Loctite  518 hardens in the absence of air between closely fitting metal surfaces. It is an anaerobic flange sealant designed for use on rigid iron, aluminum, and steel flanged mating surfaces. 

It fills gaps up to 0.25mm and forms a flexible, chemical-resistant seal that will not tear or decay. 

Parts disassemble easily, even after extended use. Typical applications include sealing close-fitting joints between rigid metal surfaces and flanges. 

It is also used as a form-in-place gasket on rigid flange connections, e.g., transmission systems and engine housings.

• Semi-flexible, medium-strength anaerobic flange sealant
• For active and inactive rigid metal flanges
• Cures even on slightly contaminated surfaces
• Adapts to flange surface irregularities and gaps up to 0.25mm
• Gel texture
• Seals instantly at low pressures
• Reduces storage costs – no need for inventory of pre-cut gaskets of various sizes
• Withstands high pressures when fully cured
• No compression or alignment of flanges required
• Easily automated
• Reduces machining costs – eliminates hand-assembling of conventional gaskets