Fasto A177 – Permanent Threadlocking for Large & Critical Fasteners
Fasto A177 is a single-component, very high-strength (permanent) anaerobic threadlocking compound developed to lock metal fasteners and prevent loosening caused by vibration, shock, and thermal cycling. It cures in the absence of air when confined between close-fitting metal threads, forming a durable, vibration-resistant bond.
Formulated with enhanced gap-filling capability, Fasto A177 is suitable for large threaded fasteners up to 36 mm, making it ideal for heavy industrial and automotive assemblies where maximum strength and reliability are required.
Very High / Permanent Strength Breakaway torque up to 36 Nm and prevailing torque up to 31 Nm (M10 steel fasteners).
Excellent Gap Filling Ability Effective on threads with gaps up to 0.25 mm.
Anaerobic Cure Technology Cures only when confined between metal parts.
Fast Strength Build-Up Fixture time of 5–10 minutes.
Wide Operating Temperature Range -50°C to +150°C (continuous).
Thixotropic (Non-Drip) Nature Prevents run-off on vertical or overhead assemblies.
Corrosion Protection Prevents rust and fretting on assembled fasteners.
Green Colour Easy visual identification during application and inspection.
Benefits
Prevents vibration-induced loosening and leakage
Ensures permanent locking of critical fasteners
Ideal for large bolts, studs, and coarse threads
Reduces maintenance and re-tightening
Enhances safety and durability of heavy machinery assemblies
Primary Application
Sub-Applications
Functional Purpose
Key Performance Advantage
Permanent Thread Locking
Medium to coarse threaded screws, nuts & bolts
Prevent loosening and leakage permanently
Very high breakaway & breakloose torque
Large & Heavy Fastener Locking
Large-diameter bolts, studs (up to large sizes)
Secure critical fasteners under load
Enhanced gap-filling for larger threads
Heavy Industrial Assemblies
Conveying systems, foundation bolts
Maintain joint integrity in continuous operation
Excellent vibration & shock resistance
Automotive Chassis & Structural Fasteners
Chassis bolts, load-bearing joints
Long-term fastening reliability
Permanent locking for safety-critical joints
High-Vibration Machinery Fasteners
Dynamic machinery & equipment
Prevent back-out during operation
Thixotropic – no run-off or migration
Leak Prevention in Threaded Joints
Threaded joints exposed to oils & fluids
Seal threads against leakage
Anaerobic cure fills micro-gaps
Corrosion Protection of Threads
Outdoor & harsh-environment fasteners
Protect assembled parts
Seals threads from moisture & contaminants
Surface Preparation
Ensure threads are clean, dry, and free from oil, grease, and contaminants.
Proper cleaning is essential for maximum bond strength and consistent curing.
Application Method
Apply Fasto A177 to all engaged threads.
Assemble the fastener and tighten as required.
Allow the joint to cure under anaerobic (air-excluded) conditions.
Wipe off excess adhesive from the outside of the joint.
Curing Guidelines
Fixture time: 5–10 minutes
Full cure: 12 hours
Maximum recommended gap: 0.25 mm
Additional Notes
Cure speed depends on temperature, bond gap, and substrate type.
On inert metals (stainless steel, aluminium) or at temperatures below 5°C, use Fasto AP49 Activator to accelerate curing (note: activator may reduce final strength by up to 30%).
Not recommended for certain plastics due to possible stress cracking.
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