Loctite 515 Flange Sealant – Flexible Form-in-Place Gasket

Loctite 515 is a purple, one-part anaerobic gasket sealant for close-fitting, rigid metal flanges. It cures between mating metal surfaces to form a flexible seal that accommodates small flange movements.

Key benefits

• Forms a gasket in place without mixing.
• Thixotropic consistency helps control application.
• Seals closely machined metal flange joints.
• UV fluorescence helps check product coverage.

When to use

Suitable industrial applications include pumps, thermostats, compressors, transmission housings and axle covers with rigid, machined metal faces. Maximum catalog gap fill is 0.25 mm (0.01 in).

Technical specifications

• Chemistry: methacrylate ester acrylic; anaerobic cure.
• Color: dark purple, opaque; specific gravity: 1.1 at 25°C.
• Viscosity: 700,000–1,700,000 mPa·s at 25°C, Brookfield HBT, spindle TB, 0.5 rpm.
• Typical lap shear strength: 6 N/mm² on grit-blasted steel after 24 hours at 22°C (ISO 4587).
• Catalog fixture time: approximately 30 minutes.

Application and cure

Clean and degrease both mating faces. Apply a continuous bead to one flange, encircling bolt holes, then assemble and tighten promptly. Cure rate varies with substrate, gap, temperature and activator. Consult the technical data sheet when an activator is needed for passive metals or slow cure. Fixture time is not full cure; establish adequate cure before returning the assembly to service.

Storage and limitations

Store unopened in a dry location, ideally at 8–21°C. Not recommended for pure oxygen, oxygen-rich service or strong oxidizers. Test plastic compatibility before use. For industrial use only; Henkel states this product is not intended for consumer sale or use. Follow the SDS: avoid exposure, use ventilation and suitable skin and eye protection. This product can cause serious eye damage. WARNING: Cancer and reproductive harm — www.P65Warnings.ca.gov.

Henkel technical data sheet