WEICON Black Seal Liquid Gasket

WEICON Black Seal Liquid Gasket is a special, moisture-curing silicone sealant used for sealing and bonding, particularly in joints with heavy exposure to oil and grease. Thanks to its one-component structure, it can be applied without mixing and is designed to form a permanently elastic gasket bead on the surface. The black film makes it easier to visually track the application line and supports post-assembly inspection. The manufacturer is WEICON GmbH & Co. KG, and the company’s headquarters are stated to be in Germany.

Oil- and grease-resistant sealing with Black Seal liquid gasket
The main purpose of this product is to create a flexible sealing line that reduces the risk of leaks by filling micro-gaps in threaded or flanged connections, cover surfaces, and housing joints. The emphasis on resistance to oil and grease provides a clear selection rationale for fluid-contact scenarios commonly found in automotive and industrial maintenance environments. Since it is intended to maintain elasticity rather than harden and become brittle like some sealing types, it offers practical advantages in assemblies exposed to vibration and thermal expansion. The fact that it is not paintable requires planning in applications where an aesthetic topcoat is needed.

Material structure and basic performance framework
It is defined as a one-component, polysiloxane (acetate)-based, pasty material; this supports drawing a controlled bead by limiting run-off during application. Because it cures with moisture, ambient humidity directly influences curing behavior under installation conditions, and curing time may increase in thick applications. The stated curing progress of about 2–3 mm in the first 24 hours and a skin formation time of about 7 minutes are important for managing the timing of joining parts. With a maximum joint width of 25 mm and gap-bridging capability of up to 5 mm, the product should be evaluated as a joint and surface sealing material rather than a “large gap filler.”

Heat resistance, mechanical flexibility, and standards information
Temperature resistance is stated as -60 °C up to +280 °C for short periods (about 2 hours) and up to +300 °C for short periods, providing a framework for application planning in areas exposed to thermal loads. Values such as approximately 500% elongation at break and a maximum movement accommodation of 15% support a performance approach aimed at keeping the sealing line functional under dynamic effects without cracking. The DIN 4102 B2 building material class and the presence of ISSA/IMPA codes for procurement/specification matching can offer practicality in specification and purchasing processes.

Application method, surface preparation, and sector-based use areas
Before application, surfaces are expected to be clean, dry, and free of oil; residues of oil, grease, and dirt can weaken adhesion and sealing integrity. Application can be carried out with a cartridge gun, pneumatic gun, or automatic dosing systems; it is also stated that in the 200 ml Presspack packaging, flow can be controlled via a min–max adjustment on the cap. Joining the parts before skin formation supports better wetting and contact quality, helping maintain continuity of the sealing line. Typical use areas include transmissions, valve and housing covers, oil pans, water pump connections, flanges, as well as tanks and containers—providing broad applicability in automotive, machine manufacturing, process equipment, and general industrial maintenance.