Loctite Retaining Compound
Secure Cylindrical Assemblies with Confidence
LOCTITE Retaining Compound provides high-strength bonding for cylindrical parts such as bearings, bushings, gears, and shafts. They eliminate loosening, fretting, and corrosion by filling gaps and creating a 100% contact bond between metal surfaces. Designed for industrial reliability, LOCTITE retaining adhesives ensure precision alignment, vibration resistance, and long-term performance — even under extreme conditions.
What Is a Retaining Compound?
A retaining compound is an anaerobic adhesive used to secure and seal cylindrical assemblies. It cures in the absence of air and in contact with metal surfaces, forming a solid thermoset plastic that locks parts together and distributes stress evenly.
How It Works
When applied to a shaft–hub assembly, the liquid adhesive fills microscopic surface irregularities. As the air is excluded, it polymerizes, locking both parts together and preventing movement, wear, or corrosion.
Common Applications
- Fixing bearings and bushings in housings or on shafts
- Bonding gears, pulleys, and rotors
- Rebuilding worn housings or loose fits
- Securing press-fit or slip-fit components
Why Choose LOCTITE Retaining Compounds?
LOCTITE offers a complete range of retaining adhesives for different gap sizes, load requirements, and operating temperatures.
Compared with traditional press fits, pins, or interference fits, LOCTITE compounds provide several key advantages:
Conventional Methods vs LOCTITE Retaining Compounds
A quick, buyer-friendly comparison for cylindrical assemblies (bearings, bushings, sleeves, gears, pulleys).
| Method | Pros | Limits |
|---|---|---|
| Press / Shrink Fit | Strong mechanical hold; familiar in production; no cure time. | Requires tight tolerances/machining; can loosen with thermal cycling; rework may be difficult. |
| Set Screw / Pin / Key | Simple and serviceable; easy field repair; low tooling. | Point loading; can damage shafts; may loosen under vibration; fretting risk remains. |
| Welding / Staking | Permanent retention; good when disassembly is not required. | Heat distortion/HAZ; hard to service; may affect base material and alignment. |
| LOCTITE Retaining Compound | 360° bond line distributes load; reduces fretting; helps seal against moisture/corrosion. | Needs proper cleaning + cure plan; choose grade by gap/temp/serviceability; removal may require heat/tools. |
How to Use LOCTITE Retaining Compounds
Follow these simple steps for reliable, high-strength bonding.
Clean the surfaces
Remove oil, grease, and dirt using LOCTITE SF 7063 or an equivalent cleaner.
Apply activator (optional)
On passive metals (e.g., stainless steel, zinc) or at low temperatures, use LOCTITE SF 7649 to accelerate curing.
Apply the adhesive
- Slip fit: Apply to both parts and rotate during assembly to ensure even coverage.
- Press fit: Apply to the shaft and hub before pressing.
- Shrink fit: Apply to cooled shaft or heated hub and assemble quickly.
Assemble the parts
Align and press components together before the adhesive begins to set.
Allow curing
- Fixture time: a few minutes.
- Full cure: typically 24 hours at room temperature.
Disassembly
- Heat the assembly to ≈ 250 °C and remove while hot.
- Clean the surfaces thoroughly before reapplying.
Product Selection Guide
Use this as a buyer-friendly selector. Always confirm exact limits and cure profiles in the TDS.
| Product | Strength | Max gap | Temp | Oil tolerance | Viscosity | Fixture / Full cure | Disassembly |
|---|---|---|---|---|---|---|---|
| Loctite 638 | High | Check TDS | Check TDS | Standard | Medium | Check TDS | Typically heat + tools |
| Loctite 648 | High | Check TDS | Check TDS | Standard | Medium | Check TDS | Typically heat + tools |
| Loctite 603 | High | Check TDS | Check TDS | Higher | Medium | Check TDS | Heat + tools (often) |
| Loctite 641 | Medium | Check TDS | Check TDS | Standard | Medium | Check TDS | More removable |
| Loctite 640 | Medium–High | Check TDS | Check TDS | Standard | Medium | Check TDS | Removable with tools |
| Loctite 660 | Repair grade | Check TDS | Check TDS | Standard | High | Check TDS | Often heat + tools |
| Loctite 680 | High | Check TDS | Check TDS | Standard | High | Check TDS | Heat + tools |
| Loctite 620 | High | Check TDS | High-temp grade (check TDS) | Standard | Medium–High | Check TDS | Heat + tools (plan removal) |
| Loctite 609 | Medium–High | Check TDS | Check TDS | Standard | Medium | Check TDS | Tools / heat (as needed) |
| Loctite 675 | Varies | Check TDS | Check TDS | Varies | Varies | Check TDS | Varies |
| Loctite 635 | Varies | Check TDS | Check TDS | Varies | Varies | Check TDS | Varies |
Tip: If you can’t find your SKU, use our TDS/SDS library or send your BOM.
