Fasto A339 - Retaining Adhesives

Fasto A339 – Super High Strength Anaerobic Retaining Compound

Fasto A339H – Heavy-Duty Retaining & Sealing Solution for Cylindrical Assemblies

Fasto A339H is a single-component, super fast curing, super high strength anaerobic retaining compound developed for retaining, sealing, and locking cylindrical metal components. It cures in the absence of air when confined between close-fitting metal surfaces, forming an exceptionally strong and durable bond.

Specially engineered to enhance press-fit and slip-fit assemblies, Fasto A339H provides excellent resistance to heat, vibration, and chemical exposure, making it ideal for power transmission and heavy-duty industrial applications.

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Key Features

  • Super High Retaining Strength
    Shear strength up to 34 N/mm² for critical load-bearing assemblies.
  • Anaerobic Cure Technology
    Cures only between metal parts, ensuring controlled and reliable bonding.
  • Fast Fixture Time
    Achieves handling strength in less than 6 minutes.
  • Excellent Heat Resistance
    Continuous service up to 175°C, intermittent exposure up to 210°C.
  • Gap Filling Capability
    Suitable for gaps up to 0.25 mm.
  • Corrosion Protection
    Prevents fretting and corrosion between mating metal parts.
  • Lubricating Effect During Assembly
    Allows smooth positioning of parts before curing.

Benefits

  • Permanently retains and locks cylindrical components
  • Increases load-carrying capacity of press-fit assemblies
  • Eliminates the need for mechanical fasteners or interference fits
  • Reduces loosening due to vibration and thermal cycling
  • Ensures long-term reliability in harsh industrial environments
Primary Application Sub-Applications Functional Purpose Key Performance Advantage
Cylindrical Part Retention Locking sleeves, bushes, collars Permanent retention of cylindrical components Super high shear strength for critical assemblies
Bearing & Bushing Retaining Bearings on shafts, bushings in housings Prevent rotation, loosening & fretting Augments press-fit and slip-fit strength
Gear, Pulley & Sprocket Retention Gears, pulleys, sprockets on shafts Reliable torque transmission Excellent vibration & shock resistance
Rotor & Shaft Assembly Motor rotors, generator shafts Maintain concentricity and load transfer High strength with controlled gap filling (up to 0.25 mm)
Pump, Gearbox & Turbine Assemblies Pumps, gearboxes, turbines, compressors Structural retention under load & heat Excellent heat resistance and long-term durability
Industrial & Automotive Assemblies Motors, generators, mechanical drives Prevent loosening and corrosion Anaerobic cure protects against corrosion
Thread Locking & Sealing (Secondary Use) Threads requiring very high strength Lock and seal threaded joints Extremely high breakaway strength

Surface Preparation

  • Ensure parts are clean, dry, and free from oil, grease, dust, and contaminants.
  • Proper surface cleanliness is essential for maximum bond strength.

Application Method

  1. Apply Fasto A339H evenly to all engaged surfaces.
  2. Assemble parts immediately.
  3. Allow the joint to cure under anaerobic (air-excluded) conditions.
  4. Wipe off excess adhesive from the outside of the joint.

Curing Guidelines

  • Fixture time: < 6 minutes
  • Full cure: 8 hours
  • Maximum recommended gap: 0.25 mm

Additional Notes

  • Cure speed depends on temperature, bond gap, and substrate type.
  • On inert metals (stainless steel, zinc-plated parts) or at temperatures below 5°C, use Fasto AP49 Anaerobic Activator to accelerate cure (note: activator may reduce final strength by up to 30%).
  • Not recommended for certain plastics due to potential stress cracking.

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