Permabond HH040 Anaerobic Retaining Compound

Product Name: Permabond HH040 Anaerobic Retaining Compound (Gap Filling)

Permabond HH040 is a single-component, anaerobic retaining compound designed to lock and seal cylindrical metal assemblies. Unlike standard retaining compounds that require tight tolerances, HH040 is high viscosity and thixotropic, allowing it to bridge larger gaps (up to 0.010") and repair worn parts. It cures when confined in the absence of air between close-fitting metal surfaces, forming a tough, durable plastic that augments or replaces press fits, keys, and splines.

Popular Applications & Uses
- Retaining gears, pulleys, and sprockets onto shafts.
- Repairing worn shafts, housings, and keyways (restoring fit without machining).
- Locking bearings in place where the housing has worn oversize.
- Augmenting slip fits to create high-strength assemblies without the stress of press fits.
- Sealing cylindrical assemblies against leakage and corrosion.

Industries that Commonly Use It
- Heavy Machinery and Equipment Maintenance
- Automotive Repair (restoring spun bearings)
- Mining and Quarrying
- General Industrial Manufacturing
- Pulp and Paper

Special and Unique Features
- Gap Filling: Can fill clearances up to 0.010" (0.25mm), whereas standard retaining compounds usually stop at 0.005".
- High Viscosity / Thixotropic: Paste-like consistency prevents running and dripping during application.
- High Strength: Provides excellent shear strength to transmit loads.
- Corrosion Prevention: Seals the joint completely, preventing fretting corrosion and rust.
- 100% Surface Contact: Distributes stress evenly over the entire joint, unlike keys or splines which concentrate stress.

Key Properties
- Base: Acrylic (Anaerobic)
- Color: Green
- Viscosity: High / Thixotropic (~5,000 cP)
- Shear Strength: ~2,600 - 3,000 psi (Steel)
- Max Gap Fill: 0.010" (0.25 mm)
- Temperature Range: -65°F to 300°F (-55°C to 150°C)
- Fixture Time: 15 minutes

Materials Bonded
- Metals (Steel, Aluminum, Brass, etc.)
- *Note: Does not cure on plastics; designed specifically for metal cylindrical fits.*

Cure Information
- Handling Strength: 15 - 30 minutes.
- Full Cure: 24 hours.
- Cure Mechanism: Anaerobic (requires metal contact + lack of air).

Known backups / known substitutes for this product
- Loctite 660 (Quick Metal): The direct industry standard for gap-filling/repair retaining compound.
- Loctite 638: High strength, high viscosity retaining compound.
- 3M Scotch-Weld RT38.
- Vibra-Tite 541.

Comparison Note
- Permabond HH040 is a "Repair Grade" retaining compound. While standard grades (like Loctite 609 or Permabond HL138) are for new parts with tight tolerances, HH040 is what you use when a bearing has spun and "wallowed out" the hole. It fills the gap and locks the part in place, saving the cost of scrapping the shaft or housing.