KSV LOOMS · TECHNICAL GUIDE
ATUM and SCL both shrink around a joint and have an inner lining that flows when heated. ATUM provides an adhesive seal with a more flexible covering; SCL provides a semirigid covering with a meltable encapsulant. Choose for the joint, the surrounding materials, and the support your loom needs.
How the Inner Lining Works
ATUM’s adhesive melts and bonds to suitable surfaces as the outer tubing shrinks. SCL’s inner encapsulant melts and fills surface irregularities inside its semirigid outer wall. Both can protect splices, terminations, and cable transitions when correctly selected and installed.
Moisture resistance depends on fit, surface condition, material compatibility, and complete recovery. Tubing over a connector’s cable entry does not automatically make its mating interface waterproof.
ATUM vs SCL at a Glance
| Property | ATUM | SCL |
|---|---|---|
| Construction | Flexible, adhesive-lined dual wall | Semirigid, encapsulant-lined dual wall |
| Shrink ratio | 3:1 or 4:1, depending on size | 2.5:1 or 3:1, depending on size |
| Minimum shrink temperature | 80°C | 125°C |
| Minimum full recovery temperature | 110°C | 135°C |
| Continuous operating range | −55°C to +110°C | −55°C to +110°C |
Check the selected part’s dimensions and specification. The temperature needed to shrink tubing during installation is separate from its continuous operating limit.
What We Choose at KSV
For Tefzel M22759 looms, we often prefer SCL where a splice or transition needs a firmer protective covering. Its semirigid construction suits the support and crush protection we look for in those locations. It also makes that section less flexible, so consider where the harness will bend.
For TXL and other OEM automotive wire, ATUM is often our starting point when lower recovery heat and flexibility are useful. TXL uses cross-linked insulation; excessive installation heat can still damage the wire or nearby components.
Wire type alone does not decide the tubing. Check the complete assembly’s materials, heat tolerance, sealing needs, and desired stiffness. Tefzel’s heat resistance does not raise the finished tubing’s 110°C continuous operating limit.
Control the Heat and Check the Fit
The temperatures above describe the tubing, not a universal heat-gun setting. Follow the selected product’s installation guidance and apply controlled, even heat. Exposure time and local hot spots matter; a wire’s continuous temperature rating alone does not establish a suitable shrinking process.
Choose an expanded inside diameter that clears the largest part of the joint and a recovered size that grips the areas being sealed. Check wall thickness and finished length as well as shrink ratio. A larger ratio cannot compensate for an unsuitable size or a surface the lining does not seal against.
Why KSV Supplies 6-inch Sections
Our ATUM and SCL stick listings are priced per foot and normally supplied as two 6-inch pieces per foot ordered. One foot ordered is therefore not one continuous 12-inch piece.
We cut the factory sticks into shorter sections to keep packaging manageable and shipping costs down. Many splice and transition jobs only need a short piece. If you need an uncut 4-foot stick or another continuous length, contact us before ordering so we can confirm the available format.
Need Help Choosing Tubing?
Send the wire type, joint dimensions, and where it will be used. We can help choose the tubing and size for your loom or wiring harness.