Heat-Shrink Tubing: Sizing

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0:00 – Heat-Shrink tubing is as simple as the name suggests.  When heat is applied, it shrinks.  Heat-shrink tubing is great for protecting cable connections, binding wires and cables together, and can be used in various different applications like automotive, audio and video, communications and the military.

00:28 – Unfortunately, choosing the size you need isn’t as straight forward.  You need to fully understand the product and get the right measurements before you can choose the size.

00:37 – 2 to 1, 3 to 1, 50%, 20% shrinkage… What does that even mean?

00:46 – If you see a “number to number” ratio, like 2 to 1, that means that the tube will shrink half of its diameter when heated.  The higher the first number, the greater the shrinkage.

00:59 – Although calipers are the most accurate, there are specialty devices available for measuring heat-shrink sizes or even a ruler will work just fine.

1:07 – Getting the right measurement is key when working with heat-shrink.  If you get the wrong size, the tubing could be too loose and slide off.

1:13 – To get the accurate size, measure the diameter of the thinnest part that the tube will be covering.  Expand the calipers and place whatever you’re measuring inside.  Then contract the calipers.  Read the measurement and make a note of it.  To make it easier for the tubing to slide over the cable, select tubing that has an Expanded Diameter that is 20 to 30 percent larger than your measurement. If you’re not using a caliper, lay your ruler over the top and read the diameter.  This is the size that you want the tubing to shrink down to, also called the Recovered Diameter.

1:46 – If you have any connectors to cover, measure the diameter of the biggest obstruction.   Choose tubing with an Expanded Diameter that is 20 to 30% larger than this number.

1:56 – Before you can order your heat-shrink, there is one other measurement that you need and that’s length.  Heat-shrink typically comes in packages of 6 inch or 4 foot pieces or in bulk by the foot.  Keep in mind that your tubing will shrink in length, so order enough to compensate. 

2:10 – A Value-Added Manufacturer, like Allied Wire & Cable, can cut your tubing to any length you need, and even print serial numbers, logos and special designs on your tubing.

2:21 – Here is the tubing that matches the measurements for our cable here.  Let’s see how it fits…Perfect!  This is exactly the type of fit we’re looking for, and it’s all because we took the time to measure for the right size.

2:33 – Most of the well-known brand name manufacturers of heat-shrink, such as Alpha, Raychem, LG, 3M & Sumitomo, will list the dimensions you’ve just determined in their catalogs. Allied Wire & Cable is an authorized distributor of these brands as well as other cost-effective alternatives. 

2:50 – For more information about the products you’ve seen in this demo or any other heat-shrink products, contact Allied Wire & Cable today. Call 1-888-325-1788, or visit our website at www.awcwire.com.

Need heat shrink tubing? First, you need to know the size! In this video, we show you the proper way to measure for shrinkable tubing so there’s no more guesswork.

Most heat shrink tubing specs list a shrinkage ratio in one of two ways: #:# ratio, as in 2:1 or 3:1, or as a percentage. They mean the same thing: a 2:1 shrinkage ratio means a shrink percentage of 50%, 3:1 means the finished diameter will be just 30% of the expanded diameter. The higher the number in the ratio, the great the shrinkage.

To choose a shrinkable tubing size, you need to take some measurements: the diameter of the smallest part you’re covering and the diameter of the widest part. By knowing how big the heat shrinkable tubing has to be to start, you can choose how big the tubing has to be at its expanded diameter. Then, you need to choose tubing that will successfully slide onto your material and shrink down enough for a snug fit. That is where the smaller measurement comes in handy.

If you don’t measure properly, your heat shrink tubing could slide off if it’s too big or rip if it’s too tight. The best way to measure is with a caliper, but if you don’t have one a ruler works just fine. Just make sure you lay the ruler over the material and measure just the diameter. Don’t use a flexible tape measure and take the circumference!

Once you have the diameter measurements, check out the sizes of the heat shrinkable tubing you want to purchase and choose one that is 20%-30% larger than the biggest measurement you took. This could be a connector, or your two measurements might be the same if you’re simply covering a splice. After you select the proper heat shrink tubing size, make sure you order enough length to cover your project. Most manufacturers and suppliers will enforce minimums if you only need a small amount, but if you have a big project don’t order too little. Some tubing shrinks longitudinally, so make sure to get a little extra.

For more information about the products you’ve seen in this demo or any other heat shrink products, contact Allied Wire & Cable today. Call 1-888-325-1788, or visit our website at www.awcwire.com.