In form-wound low-voltage and medium-voltage motor manufacture, Saint-Gobain CHR 2915-7 is applied over winding lead junctions, phase-to-phase crossovers, and connection lug insulations before vacuum pressure impregnation (VPI). The glass cloth backing withstands mechanical working from lacing cords and braze fillet contours without tearing. The silicone adhesive retains peel strength when the winding is preheated to 55°C to 70°C for resin viscosity reduction. A 25 mm wide strip applied at 50% overlap advances 12.5 mm per turn and places two backing layers over the metal surface. Where resin penetration is required, the first wrap is spaced with a 1.5 mm to 3.0 mm butt gap between adjacent turns; the second wrap is half-lapped with no gap. The silicone adhesive is formulated without corrosive sulfur species, avoiding copper sulfide attack on magnet wire enamel. Compliance evidence for UL-listed insulation systems relies on UL 510 recognition of the tape as a flame-retardant polymeric component and tape property data generated under ASTM D1000.

During VPI, tank pressure cycles between 1.5 bar and 6.0 bar depending on resin mass and winding size. Typical Class H epoxy-polyester VPI resins show mixed viscosity between 400 cP and 700 cP at 60°C. The glass cloth weave restricts resin from displacing a properly burnished wrap. A process failure mode occurs when wrap tails are not bedded into the slot exit or lead stub. Entrained air from incomplete roller burnishing expands during vacuum pull-down and lifts the tape from the copper surface. This produces resin-rich voids and partial discharge risk under full voltage. On mid-size traction motor lines, batch VPI vessels with working diameters of 1,500 mm to 2,200 mm and cure ovens rated at 180°C are typical. Tape removal after cure is not required; the material remains in the insulation system. Terminal products include mine-haul traction motors, marine propulsion motors, and steel-mill auxiliary motors rated for thermal class 155°C or 180°C.

Open-wound dry-type transformer production specifies the tape for lead insulation, winding edge protection, and barrier layer wrapping on rectangular aluminium or copper foil coils. The 0.007 in (0.178 mm) nominal backing thickness is confirmed under ASTM D374 by dead-weight micrometer loading. A two-thirds overlap on foil edges places three glass cloth layers at the highest mechanical stress line where subsequent coil handling or bus bar attachment occurs. The tape is applied dry; no solvent wiping is advised because fluid residues alter silicone PSA anchorage and may create voids in the cast resin block. Winding temperatures before tape application are held below 45°C to prevent premature adhesive softening. In cast-coil processes, the completed winding is placed into a mould and filled with a filled epoxy or polyurethane resin system. The silicone adhesive is compatible with the resin exotherm but is not a moisture barrier substitute for the cast insulation. Compliance is evaluated under IEC 60076-11 for dry-type power transformers and under ASTM D1000 for tape peel adhesion and electric strength. Terminal products include 11 kV and 33 kV distribution transformers, offshore platform auxiliary transformers, and reactor coils for variable-frequency drive filters.

What Limits Adhesive Residue After Thermal Spray Masking on Gas Turbine Hardware?

When plasma spray or high-velocity oxy-fuel (HVOF) coating is applied to gas turbine blades, combustion liners, or landing gear journals, the tape is used as edge definition masking over surfaces that must remain uncoated. A 6 mm overhang is positioned along the component edge, and successive strips are butt-joined with 2 mm to 3 mm spacing on the cold side to avoid coating wedge formation. The glass cloth backing deflects peripheral ceramic or carbide particles without igniting, unlike polymer film masks. Process-side surfaces are pre-cleaned with isopropyl alcohol and dried until the surface temperature reaches 20°C to 25°C. The tape is burnished with a roller exerting 15 N to 25 N to eliminate air entrapment. During thermal spray, workpiece surface temperatures can fluctuate between 120°C and 250°C; the silicone PSA maintains residue-free removal when the component is cooled to 60°C or below before peeling. Published peel-test data for this specific tape under thermal spray heat aging is limited; therefore, in-house qualification on a masked test coupon with a defined spray angle of 90° or 60° is required before production masking. Terminal products include superalloy blade roots protected from grit blast and spray, journal surfaces for aircraft landing gear hydraulic seals, and pump shaft bearing lands. Compliance for thermal spray masking is governed by the shop’s surface preparation standard such as ISO 14922 for thermal-sprayed coatings, with coating adhesion tested under ASTM C633.

