Loctite 263

LOCTITE 263 is a one-component, high strength anaerobic threadlocking adhesive formulated using dimethacrylate ester technology. The uncured material is red in color and exhibits fluorescence under UV light for inspection verification. It is designed with medium viscosity and thixotropic behavior to minimize product migration after application. The adhesive cures when confined between close-fitting metal surfaces in the absence of air. It is particularly suitable for applications where disassembly is not required under normal service conditions. For accelerated curing on inactive metals or at low temperatures, activators such as 7471™ or 7649™ may be used.

The product has a specific gravity of approximately 1.1 at 25°C. Brookfield viscosity at 25°C using RVT spindle 3 at 20 rpm typically ranges between 400 and 600 mPa·s (cP). The curing speed depends on the substrate material, bond gap, and ambient temperature. On active metals like steel and brass, fixture time is typically achieved within minutes at room temperature, while passive substrates such as stainless steel may require longer curing time unless an activator is applied.

After full cure at 24 hours and 23°C, LOCTITE 263 demonstrates excellent mechanical strength properties. Breakaway torque performance according to ISO 10964 on M10 black oxide steel nuts and bolts typically reaches around 33 N·m (290 lb·in). Prevail torque at 180° rotation is approximately 26 N·m (230 lb·in). On stainless steel fasteners, breakaway torque typically reaches around 23 N·m (200 lb·in), demonstrating strong holding capability across different metals. The product provides high shear strength when tested according to ISO 10123 on steel pins and collars.

The adhesive maintains strong performance across a wide temperature range. The operating temperature range extends from -55°C to +180°C. The glass transition temperature is approximately 120°C. The coefficient of thermal expansion below Tg is approximately 80 × 10⁻⁶ K⁻¹ and above Tg approximately 150 × 10⁻⁶ K⁻¹. Thermal conductivity is approximately 0.1 W/(m·K), ensuring stable mechanical properties under temperature variation.

LOCTITE 263 offers excellent environmental resistance after full cure. When exposed to motor oil, brake fluid, gasoline, ethanol blends, water/glycol mixtures, and various industrial chemicals, the product retains a high percentage of its original strength after extended aging. Testing under elevated temperatures shows strong retention of locking capability, making it suitable for automotive, heavy machinery, pump, gearbox, and industrial equipment applications. The adhesive resists vibration, shock, and thermal cycling, preventing loosening of critical fasteners.

For proper application, all surfaces should be cleaned and degreased using an appropriate LOCTITE cleaner and allowed to dry. For through holes, apply several drops to the bolt at the nut engagement area. For blind holes, apply the product to the lower third of the internal threads or to the bottom of the hole. In sealing applications, apply a continuous 360° bead to the leading threads of the male fitting while leaving the first thread free. Assemble and tighten to the required torque immediately after application. Larger thread sizes may require product application on both mating surfaces.

Disassembly of LOCTITE 263 bonded fasteners typically requires localized heat to approximately 250°C to soften the adhesive before removal using standard hand tools. Cured residue can be removed mechanically after applying a suitable solvent.

The product should be stored in unopened containers in a dry area at temperatures between 8°C and 21°C. Storage outside the recommended range may affect product performance. Contaminated material should not be returned to the original packaging. The technical values provided are typical laboratory data obtained under controlled conditions of 23±2°C and 50±5% relative humidity and are intended as guidance for industrial use. Users are advised to conduct performance testing under actual production conditions to confirm suitability.