Gamma Electronics Blog

What is Cold Shrink Tubing?

by | Jun 29, 2021 | Cable Protection, Gamma Electronics, Telecommunications, WISP | 0 comments

Most people are familiar with heat shrink tubing but many have not heard of cold shrink tubing.  So what is cold shrink and when and where does it get used?

We answer these questions and more below.

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What is Cold Shrink?

Cold Shrink is a rubber tube or sleeve that can shrink down many times smaller than its original size.  Unlike heat shrink it does not require any type of heat in order to shrink in size, which is what earned it the name “cold shrink.”   If you’re familiar with heat shrink don’t let the “cold shrink” name confuse you.  Heat shrink requires heat to shrink but cold shrink does not require cold to shrink.  The term “cold” is simply used to reference that no heat is required.

Gamma Electronics cold shrink ratio

Watch “What is Cold Shrink?”

How Does Cold Shrink, Shrink?

Cold Shrink Tubing wants to shrink down but it is held in place by an inner, plastic core, that keeps it from doing so.  That plastic core is perforated, with a piece of the tube ready to pull, (we call this piece the rip cord), to make removing it very easy.  As soon as you start to pull the inner core out of the way the tubing immediately shrinks.

Below is an example of the before and after sizing of one of our models of cold shrink tubing.  On the left side of the image is the “before”, or the pre-shrunk version of the cold shrink, with the plastic core in place.  That core is removed in the “after” portion of the photo, (shown on the right), where you can see the size the tubing has shrunk down to.

How Do I Install Cold Shrink?

Cold shrink tubing is incredibly easy to install and can typically be installed in less than a minute.  We made a step-by-step guide for those who are new to cold shrink installation, as well as a short video, (below), where we install cold shrink on an RF coaxial cable/conneciton to make it as clear as possible.

What is Cold Shrink Made Of?

Cold Shrink is typically manufactured from one of two types of rubber: EPDM or Silicone.  You can easily find cold shrink manufactured from both materials and they both have their perks.  EPDM tends to be more rugged and capable of taking a beating, making it ideal for when the cold shrink is likely to be in contact with other materials, like inside machinery for example.  Silicone on the other hand will shrink down to a much smaller and tighter size than EPDM, and is ideal for applications like cell tower weatherproofing.

We have an entire post dedicated to the differences between EPDM and Silicone Cold Shrink, which you can read here.

Where Would I Use Cold Shrink Tubing?

One of the most popular uses for cold shrink is on cell phone towers, where it is used to protect electrical cables/connections from water ingress and weather in general.  Cold shrink tubing is also used for various types of cable protection including splicing joints, cable trench applications, and in very confined or dangerous spaces where heat guns and/or blow torches are more difficult to use.  Cold shrink tubing is very popular in the telecommunications market, as well as in the oil, energy, cable television, satellite, and WISP industries.

What are the Key Benefits of Cold Shrink Tubing?

There are many key reasons that someone should choose cold shrink over other options.  We identify 7 of those reasons below.

1.  Incredible Sealing Properties

Cold Shrink Tubing, and specifically silicone cold shrink, offers incredible shrink ratios that make it easy to seal cables and/or connections from the outside elements.  The high shrink ratios make it so that the cold shrink can get around cables and connections and still seal down tight to not allow anything, water, dust, or otherwise, into the cable and/or connection.

2.  Fast & Easy Installation

Cold Shrink can literally be installed in seconds, and it creates a watertight seal while doing so.  Solutions like tape & butyl might be able to create a watertight seal, (initially), but it can take anywhere from five to twenty minutes to install per connection.  We did a time analysis which highlights the time cold shrink saves you versus tape and butyl, check it out here.

Similarly, cold shrink is much faster, (and safer), to install when compared to heat shrink as well.  Because Cold Shrink does not require a heat gun and/or blow torch it means installation becomes much faster, easier, and (again), safer.

