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LOCTITE® 515™ is an anaerobic flange sealant that cures between close-fitting metal surfaces in the absence of air. It seals rigid metal joints, flexes with minor flange movements, and provides low-pressure resistance immediately after assembly. Ideal for pumps, thermostats, compressors, transmission housings, and axle covers.
Product Description
LOCTITE® 515™ is a high-viscosity anaerobic flange sealant that cures when confined between close-fitting rigid metal faces, forming a form-in-place gasket rather than relying on a cut gasket sheet. Once cured, it seals the joint while still flexing slightly with minor flange movement, and it provides resistance to low pressures immediately after assembly — before the anaerobic cure has fully developed. That makes it a common choice for pumps, thermostats, compressors, transmission housings, and axle covers. Compared to LOCTITE® 573™, which is a medium-viscosity thixotropic paste for similar flange applications, 515™ runs much thicker (700,000–1,700,000 mPa·s), which suits wider or more irregular flange gaps rather than tightly controlled surfaces. It carries UL Classification MH8007 and Australian Gas Association approval for use with gasoline, petroleum oils, natural gas, butane, and propane.
| Technology | Acrylic | |
| Chemical Type | Methacrylate ester | |
| Appearance(uncured) | Opaque, dark purpleLMS | |
| Fluorescence | Positive under UV lightLMS | |
| Components | One component - requires no mixing | |
| Viscosity | High | |
| Cure | Anaerobic | |
| Application | Sealing |
Bond surfaces should be clean and free from grease. 515™ is designed for close-fitting flanged parts with gaps up to 0.25 mm, applied manually as a continuous bead or by screen printing to one flange surface. Low pressure testing (under 0.05 MPa) can confirm a complete seal immediately after assembly and before full cure. Flanges should be tightened as soon as possible after assembly to avoid shimming.
LOCTITE® 515™ is not recommended for pure oxygen or oxygen-rich systems, or as a sealant against chlorine or other strong oxidizers, and is not normally recommended for use on plastics — particularly thermoplastics where stress cracking could occur.
Store in the original, unopened container in a dry location. Optimal storage is 8°C to 21°C — storage below 8°C or above 28°C can affect product properties. Material removed from the container should not be returned to it once it may have been contaminated during use.
This page summarizes performance data only. Consult the Safety Data Sheet (SDS) for full handling, storage, and safety information before use.
LOCTITE® is a trademark of Henkel Corporation in the U.S. and elsewhere.
We cooperate with multiple well-known domestic suppliers
Our products have passed various industry certifications
