Loctite 638 Retaining Compound 50ml

Loctite 638 is a high-strength green retaining compound engineered for maximum efficacy in the bonding of cylindrical fitting parts. This industrial-grade adhesive permanently locks bushings and sleeves into housings and on shafts, preventing costly loosening and leakage caused by shock and vibration. Whether you are securing shafts, gears, or pulleys and similar cylindrical parts, this premium retaining compound provides a robust, leak-proof seal on all metals—including specific difficult materials like passive substrates (such as stainless steel and plated surfaces).

Why Choose Loctite 638?

• Maximum Bonding Strength: Cures when confined in the absence of air between close-fitting metal surfaces to prevent components from loosening and leaking under high mechanical stress.
• Robust Substrate Compatibility: Exhibits exceptional cure performance on both active metals (e.g., mild steel) and passive substrates like stainless steel.
• High Oil Tolerance: Tolerates minor surface contamination from various industrial oils, such as cutting fluids, lubricants, and anti-corrosion protection fluids.
• Ideal for High-Gap Applications: Engineered for maximum efficacy in cylindrical assemblies with narrow bond gaps approaching 0.25 mm.
• Thermal and Chemical Resiliency: Offers high-temperature performance up to 300°F (-65°F to 300°F) and carries extensive global approvals for diverse environments.

Technical Specifications

• Product Type: Anaerobic Retaining Compound
• Strength: High Strength
• Color: Green
• Container Size: 50ml
• Certifications: P1 NSF Reg. No.: 123010, DVGW Approval (EN 751-1): NG-5146AR0619, WRAS Approval (BS 6920): 0511518

Simple Application Instructions

1. Clean: For optimal results, clean all internal and external surfaces with a LOCTITE® cleaning solvent and let dry. To accelerate cure speed or where large gaps are present, apply an activator and allow it to dry.
2. Apply: Apply several drops of the liquid retaining compound to the leading edge of the pin and the inside of the collar (for slip fits), or thoroughly coat both bond surfaces (for press fits).
3. Assemble: Assemble and tighten the parts as required (using a rotating motion for slip fits). The formula will begin curing once confined between close-fitting metal surfaces in the absence of air. Do not disturb parts until handling strength is achieved.

Frequently Asked Questions (FAQ)

What is Loctite 638 used for?

Loctite 638 is a high-strength anaerobic retaining compound designed for the bonding of cylindrical fitting parts, particularly where gaps can approach 0.25 mm. It is specifically formulated to prevent cylindrical components—like shafts, gears, sleeves, and pulleys—from loosening or leaking due to heavy shock, vibration, and thermal loading.

Can Loctite 638 be disassembled?

Yes, but it requires specific methods due to its permanent high-strength nature. If needed, apply localized heat to the assembly to approximately 250°C and disassemble the components while they are still hot. Mechanical aids can be used if this temperature cannot be fully reached.

Does Loctite 638 work on passive substrates?

Yes. Loctite 638 offers robust performance across all metals. Unlike basic anaerobic adhesives, it delivers excellent cure speed and strength on active metals (like mild steel) as well as passive substrates such as stainless steel and plated finishes.

Is Loctite 638 safe for food or plumbing applications?

Loctite 638 is registered to NSF Category P1 for use as a sealant in and around food processing areas where there is no possibility of food contact. It also carries DVGW and WRAS approvals, confirming its testing profile for industrial standards. Note that it is not recommended for pure oxygen, chlorine, or strong oxidizing systems.