Overview
Loctite Grade AVV is a very high-viscosity, high-strength anaerobic threadlocker designed to lock and seal large, coarse-threaded metal fasteners. It cures in the absence of air between close-fitting metal surfaces to form a tough, cross-linked plastic that completely fills the thread gap.
Once cured, Loctite Grade AVV:
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Prevents loosening due to vibration, shock and load reversals
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Seals the thread helix against fluid and gas leakage
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Provides long-term protection against rust, fretting and galling
It is particularly suited to large bolts, studs and nuts found on heavy machinery, structural frames and process equipment where maximum resistance to loosening is required.
Why choose Loctite Grade AVV?
1) Very high viscosity for large and coarse threads
Grade AVV’s thick, paste-like rheology lets it stay put in wide thread clearances and on oversized fasteners. It won’t run off or drip, even on vertical or overhead joints, making it ideal for large structural and equipment bolts.
2) High-strength, permanent locking
Formulated as a high-strength grade, Loctite Grade AVV delivers very high breakaway torque on steel fasteners. It’s the right choice when joints are not meant to loosen in normal service and removal, if ever required, is a planned operation.
3) Locks and seals in one step
By filling the entire engagement between male and female threads, Grade AVV both locks the fastener and seals the thread path, reducing the need for additional lock washers, split pins or separate thread sealants.
4) One-part, room-temperature curing
Loctite Grade AVV is a single-component liquid/paste that cures at room temperature. No mixing, no separate hardener—just apply, assemble and allow it to cure.
5) Designed for demanding environments
The cured adhesive forms a tough, thermoset polymer that withstands vibration, shock and thermal cycling in harsh industrial conditions, helping maintain clamp load and joint integrity over time.
Typical Applications
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Large bolts and studs on pumps, compressors and gearboxes
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Structural fasteners on frames, presses, cranes and heavy machinery
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Big flange joints and housings in mining, construction and materials handling equipment
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Large threaded connections in power generation, marine and processing plants
Loctite Grade AVV is intended for metal-to-metal threaded joints and is not recommended for plastic threads or for pure oxygen / strong oxidizer systems.
How to Use Loctite Grade AVV
Step 1 – Surface preparation
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Remove loose rust, dirt, coatings and old threadlocker from the threads.
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Wipe away heavy grease, thick oil and anti-seize.
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Light industrial oil films may remain, but for the most critical joints, solvent-clean to bare metal.
Step 2 – Apply the threadlocker
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Dispense a suitable amount of Loctite Grade AVV from the bottle or tube.
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Apply a continuous band around the male threads, covering the full engagement length.
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Because Grade AVV is very viscous, you can easily control the bead and keep it where it’s needed.
Step 3 – Assemble and tighten
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Assemble the joint promptly after application.
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Tighten the fastener to the specified torque value.
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Avoid repeatedly loosening and re-tightening once the adhesive has started to fixture.
Step 4 – Cure and return to service
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Allow the joint to remain undisturbed until handling strength is reached.
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For maximum performance under heavy load and vibration, allow up to 24 hours at room temperature before subjecting the assembly to full operating conditions.
Step 5 – Disassembly (if ever required)
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Loctite Grade AVV is a high-strength permanent threadlocker.
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Small fasteners may be removed with strong hand tools, but larger bolts typically require:
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Localized heating of the fastener area (only if compatible with base materials and design) to soften the cured adhesive, and
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High torque with appropriate tools to break the bond while the joint is still hot.
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Safety & Handling
As with most anaerobic threadlockers, typical safety considerations for Loctite Grade AVV include:
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May cause eye and skin irritation on contact
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Repeated or prolonged exposure can cause skin sensitisation in some individuals
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Vapours or mists may cause mild respiratory irritation in poorly ventilated areas
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Uncured product may be harmful to aquatic life if released uncontrolled
Good practice
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Use in a well-ventilated area.
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Avoid contact with skin and eyes; wear safety glasses and suitable protective gloves.
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Wash hands thoroughly after handling and before eating or drinking.
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Do not dispose of uncured product into drains or natural waterways.
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Store in the original, tightly closed container in a cool, dry place, away from heat and direct sunlight.
Always follow the latest Safety Data Sheet (SDS) for Loctite Grade AVV in your region.
FAQs
Q1: What is Loctite Grade AVV used for?
Loctite Grade AVV is used as a high-strength threadlocker for large, coarse-threaded metal fasteners where you need permanent locking and reliable sealing in heavy-duty industrial service.
Q2: How is Grade AVV different from standard liquid threadlockers?
Most standard grades are lower viscosity and aimed at small-to-medium fasteners. Grade AVV is a very high-viscosity, gap-filling product designed specifically for big bolts, coarse threads and wider clearances, where thinner liquids may not stay in place or fully fill the joint.
Q3: Is Loctite Grade AVV removable?
Loctite Grade AVV is considered a permanent high-strength threadlocker. Small fasteners may come loose with strong tools, but larger bolts usually require localized heating and high torque for safe disassembly.
Q4: Can I use Grade AVV on stainless steel or plated fasteners?
Loctite Grade AVV can be used on many common metals, including carbon steel and many plated fasteners. Cure speed and strength can vary with substrate; on more passive metals, allow additional time before applying full load.
Q5: Is Loctite Grade AVV oil-tolerant?
For best results—especially on large, critical joints—threads should be reasonably clean. Light oil residues may be tolerated, but heavy oil, grease and anti-seize should be removed to achieve consistent high-strength performance.
Q6: Can I use Grade AVV on plastic threads or mixed metal/plastic joints?
No. Anaerobic threadlockers like Loctite Grade AVV are formulated for metal-to-metal threads and can cause stress cracking in some plastics. They also do not cure properly on non-metal surfaces.
Q7: Does Loctite Grade AVV also seal against leaks?
Yes. By filling the gap between male and female threads, Loctite Grade AVV locks and seals at the same time, helping to prevent low-pressure leakage along the thread helix and providing a barrier against corrosion.