Engineering Use-Case Selector
Pick your scenario and send your SKU list—we’ll match the right LOCTITE grade and reply with options.
Bearing Retention (Anti-Fretting)
When to use
Bearings, bushings, sleeves, gears, and pulleys exposed to vibration, shock, or thermal cycling.
Why it works
- Fills micro-clearances to reduce slip and fretting
- Improves circumferential contact and load distribution
- Helps seal the interface against moisture/corrosion
Repair Worn Housings (Gap-Filling)
When to use
Worn housings, slightly undersized shafts, oval bores—when the fit is no longer “tight.”
Why it works
- Designed for repair-style retention on worn cylindrical assemblies
- Better tolerance for larger clearances vs standard retainers
- Helps restore retention without immediate machining
High-Temperature Assemblies
When to use
Assemblies operating at elevated temperatures where standard grades may soften or creep over time.
Why it works
- Higher temperature retaining option for demanding duty
- More stable retention under heat (within TDS limits)
- Removal planning: often requires heat + puller/press tools
Efficient gap filling
Avoid corrosion and friction
High load transfer capacity
Reduce design conflicts
Reduce structural weight
Reduce inventory costs
Top Picks
Tap a SKU to view details. Download TDS, or send an inquiry (SKU will be prefilled).
FAQs
A LOCTITE retaining compound secures cylindrical parts like bearings, bushings, sleeves, gears, and pulleys to prevent movement, vibration loosening, and fretting.
Threadlockers are for threaded fasteners. Retaining compounds (like LOCTITE grades) are for cylindrical assemblies (shaft-to-housing fits).
Not always. A LOCTITE retaining compound can reinforce press fits and also help on slip fits—within the product’s gap capability.
Both are strong general choices. If you prioritize robust general retention, start with LOCTITE 638; if your process values faster handling consistency, consider LOCTITE 648—then verify in the TDS.
LOCTITE 660 is a common starting point for worn parts and repair retention. For larger clearances, consider LOCTITE 680 (verify gap limits in the TDS).
For serviceable bearing mounts, LOCTITE 641 / LOCTITE 640 are typical removable options.
Lower temperatures slow cure. High operating temperatures require the right LOCTITE retaining compound grade (e.g., LOCTITE 620 for higher-temp needs). Always confirm temperature ratings in the TDS.
Cure time for a LOCTITE retaining compound depends on metal type, temperature, cleanliness, and gap. You’ll typically see a handling/fixture stage and a full cure stage—check the TDS for exact guidance.
Some LOCTITE grades are more tolerant than others. If you expect oil contamination, consider LOCTITE 603, but cleaning is still the best practice.
In cold environments, on passive metals (like stainless), or when cure speed matters, a LOCTITE primer/activator can improve cure consistency.
Removal of a permanent LOCTITE retaining compound typically requires controlled heat plus mechanical tools (pullers/press). Choose removable grades when frequent servicing is expected.
Related Guides
Selection tips, comparisons, troubleshooting, and removal—built for engineers and MRO teams.
What Is a Retaining Compound? (Plain-English Guide)
Understand what retaining compounds do, where they’re used, and how they differ from mechanical methods.
Retaining Compound vs Threadlocker: What’s the Difference?
Threaded fasteners vs cylindrical assemblies—choose the right chemistry for the joint type.
LOCTITE 638 vs 648: Which One Should You Choose?
Two popular high-strength options—how to decide based on handling needs and your process.
LOCTITE 660 vs 680: Repair Worn Housings & Gaps
When fits are no longer “tight”—pick the right grade for repair-style retention and clearance.
Retaining Compound Not Curing? 10 Causes + Fixes
Metal type, temperature, oil, gap, and primers—diagnose why cure is slow or inconsistent.
How to Remove a Permanent Retaining Compound (Heat + Tools)
Service planning for “permanent” fits—safe removal workflow and when to choose removable grades.