🧩 VMQ – Standard Silicone
(Heat-resistant elastomeric material, part of the vulcanized silicone family, recognized for thermal stability and constant elasticity. VMQ is a general-purpose thermoset rubber.)
🔹 What is VMQ
VMQ (Vinyl-Methyl-Silicone Rubber) is a cross-linked (vulcanized) silicone rubber based on polysiloxanes. At ReplastMD, we treat VMQ as a high-reliability material for sealing. Its unique structure allows it to remain elastic and stable from –60 °C up to +200 °C. It is non-toxic, odorless, and dimensionally stable. Because it is a thermoset, it does not melt or flow when heated.
🔧 Composition & Properties
- Polymer Base: Polysiloxane (vinyl + methyl).
- Density: 1.10 – 1.20 g/cm³.
- Hardness (Shore A): 30 – 80.
- Operating Range: –60 °C to +200 °C.
- Chemical Resistance: Excellent for water, steam, and most automotive fluids.
- UV Resistance: Exceptional.
🚗 Where VMQ is used in the automotive industry
| Component | Example parts | Observations |
| Gaskets & Seals | O-rings, bellows, seals | Stable elasticity, perfect airtightness |
| Cooling / EGR | Rings, caps, hoses | Temperature and steam resistant |
| Electrical / Sensors | Insulators, boots, protective caps | High dielectric stability, UV stable |
| Anti-vibration | Mounts, buffers | High resilience and elastic damping |
🔧 Welding Temperature and Methods
| Method | Compatibility | Observations |
| Hot Air | ❌ Cannot be welded | Thermoset – does not melt |
| Heat Plate (Mirror) | ❌ Impossible | Degrades under high heat |
| Extrusion | ❌ N/A | Cannot be reshaped after vulcanization |
| RTV Bonding | ✅ Recommended | Neutral/acetoxy silicone adhesives |
💡 ReplastMD Recommendation: VMQ cannot be thermally welded. For repairs or sealing, use specialized RTV (Room Temperature Vulcanizing) silicone adhesives. Total replacement is advised for critical high-pressure components.