Loctite? Gasket Maker 515? Flange Sealant is a flexible, gasketing material for use on rigid machined flanges with less than 0.015″gap. OEM approved use where OEs specify 515 or gasket (cures in absence of air). Eliminates preformed, pre-cut, paper, rubber and cork gaskets.

Sealant for Gasketing
Gasketing is a sealant between two flanges assembled with screws. The sealant completely fills the space between the flange surfaces, thereby preventing the escape of gaseous or fluid materials in composite machine parts or pipe connections.
The sealant for gasketing can be used with many different types of materials including various metals, wood, plastic, rubber, ceramics, glass, and even concrete. The type of sealant selected for a specific application depends on the material to be sealed, environmental conditions, temperature, and operating pressures in the system.