LOCTITE 518
Harmonization Code : 3506.91.90.99 | Prepared glues and other prepared adhesives, not elsewhere specified or included; products suitable for use as glues or adhesives, put up for retail sale as glues or adhesives, not exceeding a net weight of 1 kg ; Adhesives based on polymers of headings 3901 to 3913 or on rubber; Other ; Other

Main features
- Anaerobic Thread Sealing
- Gap-Filling Sealant Formulation
- Thixotropic Application Control
Product Description
LOCTITE® 518™ is a single-component, medium-strength anaerobic flange sealant formulated for close-fitting rigid metal surfaces. The thixotropic red acrylic material cures when confined between mating metal faces in the absence of air and provides resistance to low pressures immediately after flange assembly. It seals gaps up to 0.25 mm and tolerates minor surface contamination from oils, including lubricating, anti-corrosion, and protection fluids. Typical uses include form-in-place gasketing of rigid metal flanges and casings, such as gearbox and engine assemblies.
Key features
- Anaerobic flange sealing: Cures between close-fitting metal surfaces when isolated from air.
- Gap-filling capability: Designed for flanged parts with gaps up to 0.25 mm.
- Thixotropic consistency: Helps limit migration of the uncured material after application.
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Physical Properties
Thermal Properties
Mechanical Properties
Additional Information
As-supplied / before-processing properties
Typical properties of the uncured material; values are reference data rather than guaranteed product specifications.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Technology | Acrylic | — | Uncured material |
| Chemical type | Dimethacrylate ester | — | Uncured material |
| Appearance | Red gel-like material | — | Uncured material |
| Fluorescence | Positive | — | Under ultraviolet light |
| Specific gravity | 1.1 | — | At 23°C |
| Viscosity | 4,000,000 | mPa·s | Brookfield HBT, 25°C; spindle TC, 0.5 rpm, Helipath |
After-processing / final-state properties
Typical cured-material properties depend on the stated cure schedule, substrate, specimen, and test method.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Glass-transition temperature | 100 | °C | ISO 11359-2; cured 24 hours at 23°C |
| Elongation at break | 64 | % | ISO 527-2; cured 24 hours at 23°C |
| Tensile strength | 7.3 | N/mm² | ISO 527-2; cured 24 hours at 23°C |
| Tensile modulus | 54 | N/mm² | ISO 527-2; cured 24 hours at 23°C |
| Compressive shear strength | 5 | N/mm² | ISO 10123; steel pins and collars; cured 24 hours at 23°C |
| Lap-shear strength | 8.4 | N/mm² | ISO 4587; grit-blasted mild steel; cured 24 hours at 23°C |
| Maximum sealed induced gap | 0.25 | mm | Annular gasket; mild steel or aluminum; cured 20 hours at room temperature |





















