WEICON WEICONLOCK® AN 305-77 Anaerobic Thread Sealant 50 ml (Yellow)

Weicon WEICONLOCK® AN 305-77 Anaerobic Thread Sealant 50 ml (Yellow) is a single-component product that cures anaerobically and is developed to provide sealing on metal pipe threads and flange surfaces. It hardens in the oxygen-deprived zone of metal-to-metal contact, creating both a sealing and locking effect along the joint line. Its yellow, fluorescent formulation makes visual inspection of the application line easier. The product is manufactured by WEICON GmbH & Co. KG, Germany.

Reliable Sealing on Pipe Threads with WEICONLOCK AN 305-77
AN 305-77 is a solution focused on reducing leak risk in pipe threads and metal connection points, and in many assembly scenarios it is considered among anaerobic sealing products in the industrial adhesive category. With its medium-strength profile, it supports connection security while aiming to preserve the ability to be dismantled with standard hand tools when servicing is required. Its high viscosity helps the material stay in the thread roots without running or spreading, supporting continuity of the sealing line. For use on large-diameter line components, an application range up to M80 / R 3″ is specified for threaded connections.

Anaerobic Chemical Base and Performance Features
This product cures between metal surfaces as a methacrylate-based anaerobic industrial adhesive/sealant compound and focuses on forming a more uniform film layer compared to conventional sealing fillers. As the gap-bridging capacity is specified as a maximum of 0.5 mm, it contributes to sealing by filling thread gaps within suitable tolerances. The specified operating temperature range of -60 °C to +150 °C helps planning for use both in cold lines and around installations exposed to temperature fluctuations. With viscosity defined at 24,000–70,000 mPa·s at 25 °C, it supports controlled application, especially on larger thread profiles.

Application Method and Managing the Curing Process
For the most stable results, it is recommended that surfaces are clean and free from oil; good surface preparation directly affects the continuity of the sealing line. The product is applied evenly around the thread in a circular motion using the dispensing tip, and it is advised not to let the tip come into direct contact with the metal. The pipe thread is tightened to the desired alignment; for flange sealing, a continuous bead is applied to one flange face and the parts are joined quickly. The stated handling strength at room temperature of 15–30 minutes and the development of final strength within 1–3 hours help structure commissioning plans correctly.

Sector-Based Applications and Compliance Information
AN 305-77 can be preferred to strengthen the sealing of metal threaded connections in process piping, HVAC connections, building services, and industrial maintenance/repair assemblies. It helps reduce leak risk triggered by vibration and pressure fluctuations in pump, valve, filter, and measuring equipment connections, while also providing a locking effect that limits loosening through an industrial adhesive approach. The product is positioned as “DVGW approved,” which is important for projects requiring suitability assessment in drinking water applications. In addition, being identified in supply systems with ISSA and IMPA codes can facilitate logistics processes in marine and industrial service operations.