Features and Benefits

LOCTITE 638 is a high strength, fast curing, general purpose retaining compound.

LOCTITE 638 is designed for the bonding of cylindrical fitting parts, particularly with narrow bond gaps approaching 0.25 mm. The product cures when confined in the absence of air between close-fitting metal surfaces and prevents loosening and leakage due to shock and vibration. It not only works on active metals but also on passive substrates, exhibiting robust cure performance. The product offers high-temperature performance and good oil tolerance, and tolerates minor surface contaminants.


Ideal for shafts, gears, pulleys and similar cylindrical parts

High strength on all metals, including passive substrates (e.g. stainless steel)

High temperature resistance

Tolerates minor contaminants, including industrial oils

DVGW Approval (EN 751-1): NG-5146AR0619

Technical Information

Agency approvals / certificates / specifications DVGW (EN 751-1): NG-5146AR0619, NSF P1 Reg No: 123010, WRAS (BS 6920): 0511518
Application method Dispense System, Manual
Applications For Close Fitting Cylindrical Parts, For Slip Fitted Parts, Retaining
Colour Green
Cure type Anaerobic Cure
Fixture time 4.0 min.
Gap fill 0.15 - 0.25 mm
Key characteristics Fluorescent, Oil Tolerant, Strength: High Strength, Temperature Resistant, Viscosity: High Viscosity
Operating temperature -55.0 - 180.0 °C (-65.0 - 355.0 °F )
Physical form Liquid
Recommended for use with Metal: Steel
Shear strength, Steel 31.0 N/mm² (4500.0 psi )
Viscosity 2500.0 mPa·s (cP)

Documents and Downloads

 Technical Data Sheet