Gamma Electronics Blog

What is Self-Amalgamating Tape (Magic Tape)?

by | Aug 14, 2019 | Cable Protection, RF Weatherproofing | 0 comments

What is Self-Amalgamating Tape?

What is Self-Amalgamating Tape?

Self-Amalgamating tape is a rubber tape that can adhere to itself without heat or glue/adhesive. It is non-tacky, and its unique and simple installation is what often earns it nicknames like “Magic Tape,” “self-fusing tape,” “self-vulcanizing,” or even “cold shrink tape.”

Self-Amalgamating tape works by pulling and stretching the tape so that as you place the stretched-out layer of tape over another layer of itself, the two layers interweave or “self-amalgamate.”

What is Self-Amalgamating Tape?

What Does “Amalgamate” Mean?

It makes sense to use the word “amalgamate” when describing this type of tape.   “Amalgamate” is a verb that defines the meaning to be..

“to mix or merge so as to make a combination; blend; unite; combine.”

When discussing “amalgamate” in terms of self-amalgamating tape we’re talking about how two or ore layers of tape combine, blend, or unite to become one solid piece.

How Does Self-Amalgamating Tape Work?

Self-amalgamating tape uses a chemical bond that results in two layers of the tape becoming a permanent bond, (also called vulcanizing).  This is sometimes referred to as “cross-linking” and it happens on a molecular level.  The tape is very easy and pliable when you first work with it but once the bond has begun, and as it is given time to set in, it becomes permanent to the point that it becomes like a mold that has formed around whatever it was applied to.

In the photo below you can see a good example of how self-amalgamating tape forms around what it is protecting.  The photo shows a coaxial connector that had the tape applied to it, with the now removed/cut off tape next to it.

Self-Amalgamating Tape Cut off Coax Connector

What is Self-Amalgamating Tape Made Of?

Our self-amalgamating tape, (Magic Tape), is made of Ethylene Propylene Rubber which makes it incredibly similar to EPDM used in many weatherproofing applications, including roofing.  There are versions of self-amalgamating tape available in silicone and while we love silicone, Ethylene Propylene Rubber is more rugged and can better withstand the applications that many of our customers will often use Magic Tape for.  Especially because the tape is being pulled and stretched it is more susceptible to tearing.  Ethylene Propylene Rubber better withstands this type of use while still offering fantastic weatherproofing results.

A good example of this is in the marine/sailing market.  It is common in the marine/sailing world to use self-amalgamating tape as “rigging tape” that protects sails, (and more), from chafe and sharp protrusions.  In these instances, the tape is going to encounter a high amount of abrasion, and silicone self-amalgamating tape will not hold up in such conditions.

Unfortunately, silicone is not ideal for any type of self-amalgamating tape that may need to tightly wrap around something irregular or protruding. The fact that self-amalgamating tape needs to be stretched means that silicone-based tape will have very little tear resistance.  Silicone does however have a higher voltage rating than Ethylene Propylene Rubber.

How to Install Self-Amalgamating Tape

No gloves or special tools are required to install self-amalgamating tape.  The only thing(s) you will need are scissors or a blade to cut the tape to your needed length.

To keep the tape from adhering to itself Magic Tape comes with a protective, plastic peel-away layer that allows the tape to be rolled and shipped.  To install the tape, you peel away a portion of this protective plastic layer, pull to stretch the portion of tape you intend to use, and wrap it around what you are attempting to protect.  You then take another portion of the tape, pull to stretch it, and wrap it so that about half of it is overlapping the previous layer.  Pulling the tape as you install it not only creates a tighter wrap but, more importantly, it helps the tape better amalgamate/adhere to itself as you wrap it.

It’s important to wrap the cable onto itself and typically, best practice is to wrap the tape over itself by 50%, meaning that once you wrap your first layer your second layer should overlap about half (or 50%) of the first layer, and so on. This 50% rule ensures that you get a strong bond between the different layers of tape that properly adhere to one another.  This is also the reason that some self-amalgamating tape comes with a line down the center, to help serve as a guide as how to layer the tape over itself.

How Long Does Self-Amalgamating Tape Take to Set?

It only takes a few minutes for the bond between the two tape layers (or more) to amalgamate.  Your wrap does not have to be perfect the first time you apply it, but you will want to make any necessary corrections to how you wrapped it very quickly, before the bond sets in.  You will also want to make sure you have a tight, overlapping wrap/installation to ensure you get the best results from the tape.

How Long Does Self-Amalgamating Tape Last?

Self-amalgamating tape will last years or even decades.  Our self-amalgamating tape is made from ethylene propylene rubber which is incredibly resistant to weather, heat, UV, oxidation, and ozone.  Self-amalgamating tape also avoids the issues that come with adhesives, which do not hold up well in hot or cold temperatures.

Silicone-based self-amalgamating tape has incredible weather resistant properties as well, but, (as previously noted), it is more susceptible to tearing when used as a tape.

How Do You Remove Self-Amalgamating Tape?

Because it has no adhesive, self-amalgamating tape can be easily removed with a blade, like a box cutter.  It is possible that you could cut what is underneath the tape in the process however.

Is Self-Amalgamating Tape the Same as Weatherproof Tape?

Not technically, no.  Even though Self-amalgamating tape is used for weatherproofing, most tape that goes by the name of “weatherproofing tape” tends to have adhesive.  In actuality, adhesive is not typically a great choice for weatherproofing purposes as it tends to become brittle and break down in the cold and the adhesive can also become less adherent in warmer temperatures.  Of course, not all adhesives are made equal and some will work better than others, but self-amalgamating tape avoids the issues of adhesive altogether.

It should be noted however, that because self-amalgamating tape adheres to itself it is best used in situations where it is being wrapped around something like a cable or coaxial connector.  Weatherproof tapes are meant for situations where the tape cannot adhere to itself and for all these reasons, self-amalgamating tape, although used for weatherproofing, is not typically the same as tapes that are often referred to as “weatherproof tapes.”

Self-Amalgamating Tape Applications

Self-amalgamating tape is commonly used to help seal, repair, or protect hoses, pipes, and cables.  It is heavily used on electrical joints, often in outdoor applications to protect against weather.  For example, we often have customers who heavily utilize it as weatherproofing for coaxial connectors in the telecommunications, WISP, and satellite industries.  Self-amalgamating tape also sees regular use in the aviation and aerospace industries for similar purposes.   

As previously mentioned, self-amalgamating tape is often used in the marine/sailing market as “rigging tape,” where it protects sails, (and more), from sharp protrusions and chafe.  Similarly, self-amalgamating tape has been used to provide more grip to bike handles, tennis rackets, walking sticks, tools and more.

Self-amalgamating tape is also used by plumbers to help repair leaks, or in the automotive industry to repair radiator hoses and the like.  Self-amalgamating tape truly has an almost unlimited number of applications.


Self-amalgamating tape is truly an incredible product that is almost deceptively simple.  It is so easy to use that it can be easy to disregard the chemical bonding process that allows it be so effective.  With its lack of adhesive, incredible flexibility, not to mention it’s amazing longevity, self-amalgamating tape has an almost infinite number of uses.  

How do you plan on using self-amalgamating tape?  Let us know in the comments below!


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