Feeling overwhelmed by adhesive choices for your project? You’re certainly in good company. Loctite, a well-respected name in adhesives, offers a wide array.
Today, let’s focus on two popular ones: Loctite 660 and 680. Both are stellar retaining compounds with their own unique traits and best uses.
We’ll examine what sets them apart and what they share, aiming to clarify which could be the perfect match for your needs.
Whether you’re tackling a job with professional rigor or dabbling in a DIY endeavor, picking the right adhesive matters, and we’re here to make that decision a little easier for you.
What is Loctite 660?
Loctite 660 is a silver-colored, high-viscosity retaining compound designed to bond cylindrical fitting parts, especially with significant bond gaps.
Its unique formulation effectively fills gaps between 0.25mm and 0.5 mm. The product is ideal for worn seats, keys, splines, bearings, or tapers without re-machining.
It’s also suitable for retaining shims. This high-strength compound is registered to NSF Category P1, making it safe for certain types of incidental food contact.
Once cured, Loctite 660 offers an impressive shear strength of 3335.0 psi, and it’s operable in temperatures ranging from -65.0 to 300.0 °F.
What is Loctite 680?
Loctite 680 is a green-colored, low-viscosity retaining compound primarily used to bond cylindrical fitting parts. Like Loctite 660, it prevents parts from loosening due to shock or vibration.
However, it stands out because it can fluoresce under UV light, aiding in monitoring component bonding. Loctite 680 is versatile, working well with metals and passive substrates such as stainless steel or plated surfaces.
It’s particularly noted for its high-temperature tolerance and resistance to minor surface contamination from industrial oils. These properties make it suitable for components at risk of high temperatures or fluctuations.
Loctite 680 is available in various sizes and is ANSI/NSF 61 certified for indoor and outdoor water systems up to 82 °C.
How are they different?
• Viscosity and Application: Loctite 660 is a high-viscosity paste, ideal for filling more significant gaps and bonding worn parts without re-machining. In contrast, Loctite 680 is a low-viscosity compound better suited for applications where the risk of uncured adhesive running is a concern.
• UV Fluorescence: Loctite 680 has the unique feature of fluorescing under UV light, which is not mentioned for Loctite 660. This characteristic helps in monitoring the application and curing process.
• Color and Consistency: Loctite 660 is described as a silver-colored paste, while Loctite 680 is a green-colored compound. This color difference might aid in visual differentiation during application.
• Certification: Loctite 680 is ANSI/NSF 61 certified, making it suitable for specific water system applications, a certification not mentioned for Loctite 660.
How are they similar?
• Primary Use: Both are designed to bond cylindrical fitting parts and effectively prevent loosening due to shock or vibration.
• Temperature Resistance: Both compounds offer high-temperature resistance, making them suitable for components exposed to temperature fluctuations.
• Compatibility with Metals: They work well with metals and passive substrates like stainless steel or plated surfaces, showing versatility in their application across various materials.
• Resistance to Contamination: Both Loctite 660 and 680 are tolerant to minor surface contamination from industrial oils, enhancing their durability and effectiveness in diverse environments.
What’s better about Loctite 660?
Loctite 660’s high viscosity and ability to fill more significant gaps make it particularly beneficial for repairing worn parts without re-machining. Avoiding replacing or reconditioning parts can result in substantial savings in both time and cost.
Its high shear strength ensures a robust bond, making it suitable for high-stress applications. The silver color provides a distinct visual cue during application.
What’s better about Loctite 680?
Loctite 680’s low viscosity makes it ideal for applications with a thinner compound to prevent running. Its ability to fluoresce under UV light aids in quality control, ensuring proper application and cure.
The ANSI/NSF 61 certification expands its usability to include specific water system applications, offering a broader range of uses. Additionally, it’s available in various sizes, providing flexibility based on the project’s scale.
Who should get Loctite 660 (and why)?
Individuals or industries dealing with worn or damaged cylindrical parts, like bearings or keyways, will find Loctite 660 particularly beneficial.
Its high viscosity and gap-filling properties are ideal for applications involving more significant gaps or worn surfaces. Those looking for a robust solution for high-stress environments will also appreciate its high shear strength and temperature resistance.
Who should get Loctite 680 (and why)?
Loctite 680 suits those needing a lower viscosity compound that won’t run during application, making it ideal for intricate or vertical surfaces.
Its UV fluorescence benefits applications where monitoring and quality control are crucial. Industries dealing with water systems may prefer Loctite 680 due to its ANSI/NSF 61 certification, ensuring safety and compliance in such environments.
Final Thoughts
When deciding between Loctite 660 and 680, consider your project’s needs. Loctite 660 is great for fixing worn parts, and its strong bonding for more significant gaps makes it perfect for repairs.
On the other hand, Loctite 680’s low viscosity and UV fluorescence make it precise and easy to check, suitable for various tasks.
Both handle high temperatures and work with many materials. Your choice should match the parts, environment, and how long you need the bond to last.