Loctite GRADE AV

Overview

Loctite Grade AV (often referenced as Loctite 087) is a red, low-to-medium viscosity, high-strength anaerobic threadlocker based on acrylic (dimethacrylate ester) chemistry.

It cures in the absence of air and in contact with metal to form a tough, thermoset plastic in the thread gap. Once cured, it resists vibration, shock, leakage and loosening, and is intended for permanent locking of larger threaded fasteners where disassembly is infrequent or requires significant effort.

Why engineers choose Loctite Grade AV

1) High-strength locking for coarse threads
Grade AV is formulated for large, coarse-threaded nuts, bolts and studs, providing high break and prevail torque on assemblies that see heavy loads and continuous vibration.

2) Medium viscosity for good wetting and gap filling
Its medium viscosity helps it wet coarse thread flanks and fill typical clearances without excessive run-off, giving a consistent bond line on vertical or overhead joints.

3) Dual function: locks fasteners and seals porosity
Beyond locking, Loctite Grade AV is widely used to seal porosity in welds, castings and powdered metal parts, helping prevent seepage of oils, fuels, coolants and process fluids.

4) Proven performance to military and industrial specs
The product is listed as meeting MIL-S-22473E and classified under ASTM D5363 Group 1, Class 2, Grade 3, giving confidence for aerospace, defense and other critical applications.

5) One-component, room-temperature cure
Grade AV is supplied as a single-component liquid in a 50 ml red squeeze bottle. It requires no mixing and cures at room temperature when confined between active metal surfaces.

Typical Applications

Heavy-duty threaded joints

• Large nuts, bolts and studs on pumps, compressors and gearboxes

• Powertrain mounts, engine brackets and drivetrain components

• Large flanges and covers where loosening would be critical

Industrial & process equipment

• Valves, fittings and mechanical joints in process lines

• Fasteners on heavy machinery, presses and construction equipment

• Structural frames subject to high vibration or shock loading

Porosity sealing

• Sealing micro-porosity in welds and fabrication repairs

• Sealing pores in castings and powdered metal parts to prevent fluid weepage

Loctite Grade AV is best suited to metal-to-metal assemblies where permanent retention and long-term seal integrity are required.

Key Technical Data

• Technology / Chemistry: Anaerobic acrylic, dimethacrylate ester

• Color (uncured): Red liquid

• Viscosity (approx.): Medium, typically ~100–250 mPa·s (cP)

• Strength rating: High; intended as permanent threadlocker

• Fixture time / begins to harden: On the order of minutes (e.g. ~10 min on steel test assemblies)

• Full cure / full strength: Typically within 24 hours at room temperature (range 6–72 h depending on substrate and gap)

• Thread size range: Up to approx. 1″ coarse threads (typical spec sheets reference 1″ test threads)

• Break torque (3/8-16 steel): Approx. 250 in·lb; prevailing torque ~275 in·lb (typical data)

• Typical package size: 50 ml bottle (other sizes may be available regionally)

Values above are typical and not intended for specification purposes. Always consult the current Henkel TDS for design calculations.

How to Use Loctite Grade AV

Step 1 – Prepare the surfaces

• Clean threads to remove heavy oil, grease, dirt and old threadlocker.

• Light factory oil films are usually acceptable, but heavily contaminated threads should be solvent-cleaned or degreased for maximum strength.

Step 2 – Apply the product

• Shake the bottle briefly.

• Apply a continuous bead of Grade AV to the male thread, covering the full engagement length.

• For blind holes, apply some product into the female thread so it is pushed up through the joint as the fastener is inserted.

Step 3 – Assemble and tighten

• Assemble the parts and tighten to the specified torque.

• Avoid moving or loosening the joint during the first minutes, so the adhesive can fixture.

Step 4 – Allow cure before full load

• Fixture (handling) strength is typically achieved within minutes, but full performance requires up to 24 hours at room temperature, depending on material, gap and temperature.

Step 5 – Disassembly (if ever required)

• As a high-strength red threadlocker, Grade AV generally requires significant force for removal.

• Disassembly is often aided by localised heating of the joint (only if compatible with the base materials and design), followed by use of appropriate hand tools.

Safety & Handling

From Safety Data Sheets and distributor information, typical precautions for Loctite Grade AV include:

• Avoid contact with skin and eyes; may cause irritation or sensitization in some individuals.

• Use in a well-ventilated area; avoid inhaling vapors or mists.

• Wear appropriate PPE such as safety glasses and protective gloves.

• Do not discharge uncured product into drains or the environment.

• Store in a cool, dry place away from heat and direct sunlight, in the original, tightly closed container.

Always refer to the latest Henkel SDS for your country/region before handling or using the product.

FAQs

Q1: When should I choose Loctite Grade AV instead of a blue threadlocker like Loctite 243?
Loctite Grade AV is a high-strength, red threadlocker intended for permanent assemblies, especially large coarse threads. Choose it when you want maximum resistance to loosening and are comfortable that future disassembly may require heat or heavy tools. Medium-strength products like 243 are better when routine service or adjustment is expected.

Q2: What fastener sizes is Grade AV best suited for?
It is commonly used on large, coarse-threaded nuts, bolts and studs, up to around 1″ diameter in typical datasheets. The combination of medium viscosity and high strength makes it ideal for heavy-duty fasteners on industrial machinery and process equipment.

Q3: Can Loctite Grade AV be used for porosity sealing?
Yes. Beyond thread locking, Grade AV is often used to seal porosity in welds, castings and powdered metal components, helping eliminate weepage of oils, fuels and other low-viscosity fluids through micro-pores.

Q4: Is Loctite Grade AV removable?
It is categorized as a high-strength, “permanent” threadlocker. This means fasteners normally cannot be removed with small hand tools alone and may require extended lever arms or heating of the joint to soften the adhesive. For joints that must be regularly dismantled, a medium-strength threadlocker is usually recommended instead.

Q5: Does Grade AV require a primer?
On active metals like carbon steel and some brass, Loctite Grade AV typically cures well without a primer. On more passive surfaces (e.g., certain stainless steels or heavily plated parts) or at low temperatures, a Loctite primer/activator can be used to speed up cure and improve consistency. Always follow Henkel’s latest recommendations for your specific substrate and environment.

Q6: Can I use Loctite Grade AV on plastic threads?
No. Grade AV is formulated for metal-to-metal joints. Anaerobic threadlockers can cause stress cracking in some plastics and typically will not cure properly on non-metallic substrates. For plastic or mixed-material connections, use a product specifically designed for plastics.

Q7: How do storage conditions affect shelf life?
Exposing the product to high temperatures or direct sunlight can shorten shelf life and affect viscosity and cure speed. Store unopened bottles in a cool, dry location in line with Henkel’s guidance. Do not return unused material from a contaminated nozzle to the bottle to avoid premature curing inside the container.