3.  No Tools Required for Installation

This is similar to the last point, but we felt it was worthy to be mentioned on its own.  No tools means that there’s no additional tool cost when you choose to go with cold shrink.  It also massively reduces the hassle and cost of having to make sure you have batteries charged for heat guns, or propane/gas for blow torches.

4.  Cold Shrink is Safer

We have spoken to numerous companies who have made the switch to cold shrink tubing specifically because of how much safer it is, specifically in high fire danger areas.  Too often fires have been started by contractors who didn’t have a choice but to use heat guns and/or blow torches in high fire danger areas.  Cold Shrink tubing eliminates the need for those tools to be used in those areas.

Cold Shrink also has a far higher voltage rating than heat shrink tubing, which makes it a much-improved form of cable protection against power surges and arcing.

5.  Longevity

Cold Shrink tubing will outlast nearly all other forms of weatherproofing.  The tape and butyl method of weatherproofing, for example, is unlikely to last more than a year as it is unable to handle both high and low temperatures.  Butyl specifically is likely to melt in high temperatures and become brittle in lower temperatures. The adhesive on tapes will also not hold up to high and low temperatures, resulting in the tape coming loose over time.

Silicone cold shrink has incredible temperature resistance, going as low as -76° Fahrenheit, (-60° Celsius), and up to 446°  Fahrenheit, (230° Celsius), before showing signs of degradation.  In other words, you don’t have to worry about the cold shrink coming loose in either extreme hot or cold, in large part thanks to the fact that it has no adhesive, (more on that below).

Silicone cold shrink also comes with all the incredible properties that silicone offers in terms of weather protection, including UV resistance, and protection against Ozone and fungus.  We are so confident about the abilities of our silicone cold shrink that we guarantee it for the life of the cable.

6.  No Adhesive

When it comes to outdoor weatherproofing you typically want to avoid adhesive as a rule, which is one of the many reasons cold shrink tubing is such a fantastic weatherproofing option.  As mentioned previously, adhesives tend to melt in hotter weather, and they can prove ineffective in colder weather.  In other words, adhesive in weatherproofing can easily lead to your weatherproofing not working the way it should.  Adhesive can also melt and work its way into connections, causing issues in your cables.  At that point your weatherproofing is more problematic than it is helpful.

The other reason however, for mentioning the lack of adhesive being a great cold shrink feature is because it means removing cold shrink is far cleaner and easier than it is to remove tape or adhesive lined heat shrink.  If you want to remove weatherproofing from a connection and not have to replace the connection, then you should probably go with a solution like cold shrink.

7. Quality Control

A key benefit that customers like AT&T have told us, is that cold shrink tubing makes it easy to ensure consistent installation results.  Experienced and inexperienced installers alike can get the same results with Gamma Cold Shrink Tubing, which becomes especially important when a single location can require dozens upon dozens of connections needing weather protection.

Does Cold Shrink Come in Different Sizes?

Yes, absolutely.  In our cold shrink sizing chart, (below), you can see the model of cold shrink we have matched with various cable and connector combinations.  We have tested our cold shrink with these various combinations to ensure that they are watertight, with IP68 rated weather protection.

Each model of cold shrink shown above has been designed for and tested with the connectors and cables shown in the chart.  We test by installing the cold shrink on a cable/connection and then dunking the cold shrink and connection into a water tank more than a meter deep.  After about 45 minutes to an hour we remove the cold shrink/connection from the tank and check for any signs of water getting into the connection.  All of the cold shrink models shown above have passed testing, numerous times, with the cable and connector combinations shown next to them.

What Does Shrink Ratio Mean?

Shrink Ratio refers to the size the cold shrink starts at compared to the size it shrinks down to.  This difference between where the cold shrink starts versus where it ends up is expressed mathematically in a ratio format.  For example, our SDL-1A-125 cold shrink tubing starts more than 4 times larger than what it ends up shrinking down to.  To make it easy we say it has a 4 to 1 shrink ratio, or 4:1, (technically it is closer to 4.5 to 1).

