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Wiring Fundamentals: Dual Wall Heatshrink

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Dual Wall Heatshrink

01.45

00:00 - Dual wall heat shrink, more commonly called glue shrink, is a particular type of heat shrink that has an inner lining which melts as heat is applied and it recovers to its smaller size.
00:09 Once the heat shrink cools, this lining solidifies again, sealing the heat shrink onto whatever it is in contact with.
00:16 Most commonly this heat shrink is used to seal and support harness branch points and connector terminations.
00:23 When we're using braided sheathing it keeps the cut ends together to keep them from fraying.
00:28 There are two common types of dual wall shrink I use.
00:30 They're both Raychem products.
00:32 One is ATUM and the other SCL.
00:35 ATUM has a high shrink ratio of 4:1 making it easy to install over branched sections.
00:41 Its inner glue lining is a lot like tradition hot glue in that it retains some flexibility in its cooled state.
00:47 This glue shrink can be very useful in an application that requires that flexibility.
00:52 More often though I find myself using Raychem SCL glue shrink.
00:56 It has a slightly lower shrink ratio of 3:1 but it becomes very rigid when it cools and provides excellent strain relief.
01:03 The inner lining is a black potting compound that is more robust and seals better than the lining used in ATUM.
01:10 SCL is particularly useful for creating connector sealing boots as it's very tidy once installed and can be manipulated while still hot to permanently set the angle at which the wiring harness meets the connector.
01:22 Regardless of which dual wall shrink you use and what application you're using it for, you must thoroughly abrade the surface the dual wall shrink will recover onto with 150 grit emory paper to ensure a reliable bond.