LOCTITE® 640

Features and Benefits

Low-viscosity, high-strength retaining compound with good temperature resistance. Slow cure time makes it ideal for parts that need longer positioning time, such as large diameter parts or those made of active metals, such as brass.
LOCTITE® 640 is ideal when you need a retaining compound for parts that require a longer positioning time, such as large diameter parts or those made of active metals, such as brass. This high strength adhesive has a typical fixture time on steel of 2 hours, and a service temperature of -67°F to 347°F (-55°C to 175°C) when fully cured. The product's maximum diametrical clearance is 0.1 mm (0.0004"), and it fluoresces when exposed to UV light - great for quality control. Perfect for retaining keys and splines, eliminating backlash in worn assemblies, retaining bearings in place and preventing spin out, retaining rotor to shafts in fractional and subfractional horsepower motors, retaining bushings and sleeves in housings and on shafts, augmenting press fits, and restoring the fit to worn assemblies or out of tolerance parts. Also used for Mil-R-46082 military specifcation related applications.
  • Slow curing for long assembly time
  • Ideal for large diameter components
  • High strength
  • Good temperature resistance
  • Meets Mil Spec: Mil-R-46082
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Technical Information

Chemical basis / base Methacrylate
Color Green
Diametrical clearance <0.1 mm
Fixture time 2.0 hr.
Recommended for use with Metal: Steel
Shear strength 22.0 N/mm²
Viscosity, Falling Ball 'D' @ 25.0 °C 450.0 - 750.0 mPa·s (cP)