LOCTITE® 518 Gasket Sealant
Features and Benefits
This general purpose, semi-flexible anaerobic-curing gasketing product is ideal for sealing close fitting, rigid machine flanges made of aluminum, iron or steel.
LOCTITE® 518 is a general purpose, primerless, semi-flexible, form-in-place anaerobic flange sealant. It cures – even in the presence of minor surface contaminants – to seal close fitting joints between rigid metal flanges, and will flex with minor flange movements. It provides resistance to low pressures immediately after assembly of flanges, and is ideal for use on aluminum substrates where you need very good flexibility. Typically used as a form-in-place gasket for pumps, thermostats, compressors, transmission housings and axle covers, it not only works on active metals (e.g. mild steel) but also on passive substrates, such as aluminum with a low copper content. You can expect gap performance to 0.25 mm (0.01").
- Semi-flexible anaerobic flange sealant
- Adapts to surface irregularities & gap fill up to 0.25mm (0.01")
- Forms an instant low-pressure seal
- Cures on inactive surfaces without primer
- NSF registered
Documents and Downloads
Looking for a TDS or SDS in another language?
Technical Information
| Application method | Dispense system, Manual |
| Applications | Rigid assembly gasketing, Sealing |
| Chemical basis / base | Dimethacrylate ester |
| Color | Red |
| Cure type | Anaerobic cure |
| Fixture time, Steel | 25.0 min. |
| Gap fill, Unprimed | 0.25 mm |
| Key characteristics | Fluorescent, For machined, rigid flanges, Immediate low pressure sealing, Strength: medium strength, Surface contamination-tolerant, Thixotropic |
| Number of components | 1 part |
| Operating temperature | -55.0 - 150.0 °C (-65.0 - 300.0 °F ) |
| Physical form | Gel |
| Recommended for use with | Metal: aluminum, Metal: iron - cast iron, Metal: passive metal, Metal: steel |
| Specific gravity, @ 25.0 °C | 1.1 |
| Storage temperature | 8.0 - 21.0 °C |
| Viscosity | 750000.0 mPa·s (cP) |
How to
Step by Step Guide
1. Preparation - Cleaning
Apply LOCTITE® SF 7200/SF 790 and use a wooden or plastic scraper to remove any residual/cured gasketing material. Remove any burrs that may create shimming between the flanges. It is recommended to use LOCTITE® SF 7063/7064/7070 to degrease and clean surfaces prior to applying the adhesive.
2. Preparation - Activation
If cure speed of LOCTITE® 518 is too slow due to passive metals or low temperature (below 5°C), use activator LOCTITE® SF 7240 or LOCTITE® SF 7649 (see cure speed vs activator graph in the TDS). Allow to dry.
3. Application
Apply a continuous bead of sealant onto one flange surface. Place the bead close to the inner rim of the flange and encircle all bolt holes. Small surface scratches will be filled by the adhesive. LOCTITE® 518 can also be applied by roller onto larger flanges.
4. Assembly
Assemble flanges and tighten bolts as soon as possible. Wipe away any excess squeeze-out, as this will not cure when exposed to air due to sealant's anaerobic curing properties.
5. Disassembly
Disassemble bolts with standard hand tools. Use jacking-screws, cast-on bosses or recesses to lift flanges apart. Once disassembled, apply LOCTITE® SF 7200 or SF 790 on old sealant and use a wood or plastic scraper to remove residues from flange surfaces. For corroded or seized parts, use LOCTITE® LB 8040 Freeze and Release.
Frequently Asked Questions
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LOCTITE® 518
This general purpose, semi-flexible anaerobic-curing gasketing product is ideal for sealing close fitting, rigid machine flanges made of aluminum, iron or steel.