loctite 680

Loctite 680

Loctite 680 is a retaining compound suitable for large clearance fits and is used for bonding cylindrical mating parts, especially those with a clearance of up to 0.25 mm. It is well suited for components subjected to high dynamic forces or cyclic loads, such as shafts, gears, pulleys and cylindrical parts.

Application method:Dispense system, Manual, Pressure
Applications:For loose fitting parts, For slip fitted parts, Retaining
Color:Green
Cure type:Anaerobic cure
Fixture time:4.0 min.
Full cure time, @ 22.0 °C:24.0 hr.
Key characteristics:Fluorescent, Oil tolerant, Primerless, Strength: high strength
Number of components:1 part
Physical form:Liquid
Recommended for use with:Metal
Shear strength, Steel:4000.0 psi
Specific gravity, @ 25.0 °C:1.1
Viscosity, Brookfield – RVT, @ 25.0 °C Spindle 3, speed 20 rpm:750.0 – 1750.0 mPa·s (cP)
Viscosity, cone & plate, @ 25.0 °C Shear Rate 129 s⁻¹:650.0 – 1850.0 mPa·s (cP)

Product Overview

Loctite 680 is a high-strength, green anaerobic retaining compound formulated for bonding cylindrical components, especially when a low-viscosity adhesive is preferred. It delivers reliable performance against loosening and leakage caused by vibration or shock and cures effectively on both active metals, such as mild steel, and passive surfaces like stainless steel or plated parts. The formulation also tolerates light oil contamination and does not require a primer or additional surface treatment.

Key Benefits:

  • Low viscosity for easy application

  • NSF/ANSI 61 certified up to 82°C (179.6°F)

  • High-strength and robust curing performance on inactive surfaces without primer

  • Tolerates minor surface contamination

  • Fluorescent under UV for quality control

Technical Specifications

PropertyDescription
ColorGreen
StrengthHigh
Viscosity750–1750 mPa·s (Brookfield RVT)
Fixture Time (Steel)4.0 minutes
Full Cure Time24 hours
Service Temperature RangeUp to 82°C (179.6°F)
Shear Strength (Steel)4000 psi
Specific Gravity1.1
Cure TypeAnaerobic
Primer RequirementNone

Typical Applications

Loctite 680 is ideal for bonding cylindrical fitting parts, especially where low viscosity is required. Typical applications include:

  • Securing gears, pulleys, and sprockets on shafts

  • Bonding bushings, bearings, and sleeves into housings

  • Fixing rotors to electric motor shafts

  • Suitable for components subjected to high dynamic forces or cyclic loads

Application Instructions

  1. Clean all parts thoroughly with Loctite® SF 7063 or an approved cleaner.

  2. Apply Loctite 680 to the shaft and the bore surface.

  3. Assemble parts quickly to ensure uniform coverage.

  4. Remove any excess adhesive.

  5. Allow curing at room temperature (full cure in 24 hours).

Note: For faster curing, moderate heat (up to 80°C) can be applied.

Performance & Compatibility

  • Works effectively on steel, stainless steel, and aluminum

  • Resistant to oil contamination and industrial fluids

  • Withstands vibration, dynamic loads, and impact

  • Suitable for press-fit and slip-fit cylindrical assemblies

Storage & Shelf Life

  • Store unopened containers between 8°C and 21°C (46°F–70°F)

  • Avoid direct sunlight and moisture exposure

  • Shelf life: 24 months (in original packaging)

FAQs

Q1: What is the difference between Loctite 680 and Loctite 638?
A1: Loctite 680 offers lower viscosity and is suitable for larger clearance fits, while Loctite 638 provides higher strength and is ideal for narrow gap assemblies.

Q2: Can Loctite 680 be used on stainless steel?
A2: Yes, it performs effectively on both active and passive metals, including stainless steel.

Q3: Does Loctite 680 require heat to cure?
A3: No, it cures at room temperature but can be accelerated with moderate heat if needed.

Q4: How do I remove cured Loctite 680?
A4: Apply localized heat above 250°C and use mechanical removal or a Loctite solvent like 7200 Gasket Remover.

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