Most of our silicone cold shrink is around a 4 to 1 (4:1) shrink ratio, although some of our smaller cold shrink models are closer to around 3.5 to 1, (3.5:1).

Watch EPDM vs Silicone Cold Shrink: Shrink Ratio Comparison

Does All Cold Shrink Tubing Shrink Down to the Same Size?

No.  Different models of cold shrink tubing have different shrink ratios.  Each model of cold shrink tubing shrinks down to a unique size and you will want to make sure that you have the right model that starts large enough to get around your cable, connector, etc., and is still able to shrink down small enough to give you the watertight seal you need.  In our cold shrink sizing chart you can see the cold shrink models that we have tested and that we recommend to match with popular cable and connector combinations.

Below we have images of two of our models of cold shrink, to demonstrate the contrast.  The SDL-1A-125 is larger with a higher shrink ratio, while the SDL-SMA-60 is smaller with a still very impressive 3:1 shrink ratio, (click on the photos to enlarge).

SDL-SMA-60 Dimensions

On our Silicone Cold Shrink page you can also find images like those above, where we show the exact dimensions that each of our cold shrink models start at, and shrink down to.  We made these graphics to make it easier for our customers to visualize if our cold shrink can work for the cable, connector, etc. that they are trying to protect.

How Do I Choose the Right Size Cold Shrink?

There are three things to consider when trying to choose the right cold shrink size, (in no particular order): the starting size, (or pre-shrink size), the length, and the shrunk down size of the cold shrink.

You can start by looking at the largest thing that the cold shrink needs to fit over, (usually the connector).  You need to make sure the cold shrink starting size can fit over that size, plus a little bit of wiggle room for the plastic core of the cold shrink to have enough room to be removed.  If the fit between the cold shrink and the connector, cable, or whatever you’re trying to protect, is too tight, then the inner core won’t be able to be removed and you won’t be able to install the cold shrink.

Next, make sure the cold shrink is long enough to fully cover what you want protected, plus a little extra.  You don’t want the cold shrink tubing to be too short in case you miss the mark ever so slightly.

Lastly, you need to make sure the cold shrink can shrink down small and tight enough to create a water tight seal.  For example, our SDL-1A-125 model shrinks down to 0.4 inches, making it ideal for shrinking onto half inch, (0.5″), cables.  The fact that the SDL-1A-125 will shrink down smaller than 0.5 inches mean you get an even tighter seal with your cold shrink on half inch cables.

If you’re unsure about what size cold shrink tubing you might need feel free to Contact Us, and a member of the Gamma team will gladly help you find the right model for your application.

Can You Make Cold Shrink in Custom Sizes?

Absolutely.  We have made custom sized cold shrink for varying customers and we can make it in different colors, (including clear).  If you need custom sized cold shrink just reach out to our sales team and they will help figure out the specifics.

Conclusion

Cold Shrink Tubing is an incredible cable protection tool that holds up better to weather and environmental factors than all of its competitors.  We consider silicone cold shrink tubing to be the ultimate outdoor, “set it and forget it” weatherproofing solution.  We also have customers using it indoors in very moist situations where other solutions just have not measuresd up.

Cold Shrink Tubing also has the added benefit of being far easier and safer to install than its competitors.  Say goodbye to heat guns, blow torches, while saying hello to higher voltage ratings and installation consistency.    Our customers have seen install times improve and maintenance costs go down when using Gamma Cold Shrink.  It is for these reasons that Gamma Silicone Cold Shrink has become a top choice for the telecommunications industry, as exemplified by AT&T approving 5 different models of Gamma Cold Shrink.

You will be hard pressed to find a better weatherproofing solution than Gamma Cold Shrink, and you will see the results almost immediately upon using it.

Try Gamma Cold Shrink

Ready to improve your weatherproofing?  Give Gamma Cold Shrink a shot.  Reach out to our sales team at (909) 860-1479, or Contact Us by clicking on the button below.

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