Shin-Etsu KE-4898 One-Part RTV Silicone Sealant — Electronic Enclosure & Form-In-Place Gasket Application

In power supply housings, LED driver enclosures, sensor modules and small appliance control boxes, traditional pre-cut rubber gaskets are prone to compression set, misalignment during assembly, and cannot accommodate irregular flange shapes. Acid-cure RTV silicones release acetic acid which may corrode copper traces, solder joints and metal housings. A neutral-cure, non-corrosive, plastic-compatible RTV with good unprimed adhesion was required.

The design-in team selected Shin-Etsu KE-4898, a one-part, thixotropic, room-temperature-vulcanizing (RTV) silicone adhesive/sealant that cures by moisture absorption to a tough elastomer.

• Neutral alcohol-cure, non-corrosive: No acetic acid released — safe for Cu/Ag contacts, PCB & metal housings.
• Unprimed adhesion to multiple substrates: Bonds to aluminum, stainless steel, glass, ceramics and many plastics (e.g. ABS, PC, coated surfaces).
• Thixotropic paste: Holds bead shape on vertical/complex flanges — ideal for Form-In-Place Gasket (FIPG) dispensing.
• Low D₄–D₆ siloxane: Stripped of low-MW cyclics — suitable for sensitive contact/optical cavities.
• Electrical insulation & wide temp range: 25 kV/mm dielectric strength; remains elastic from -40°C to +180°C.

• Form-In-Place (FIP) Gasketing​ — Dispense onto aluminum or plastic flange of IP54/IP65-rated power supply or I/O junction box to replace die-cut gaskets.
• Electronic Potting & Sealing​ — Perimeter seal of LED module housings, sensor casings, and communication terminal blocks to block dust/moisture.
• Small Appliance / Industrial Control Box​ — Seal between upper/lower ABS+metal enclosure halves; bonds and seals in one step.

• FIPG bead retained shape after dispensing → uniform compression achieved after enclosure assembly.
• Passed dust & splash water ingress tests (equiv. IP65)​ on assembled enclosures after full cure.
• No discoloration or corrosion on adjacent solder joints / tin-plated terminals after 500 h damp-heat (85°C/85%RH) exposure.
• Maintained elastomeric recovery after thermal cycling (-30°C ↔ +120°C *100 cycles); no loss of adhesion observed on Al and ABS substrates.