 AWG) | 3/4" |
| 2/0 AWG | 3/4" – 1" |
| 4/0 AWG | 1" |
Note: Some lugs (especially wide pad styles) may require stepping up one size to fit over the barrel. Always confirm fit before crimping, and remember to slide the heat shrink onto the cable before crimping the lug if it is too small.
- Sold per foot
- Cut material is non-returnable
- For best results, use a heat gun and heat evenly until adhesive has visibly flowed at the ends
What makes this “marine grade” heat shrink?
It’s dual wall tubing with an internal adhesive liner. When heated, the adhesive flows and bonds to the cable/connector to help create a moisture-resistant seal.
Is this good for sealing crimped lugs on battery cables?
Yes — it’s ideal for covering the lug barrel and insulation transition after crimping. It helps reduce corrosion and gives a clean, professional finish.
Can I use heat shrink for abrasion or pass-through protection?
Yes — it’s a handy way to add extra mechanical protection where cables pass through panels, boards, bulkheads, or around sharp edges (in addition to proper grommets/strain relief where required).
How do I choose the right size?
Choose a size that will slide over the largest part of your connection (often the lug). Because it’s 3:1, it can shrink down tight over the cable insulation afterward. Use the sizing table above as a quick reference.
Does adhesive-lined heat shrink make a connection waterproof?
Adhesive-lined heat shrink is designed to create a moisture-proof seal when properly installed. For best results, heat evenly and ensure you see adhesive flow at both ends of the tubing.
How long is my piece going to be?
If you're only ordering a few feet, we usually ship as a single piece. If you're ordering larger quantities, it may ship cut into a few lengths (at least 1ft each).
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