LOCTITE® 638™ is designed for the bonding of cylindrical fitting parts, particularly where bond gaps can approach 0.25 mm and where maximum strength at room temperature is required. The product cures when confined in the absence of air between close fitting metal surfaces and prevents loosening and leakage from shock and vibration. Typical applications include locking bushings and sleeves into housings and on shafts. LOCTITE® 638™ provides robust curing performance. It not only works on active metals (e.g. mild steel) but also on passive substrates such as stainless steel and plated surfaces. The product offers high temperature performance and oil tolerance. It tolerates minor surface contaminations from various oils, such as cutting, lubrication, anti-corrosion and protection fluids.
FEATURES AND BENEFITS
Prevents loosening: It fills all gaps between the cylindrical components and cures into a hard thermoset plastic. This unitizes the assembly and prevents loosening and leakage from shock and vibration.
Works on all metal substrates.
Tolerant towards minor surface contaminations.
High temperature resistance.
High strength on all metals, including passive substrates (e.g. stainless steel).
APPLICATION
Retaining
PRODUCT CHARACTERISTICS
Technology
Acrylic
Chemical Type
Urethane methacrylate
Appearance (uncured)
Green liquidLMS
Fluorescence
Positive under UV lightLMS
Components
One component – requires no mixing
Viscosity
High
Cure
Anaerobic
Secondary Cure
Activator
Application
Retaining
Strength
High
TYPICAL PROPERTIES OF UNCURED MATERIAL
Specific Gravity @ 25 °C
1.1
Flash Point – See SDS
Viscosity, Brookfield – RVT, 25 °C, mPa·s (cP)
Spindle 3, speed 20 rpm
2,000 to 3,000LMS
Viscosity, Cone & Plate, 25 °C, mPa·s (cP)
Shear rate 129 s -1
1900 to 3100
TYPICAL PROPERTIES OF CURED MATERIAL
Physical Properties:
Glass Transition Temperature ISO 11359-2, °C
76
Coefficient of Thermal Expansion, ISO 11359-2, K ^-1
