WEICON WEICONLOCK® AN 305-86 Anaerobic Thread Sealant is a single-component, anaerobically curing adhesive/sealing compound designed to seal metal threaded connections and flange faces. It hardens in the confined area between metal surfaces where contact with air is cut off, creating a high-strength locking and sealing effect. Its high-viscosity consistency enables controlled filling in thread roots and helps manage flow during application. The product is developed by WEICON GmbH & Co. KG, Germany.

Sealing Threaded and Flange Connections with AN 305-86
AN 305-86 is positioned as an industrial adhesive type product focused on preventing leaks, especially on pipe threads and metal connection points, and it is classified in a “high-strength” category that is difficult to disassemble. It is specified for use on threaded connections up to M56 / R 2″. The high viscosity helps the material remain in the joint line during application, supporting continuity of the sealing line. This approach combines sealing with industrial adhesive use, particularly at installation points exposed to vibration, pressure fluctuations, and thermal expansion.

Anaerobic Chemical Base and Curing Principle
The product is a methacrylate-based anaerobic adhesive/sealant system, and curing takes place in the oxygen-deprived area between metal surfaces. Through this mechanism, a high-strength polymer network is intended to form in the joint line after application. Its characterization as “slightly soluble” in water supports the expected durability approach for sealing installations. Since it contains components that initiate the reaction, preventing skin and eye contact and working in well-ventilated areas are important.

Performance Parameters and Resistance Range
For AN 305-86, temperature resistance is specified as -60 °C to +150 °C, supporting use scenarios both in cold lines and around equipment exposed to temperature changes. The gap-filling capacity is defined as a maximum of 0.3 mm, helping keep the sealing line stable within suitable thread tolerances. Viscosity is stated in the range of 6,000–7,000 mPa·s, enabling controllable application particularly on larger-diameter threads. For threaded connections, the breakaway torque is specified as 15–30 Nm and the prevailing torque as 25–45 Nm; therefore, its “difficult-to-remove” nature should be considered in maintenance scenarios where disassembly is required.

Pressure Resistance and Application Limits
In pipe and thread sealing applications, a pressure resistance value up to 1,500 bar is specified for M3–M4 sizes based on free-cutting steel and an 8.8 grade clamping screw reference; as the size increases, this value decreases stepwise. This supports evaluating the product for high-pressure line components, but it should be considered together with line design, thread standard, and assembly torque. Handling strength at room temperature is defined as 60–90 minutes, and final curing time as 12–24 hours; commissioning plans should take these times into account. The material is red, which can provide a practical advantage for visual inspection and application tracking.

Application Method and Sector-Based Use Areas
Cleaning surfaces from oil, dirt, and process residues before application directly affects sealing and industrial adhesive performance. The product is applied evenly around the thread using the dispensing tip; it is recommended not to let the dispensing tip contact the metal directly. The connection is tightened to the desired alignment, and for flange sealing, a continuous bead is applied to one surface and the parts are joined quickly. Typical use areas include hydraulic and pneumatic line connections, process piping systems, pump/valve connections, compressor-related installations, industrial maintenance and repair, and machine manufacturing assemblies—especially where reducing leak risk and limiting loosening in metal threaded joints is required.