WEICON WEICONLOCK AN 302-40 Anaerobic Thread Sealant

Weicon WEICONLOCK AN 302-40 is an anaerobic solution designed for threaded connections to both prevent loosening and provide sealing, serving as an industrial adhesive and thread-sealing compound. Its transparent appearance makes post-application visual inspection easier, and its medium viscosity supports controlled dispensing onto threads. It cures to a medium-strength bond, allowing assemblies to be dismantled with standard hand tools when required. The product offers a reliable approach to locking and sealing, especially in installations where vibration-related loosening is a concern.

Technical description and operating principle of WEICONLOCK 302-40

AN 302-40 functions as an anaerobic, resin-based industrial adhesive that cures in narrow gaps between metal surfaces once contact with air is cut off. This structure fills the clearances in threaded joints, limits micro-movements, and simultaneously forms a sealing barrier. It is transparent and may offer fluorescent traceability, which can be advantageous for inspection processes. It is recommended for threaded connections up to M20 (R 3/4”) and has a maximum gap-filling capability of 0.15 mm. Manufacturer: WEICON GmbH & Co. KG (Germany).

Curing behavior, strength, and resistance characteristics

At +20 °C, the product is a medium-viscosity formulation with a Brookfield viscosity of approximately 600 mPa·s. Typical initial fixture/handling strength is achieved within 10–20 minutes, and full strength is reached within 3–6 hours. For threaded joints, the breakaway torque is specified at 12–16 Nm and the prevailing torque at 18–24 Nm, aligning with the practical serviceability expectations of the medium-strength class. Shear strength is reported as 8–12 N/mm² according to DIN 54452. The temperature resistance range is -60 °C to +150 °C, making it suitable for common operating conditions found in many machines and process lines.

Surface preparation and application method

For best results, thread surfaces should be free from oil, dirt, and loose oxides; light roughening may be used if needed. Application is carried out by dispensing around the thread with the nozzle, then quickly assembling the parts and tightening to the appropriate torque; for blind threaded holes, a sufficient amount should also be applied into the hole. Avoiding direct metal contact with the dispensing nozzle and not returning product that has contacted metal back into the container are critical to prevent premature curing inside the package. For passive metals, low temperatures, or difficult-to-cure assemblies, the manufacturer may recommend using a curing accelerator/activator as an accessory.

Sealing and vibration resistance performance with AN 302-40

Because it fills capillary gaps between threads, this product addresses both loosening and leakage risks together. Under vibration, impact, and thermal expansion effects, it helps reduce self-loosening of threaded connections. Its DVGW registration/approval indicates that it is intended for gas-sealing applications, which can be an important selection criterion in facilities with strict maintenance standards. The transparent, medium-viscosity structure supports clean application discipline and overflow control after assembly. For these reasons, it can be positioned as an industrial adhesive solution that combines bolt locking and thread-sealing requirements in a single product.

Industry-specific applications and compatible surfaces

AN 302-40 can be used in machine manufacturing for gearbox joints, coupling elements, auxiliary threaded connections on flanged equipment, and vibration-prone constructions requiring joint security. In the energy and process industries, it contributes to thread sealing in gas lines, compressed-air systems, and valve/fitting connections. In automotive and heavy-duty applications, it may be preferred to reduce loosening risk in auxiliary engine-area joints, chassis equipment, and assemblies exposed to service vibration. In pump, compressor, and hydraulic/pneumatic systems, typical uses include improving leak control at threaded points and stabilizing maintenance intervals. The product is developed primarily for metal threaded connections; performing a small-scale test before application is good practice for confirming surface compatibility and process approvals.

Key advantages, storage, and operational notes

Its medium-strength profile provides joint security while maintaining service removability, which is a significant advantage in maintenance operations. The gap-filling capability helps block micro-leak paths and delivers more stable results against minor assembly tolerance deviations. The product can be stored for at least 24 months at room temperature in its unopened original packaging, and it should be protected from heat sources and direct sunlight. Clean surface practice, correct dosing, and avoiding movement of the assembly during the initial curing phase are critical steps for repeatable performance. From an occupational safety standpoint, using appropriate PPE and following on-site SDS instructions should be part of standard operating practice for chemical products.