🧩 FPM – Fluoroelastomer (Viton®)
(Fluorinated elastomeric material with exceptional thermal and chemical resistance. FPM is the ISO abbreviation for fluoroelastomers also known as FKM. In practice, FPM = FKM = Viton®, the commercial name introduced by DuPont.)
🔹 What is FPM
FPM (Fluoroelastomer) is a fluorocarbon-based synthetic rubber. At ReplastMD, we treat FPM as the ultimate technical barrier. It provides unmatched durability in contact with fuels, acids, and synthetic oils, maintaining its integrity up to 250 °C. As a vulcanized thermoset, it does not melt under heat. It is the standard choice for engine seals, transmission gaskets, and EGR systems.
🔧 Composition & Properties
- Polymer Base: Fluorocarbon copolymer (VDF + HFP + TFE).
- Density: 1.80 – 1.20 g/cm³ (very dense and heavy).
- Hardness (Shore A): 60 – 90.
- Operating Range: –25 °C to +250 °C.
- Chemical Resistance: Exceptional (oils, fuels, acids, bases).
🚗 Where FPM is used in the automotive industry
| Component | Example parts | Observations |
| Engine / Transmission | O-rings, valve stem seals | Excellent heat and oil resistance |
| Fuel / EGR Systems | Valves, hoses, fittings | Stable against hydrocarbons |
| Braking / Vacuum | Diaphragms, seals | Compatible with DOT and ATF |
| Sensors | Insulation, connectors | Chemically inert |
🔧 Welding Temperature and Methods
| Method | Compatibility | Observations |
| Hot Air | ❌ Cannot be welded | Thermoset – chars and degrades |
| Heat Plate (Mirror) | ❌ Impossible | Thermally degrades above 200 °C |
| Extrusion | ❌ N/A | Cannot be reshaped after curing |
| Chemical Bonding | ✅ Recommended | Viton® specific adhesives / Loctite 480 |
💡 ReplastMD Recommendation: FPM cannot be thermally welded. It can only be chemically bonded using fluoroelastomeric adhesives and activating primers. For critical seals, complete part replacement is always preferred.