Silicone grease (PDMS-based with fumed silica thickener) covers a service window from -50 to +200 °C, is inert to most chemicals, and uniquely compatible with rubber elastomers (EPDM, silicone, EPDM/NBR with caution). Used in plumbing O-ring lube, electrical dielectric (spark plug boot, connector), brake caliper guide pin, automotive door / window EPDM seal, food-machine valve seal (NSF H1) and pharmaceutical equipment. This guide gives the recommended BOM and Indian sourcing.
| Component | Function | % (m/m) | Indian Supplier |
|---|---|---|---|
| PDMS silicone oil 350-1000 cSt | Primary base — viscosity tuned per application | 82.0% | Dow Corning / Shin-Etsu / Wacker silicones |
| Fumed silica (Aerosil R972 hydrophobic) | Primary thickener | 11.0% | Evonik Aerosil / Cabot Cab-O-Sil |
| Low-MW PDMS 50 cSt | Dispersion carrier for silica | 5.0% | Dow Corning / Shin-Etsu |
| HMDZ-treated fumed silica (stability) | Anti-settling, gel stability | 1.5% | Evonik / Cabot |
| BHT-equivalent silicone-compatible AO | Antioxidant (silicone AO grade) | 0.2% | Specialty AO suppliers |
| Optional — ZDDP AW (only if AW needed) | Anti-wear for brake-pin variant | 0.3% | Lubrizol / LC-AW-ZDDP |
| TOTAL | 100.0% | — | |
Process: shear-disperse fumed silica in low-viscosity PDMS at high speed (5,000-10,000 RPM, high-shear mixer) until silica platelets exfoliate and gel begins to form; gradually add higher-MW PDMS while maintaining high shear; let batch mature 24-48 hr; final 3-pass mill to NLGI 2 consistency. QC: NLGI 2 (270-285), no drop point, dielectric strength 12-15 kV/mm, EPDM compat — volume change <2% after 168 hr at 80 °C. Ex-works cost ₹620-950 / kg at 5 MT batch. NSF H1 grade requires food-grade-registered silicone oil — ₹1,100-1,800 / kg.
Silicone grease is grease made by thickening polydimethylsiloxane (PDMS) silicone oil with fumed silica or PTFE micropowder. Three key properties: (1) Extremely wide temperature range — service -50 to +200 °C continuous. (2) Inert to most chemicals — water, dilute acid/alkali, alcohol. (3) Compatible with rubber elastomers (EPDM, silicone, NBR with caution) — does not swell or attack.
Applications: plumbing O-ring, electrical dielectric (spark plug boot, ignition coil), brake caliper guide pin, automotive door / window EPDM seal, food-machine valve seal (NSF H1), pharmaceutical equipment.
NLGI 2 silicone grease BOM (%): PDMS silicone oil 350-1000 cSt 82%, fumed silica (Aerosil R972) 11%, low-MW PDMS 50 cSt carrier 5%, HMDZ-treated fumed silica 1.5%, AO 0.2%, optional ZDDP 0.3%. Process: shear-disperse fumed silica in low-viscosity PDMS at 5,000-10,000 RPM until silica platelets exfoliate and gel forms; mature 24-48 hr; final mill to NLGI 2.
NLGI 2, no drop point, dielectric strength 12-15 kV/mm, EPDM compat — volume change <2% after 168 hr at 80 °C.
Fumed silica (high-surface-area SiO2 made by flame hydrolysis, Aerosil / Cab-O-Sil brands) is the standard thickener for silicone grease because: (1) Chemically inert. (2) Very high surface area (~200 m²/g) — needs only 8-15% to gel PDMS. (3) Reversible structure — recovers from shear. (4) Available in hydrophobic surface-treated grades.
PTFE micropowder (1-3 µm) is the alternative — used in premium dielectric and o-ring grease where PTFE's low friction is valued. Treat 10-20% PTFE.
Both are silicone grease but with subtle differences. Dielectric grease (Dow 4 Compound, Permatex Dielectric Grease) — emphasises high dielectric strength (12-20 kV/mm), used in spark plug boots, ignition coil, electrical connectors. No conductive contaminants.
O-ring grease (Dow 111 valve lubricant) — emphasises rubber elastomer compatibility, low oil bleed, persistence under sealing pressure. Used in plumbing O-rings, faucet O-rings, scuba diving regulator, RV / boat plumbing. Same basic PDMS + fumed silica chemistry; treat rates and additive choices differ by application.
Brake caliper guide pin lubrication uses silicone grease because the pin contacts EPDM dust boots that would be attacked by mineral grease (mineral oil swells EPDM). Silicone grease is rubber-friendly. Specific formulation has slightly higher viscosity PDMS (1000-5000 cSt) for sustained boundary lubrication and added Mo solid lubricant (1-3% MoS2 or graphite) for shock-load protection.
Brands: Permatex Ceramic Brake Lubricant, Liqui Moly Bremsenpaste, Wurth Brake Caliper Lube. ₹450-850 / 100g tube. India aftermarket increasingly demands this — 4W brake caliper repair standard.
Brands: Dow Corning Molykote 111 (plumbing/valve), Dow Corning 4 Compound (dielectric), Permatex Dielectric Grease, Liqui Moly Silikon-Fett, Wurth Silicone Grease, Bardahl. ₹220-680 / 100 g tube or 500 g jar.
Indian applications: 2W/4W brake caliper aftermarket, 4W ignition wiring, plumbing (Jaquar, Kohler, Cera, Hindware OEM), pharmaceutical equipment seal (Sun Pharma, Cipla, Dr Reddy's), food/dairy valve (NSF H1 — Amul, Mother Dairy, Britannia). Lubechem custom (LC-GR-SIL-NLGI2) ex-works ₹620-950/kg in 5+ MT batch. NSF H1 silicone grease ₹1,100-1,800 / kg.
Share your application (plumbing / dielectric / brake / NSF H1), pack format (tube / jar / drum) and volume. We respond within one business day.