Mastic Sealing Tape for Cable Joints - Black Red and Yellow

About Mastic Sealing Tape for Cable Joints - Black Red and Yellow

Gala Mastic Tape is a cold-applied butyl sealant made for use with heat shrink cable joint and termination kits. Applied under or between heat shrink parts, it fills gaps and seals against water and weather, so the finished joint or termination stays dry. It is supplied as pre-cut strips or as rolls on a silicone-coated paper liner.

Three grades do three jobs. Black mastic (HBMT) seals LV and MV joints and terminations, and is also used for sealing telecom installations. Red mastic (HRMT) gives a watertight seal on breakout boots, non-tracking tube and lugs in MV terminations. Yellow stress control mastic (HSCM) fills voids at connectors and screen cuts in MV joints and terminations to relieve electrical stress.

Black strips are 35 mm wide and 2.5 mm thick in lengths from 100 to 450 mm, with rolls from 0.6 m to 25 m. Red strips and rolls come in 20 to 50 mm widths, mostly 1.7 mm thick. Yellow comes in two strip sizes. Black and red typical values include a service temperature of -20 to +90 degC and minimum dielectric strength of 6 kV/mm (black) and 10 kV/mm (red).

Black and red mastic were screened by XRF at an external laboratory in April 2025, and cadmium, lead, mercury, chromium and bromine were not detected.

Buyers include cable jointers, contractors and accessory assemblers who need mastic for kits, repairs and spares.

Manufactured by Gala in India. Datasheet and size selection on request.

Specifications

• Brand: Gala
• Product type: Mastic sealing tape (cold-applied), strips and rolls
• Material: Butyl rubber based mastic sealant on silicone-coated paper liner
• Colour: Black (HBMT), red (HRMT), yellow (HSCM)
• Operating temperature: -20 to +90 degC (service temperature, Gala typical value, black and red)
• Size range: Width 20 to 50 mm; length 100 mm strips to 25 m rolls; thickness 0.7 to 2.5 mm
• Adhesive / sealant: Self-adhesive mastic; good adhesion and self-amalgamation (Gala typical value)
• Application: Water sealing and void filling in heat shrink cable joints and terminations, lugs, breakouts and connectors; telecom sealing (black)
• Installation: Cold applied; peel off the liner and press or wrap into place
• Country of origin: India
• Tensile strength (typical, ASTM D638): Black 0.1 MPa min; red 0.5 MPa min
• Elongation (typical, ASTM D638): 300 % min (black and red)
• Dielectric strength (typical, ASTM D149): Black 6 kV/mm min; red 10 kV/mm min
• Volume resistivity (typical, ASTM D257): Black 1 x 10¹⁰ ohm.cm min; red 1 x 10¹⁴ ohm.cm min
• RoHS: Black and red screened by XRF (external laboratory, April 2025): Cd, Pb, Hg, Cr and Br not detected

Sizes

• Full chart (35 codes) in the datasheet. Summary, W x L x T in mm:
• Black HBMT strips | 35 x 100, 150, 200, 250, 300, 350, 400, 450 x 2.5 | HBMT-01, 08, 02, 15, 10, 03, 04, 05
• Black HBMT rolls | 35 x 600, 1000, 2000 x 2.5 | HBMT-11, 06, 07
• Black HBMT rolls | 40 x 2000 x 2.5; 50 x 500 x 2.5 | HBMT-13, 19
• Black HBMT long rolls | 35 x 25 m x 2.5 | HBMT-14
• Black HBMT thin rolls | 50 x 20 m x 1.3; 30 x 20 m x 1.3 | HBMT-17, 18
• Red HRMT strips | 35 x 100, 150, 200, 300, 400, 450 x 1.7 | HRMT-01, 03, 02, 08, 04, 05
• Red HRMT strips | 25 x 300, 450 x 1.7; 25 x 300, 450 x 1.2 | HRMT-10, 11, 14, 16
• Red HRMT strips | 50 x 400 x 1.7; 20 x 150 x 2.0 | HRMT-20, 24
• Red HRMT rolls | 35 x 600, 1000 x 1.7; 20 x 600 x 1.7 | HRMT-25, 18, 22
• Red HRMT rolls | 25 x 500 x 0.7; 35 x 25 m x 2.5 | HRMT-21, 19
• Yellow HSCM strips | 20 x 100 x 1.7; 25 x 450 x 1.7 | HSCM-06, 09
• Width and length are minimums; thickness +/-5 %. Source: GALA Mastic Tape catalogue sheet, January 2024.

Applications: Heat shrink cable joint and termination kits, cable lug and breakout sealing, cable repair, telecom sealing, cable accessory assembly, utilities and electrical contractors