In manufacturing and MRO (Maintenance, Repair, and Operations), securing cylindrical assemblies like bearings on shafts, rotors in housings, and bushings requires more than just friction. Traditional mechanical methods—such as press fits, keyways, and splines—often leave microscopic gaps that, under dynamic load and vibration, lead to fretting corrosion, loss of retention force, and catastrophic failure.
The professional solution that engineers rely on to achieve 100% surface-to-surface contact and maximum strength is Anaerobic Retaining Compounds.
This guide explores the engineering function of these essential adhesives and details how the Incure WeldLock™ Seriesof retaining compounds can be precisely selected to optimize assembly reliability, extend equipment life, and reduce costly downtime in high-stakes industrial applications.
What Are Industrial Retaining Compounds?
Retaining compounds are single-component, solvent-free adhesives that cure only when they are deprived of oxygen (anaerobic condition) and in the presence of metal ions (catalysis by the metal surface).
When applied to a slip-fit or press-fit assembly, the adhesive flows into the microscopic gaps between the metal surfaces. Once sealed inside the joint, it rapidly cures into a tough, thermoset plastic, effectively making the assembly a single, solid unit.
Key Benefits Over Mechanical Methods:
- Eliminate Fretting Corrosion: By filling all gaps, the compound prevents micro-movement that causes friction and oxidative wear (fretting), significantly extending component life.
- Increase Load-Bearing Capacity: A retaining compound achieves full surface-to-surface engagement, distributing stress evenly and multiplying the holding power compared to mechanical interference alone.
- Restore Worn Components: High-viscosity retaining compounds are specifically formulated to compensate for large tolerances or worn assemblies, salvaging expensive parts that would otherwise require replacement (e.g., repairing worn keyways or housings).
- Simplify Design: They allow engineers to use looser, easier-to-machine slip-fit tolerances while still achieving structural strength superior to a tight press fit.
Selecting the Right Retaining Compound: Incure’s WeldLock™ Series
The ideal retaining compound is not a one-size-fits-all product. Selection hinges on three critical performance criteria: Strength, Gap Fill (Viscosity), and Temperature Resistance.
The Incure WeldLock™ series offers specialized anaerobic formulations to match these precise industrial requirements:
| Selection Criteria | Incure WeldLock™ Solution | Recommended Product Example |
| Required Strength | High Strength (Permanent): For assemblies that must withstand high dynamic loads (vibration, shock) and thermal cycling without failure. | WeldLock™ 330 (High Strength, Fast Cure for Slip Fits) |
| Medium Strength (Serviceable): For components requiring disassembly for routine maintenance (e.g., small bearings or couplings). | WeldLock™ 338 (Medium Strength, Easy Disassembly) | |
| Gap Fill / Viscosity | Low Viscosity (Slip Fits, Tight Tolerances): Penetrates extremely small gaps (down to 0.05 mm). Ideal for securing pre-assembled parts. | WeldLock™ 309 (Low Viscosity, High Strength Penetrant) |
| High Viscosity (Worn Parts, Large Gaps): Fills larger dimensional tolerances (up to 0.5 mm) and is used specifically for component repair. | WeldLock™ 356 (Metallic Grey, High Viscosity Repair Compound) | |
| Operational Environment | High Temperature Resistance: For parts exposed to motor heat, gearboxes, or harsh industrial environments. | WeldLock™ 347 (High Strength, Fast Curing, rated up to 175°C) |
The Incure Professional Selection Advantage
Incure goes beyond simply supplying a bottle of adhesive. We utilize a targeted consultation process to ensure complete application success:
- Material Analysis: We confirm the metallurgical composition of your shafts and housings, as some passive metals (like stainless steel or zinc plating) may require an anaerobic primer to ensure rapid and full cure activation.
- Fit and Tolerance Measurement: By analyzing the gap size between your components (slip-fit, press-fit, or worn), we recommend the exact viscosity required to achieve maximum fill and eliminate micro-gaps. For example, the high viscosity of WeldLock™ 356 is the ideal solution for salvaging worn-out press-fit parts.
- Speed vs. Strength Balancing: We help you balance required fixture time (how fast you need to handle the part) against final bond strength. Products like WeldLock™ 347 offer rapid fixturing for high-speed assembly while maintaining high thermal resistance.
Maximize Uptime and Reliability
Using the appropriate retaining compound is a critical step in modern mechanical design, converting unreliable friction fits into permanent, high-strength structural bonds that resist dynamic forces.
Ready to enhance the reliability of your rotating equipment, reduce fretting corrosion, and simplify your assembly processes?
Contact an Incure application specialist today for a material consultation and a custom recommendation from the WeldLock™ Retaining Compound series to secure your most demanding cylindrical assemblies.