The term “mastic” is widely used in the construction industry, especially by tile setters. Many electricians don’t realize that the gooey electrical tape they use to resist moisture is also a mastic. But this mastic rubber material is specially formulated for use as a dielectric insulator. Mastics from 3M are compatible with thermoplastic rubber wire insulation.
When you are working with odd shaped components or needing to tuck in some insulation where your tape won’t reach; mastic is the product to use. Think of it as putty on a roll.
Humidty? Moisture? Wrap it up!
In addition to low-voltage electrical insulation, mastic tape offers the best moisture resistance of any electrical tape made by 3M. They create a barricade around splices and terminations, so that they are resistant to contaminants and particles that can corrode your wire and connections. Mastic tapes are often used in outdoor applications because the rubber is ‘self-healing’, meaning that when it is punctured, the material will flow to fill in the void.
We recommend it for use within industrial environments where steam and aerosols are commonly present, and outdoor environments where connections need to resist humidity and moisture. For electrical connections that are continually submerged in liquids, 3M has other solutions like Electrical Resins.
Built for the odd shape and the long stretch.
Mastic tapes provide mega-stretch−up to 1000 times their original length. Sharp edges and bolted connections create potential puncture risks and failure modes for your splices which can result in costly downtime and repairs. With multiple configurations and thicknesses of moldable and stretchable sheets, rolls, putty and laminated combinations, you can shape, smooth and pad just about any electrical connection. 3M mastic products provide plenty of options for insulating and weatherproofing odd shapes and complex configurations like:
Exceptionally pliable; it can be rolled into tubes or spheres or crafted into any shape to fill crevices left by tape splicing, especially on bifurcated cables. A mastic that’s used for this purpose is 3M™ Scotchfil™ Electrical Insulation Putty. Scotchfil putty is 125 mils thick and comes on a linered roll for easy transport and flexible sizing for your application.
There is another mastic application electricians may be surprised to learn about. Mastic tape can be used to deter pests. Fire ants in the Southeastern U.S. create headaches for electricians by attacking pad mounted transformers, traffic control panels and ground level air conditioning units. *According to research done at Texas A&M University, the insects are attracted to the electrical fields, especially around relay switches. Power surges caused by these pests can cost thousands of dollars in electronics repairs or even human lives if those relays operate train switches.
Pests and rodents can cause havoc. Help reduce your regular maintenance costs with a simple mastic solution.
*Merchant, Mike. “Insects in the City: Fire ants shock homeowners.”
http://insectsinthecity.blogspot.com/2009/06/fire-ants-shock-homeowners.html (accessed September 15, 2017).
Keep a box of Scotch® Vinyl Mastic Pads 2220 in your maintenance truck or toolbox. They are ideal for fast installation around connections and splices and can be used when repairing damage caused by unplanned moisture or pests.
Jackets required. This tape can ooze.
Mastic is going to flow. So, for the better mechanical protection and to help prevent it from making a mess in your application; mastic should be completely overwrapped with another protective material like vinyl (PVC) or rubber tape. To make your job easier, 3M offers laminated solutions that combine these materials for one step applications.
If Scotch® Rubber Mastic 2228 is applied in a gritty, rough environment, electricians may create added mechanical protection by overwrapping with Scotch® Vinyl Electrical Tape Super 88. Vinyl tape helps your splices and terminations resist copper corrosive chemicals and acids.
There is a mastic for virtually every application.
Mastic comes in tape and roll form and in a variety of thicknesses and operating temperatures.
Even with a lot of information, understanding the pros and cons and picking a tape can be tricky. Let 3M save you time with these application summaries and quick product comparisons to find the right mastic solution for your application.
Choose mastic only when you need padding, flexibility and conformability to manipulate the material to fit on or in your application. At 125mils, they are your thickest options - but these tape, pads and putty are versatile and can be cut, stretched, scrunched and rolled to fit in even small spaces. However, you will still have to wrap another material like vinyl over it to contain the mastic and provide jacketing protection.
Choose a vinyl mastic when you need quick installations and outdoor performance. You get the moisture sealing benefits with a slightly thinner mastic, without the added step of overwrapping with a vinyl tape. Great for fast maintenance, insulating and padding low voltage connections and cable jacket repair.
Scotch® Vinyl Mastic Pad 2200 and Roll 2210 combine thicker mastic layers with the world-class performance benefits of Scotch® Super 33+™ Vinyl Electrical tape and allow installation down to 0oF (-18oC).
Scotch® Electrical Moisture Sealant Pad 06149 and Roll 06147 are half as thin and utilize 3M™ Temflex™ Vinyl Electrical Tape 1700 for abrasion and puncture resistance down to 32oF (0oC)
Choose rubber mastic for insulating, padding and resisting moisture in high voltage applications up to 1000V. The layer of Scotch® Linerless Rubber Tape 130C dissipates heat and works up to 90oC with an overload temperature of 130oC
Choose a cable jacket repair tape for preventative cable maintenance, and on-site repairs in rough environments like construction sites, steel mills, petrochemical plants and industrial manufacturing. They include flame-retardant mastic to keep moisture away and provide excellent adhesion to a variety of cable jacket materials.
You have a wide array of choices. This easy to read chart will give you performance ratings in a glance.
There are some basic rules to follow when you’re selecting electrical tape.
Get more information on product selection, applications and training in our Electrical Resource Center.