Composite Cure Masking and Bag Side-Seal Maintenance at 177°C and 0.59 MPa

In carbon-fibre-reinforced polymer autoclave curing, the tape is used to mask composite tooling edges, seal bagging film pleats, and anchor release film to the tool face. The glass cloth backing resists fibre bed compaction pressure without splitting, while the silicone adhesive prevents resin bleed from wicking beneath the tape edge. A single strip of 50 mm width is applied over the bag sealant tape edge with 10 mm seating on the bag film and 40 mm contact on the tool flange. At 177°C and 0.59 MPa autoclave pressure, the tape must not leave silicone residue on composite after the cure cycle. Silicone adhesive migration into laminate surfaces is evaluated using water break-free tests and, where applicable, ATR-FTIR spectral comparison of post-cured tool-side surfaces against an as-received control. Process boundary: repeated cure cycles above 200°C or dwell times beyond 6 h can reduce peel clean-release margin; qualification should include a three-cycle autoclave exposure with 90° peel removal at room temperature. Terminal products include wing spars, fuselage frames, and nacelle inner barrels. Compliance is documented within the OEM’s cure specification, typically derived from ASTM D3039 for laminate mechanical properties and ASTM D3535 for adhesive shear, while tape physical properties remain traceable to ASTM D1000.

When Silicone Release Liner Splicing Demands Zero-Slip Butt-Splice Performance

Silicone-coated release liners are spliced between unwinding rolls in adhesive coating and die-cutting operations to maintain continuous web throughput. The glass cloth tape’s silicone PSA bonds to low-surface-energy liner surfaces where acrylic adhesives lose tack after 24 h. A butt splice is made with liner ends cut straight and separated by 0.5 mm to 1.0 mm; a 25 mm length of CHR 2915-7 is centered over the joint and pressed with a laboratory hand roller at 50 N. Web speeds up to 150 m/min and tension levels of 15 N to 25 N per 100 mm web width are typical for label-stock release liner runs. The tape thickness of 0.178 mm produces a measured splice caliper increase, which must be checked against die-strike tolerance in downstream flatbed cutting. If the splice passes through a rotary die station, the splice is cushioned by reducing line tension by 10% for 30 s after the splice enters the die. Terminal products include glassine and polymer film release liners for pressure-sensitive label stock, medical device pouches, and graphic film lamination. Compliance for liner splice acceptance is covered by ISO 9001 work instructions and visual inspection of splice alignment after 1,000 running meters; tape physical properties are measured under ASTM D375 and ASTM D1000.

Aerospace Wire Harness Overwrap for Silicone Rubber-Insulated Cables

On aircraft engine harnesses and auxiliary power unit wiring, the tape is applied over silicone rubber-insulated conductors to provide bundle consolidation and chafe protection at high-temperature zones. The wrap is applied with 50% overlap, resulting in two glass cloth layers over the bundle. At connector backshells, a strain-relief build-up of three to five wraps is used; each wrap is held under 10 N tension to avoid cutting into silicone insulation. Harness testing followed by OEM qualification includes dry arc propagation resistance often evaluated under AS4373 Method or FAR 25.853 appendix for flammability when the tape is included in harness-level burn tests. The silicone adhesive does not degrade the silicone jacketing, and no plasticizer migration from polyvinyl chloride jackets occurs because the tape is specified only for silicone-jacketed bundles in this harness class. Published data for this specific configuration in full-scale fire tests is limited; qualification must be performed at the harness manufacturer’s facility with the actual wire gauges and connector fittings. Terminal products include engine EGT probe harnesses, APU fuel control harnesses, and bleed-air sensor harnesses. The tape lot is traceable to ASTM D1000 test certificates for peel adhesion and tensile strength.