Raychem SCL Heat Shrink

Raychem SCL — Dual-Wall Adhesive Heat Shrink, 20 cm Sticks

Raychem SCL is a dual-wall heat shrink tubing with a meltable adhesive inner liner. When heated, the outer wall shrinks at a 3:1 ratio while the inner liner flows to fill voids and bond to the wire or substrate, forming a moisture-tight, electrically insulating seal. SCL is used wherever a connection must be protected from water ingress, fluid contamination, or corrosion — splice joints, harness breakout points, and connector strain relief.

Sold in 20 cm pre-cut sticks. Each unit ordered is one 20 cm stick. This format eliminates the need for a reel or dispenser and is convenient for bench assembly.

SCL is black, unaffected by most solvents and chemicals, and can be pinched while still hot to close a harness branch opening — the adhesive seals the pinched point without additional sealant compound.

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Size Range

Size	ID supplied	ID recovered	SKU
1/8″	3.2 mm	0.6 mm	SCL-1/8
3/16″	4.7 mm	1.5 mm	SCL-3/16
1/4″	6.4 mm	2.0 mm	SCL-1/4
3/8″	9.5 mm	3.4 mm	SCL-3/8
1/2″	12.7 mm	5.0 mm	SCL-1/2

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Technical Specifications

Property	Value
Manufacturer	Raychem
Wall type	Dual wall with meltable adhesive inner liner
Colour	Black
Shrink ratio	3:1
Installation temperature	135 °C
Adhesive inner liner	Yes
Flame retardant	No
Sold as	20 cm stick (one stick per unit ordered)

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FAQ

What is the difference between SCL and standard heat shrink?

Standard single-wall heat shrink provides mechanical protection and strain relief, but leaves the tube ends open — moisture can enter from either end. SCL has a meltable adhesive inner liner that flows when heated and bonds to the wire insulation, sealing both ends and filling any gaps. The result is a moisture-tight sleeve without any additional sealing compound. Use standard heat shrink where sealing is not required; use SCL where the joint must resist water, humidity, or fluid.

Why is SCL sold in 20 cm sticks rather than on a reel?

Motorsport harness builders typically need one or two sticks per splice point and do not consume large quantities of a single size continuously. Pre-cut 20 cm sticks eliminate waste and make it simple to grab the right quantity without measuring and cutting from a reel. Each stick is long enough to cover the typical splice or termination with overlap to spare.

Can SCL be used to form a harness breakout?

Yes. Apply a suitable SCL size over the breakout point and heat until the outer wall fully recovers. While the adhesive is still hot and fluid, pinch the tube closed at the branch opening with pliers. The adhesive seals the pinched point. Allow to cool before releasing. This technique works on two-wire and three-wire breakouts without requiring a moulded boot or T-connector.