Loctite 518 Gasket Eliminator Flange Sealant 50ml

Loctite 518 is a single-component, medium strength, anaerobic dimethacrylate ester flange sealant. It is a red, thixotropic, gel-like material that forms gaskets in place between close-fitting rigid metal flanges, such as gearbox and engine casings.

It cures on active metals such as mild steel and on passive substrates with low copper content such as aluminium, and tolerates minor surface oils, cleaners with surfactants and corrosion inhibitors. It shows positive fluorescence under UV light for inspection.

Where this product is used

• Gearbox and engine casings
• Close-fitting rigid metal flanges with gaps up to 0.25 mm
• Flanges in active metals such as mild steel
• Flanges in aluminium with low copper content
• Flanges with minor surface oil, cleaner or corrosion inhibitor residue

Features

• Single component, medium strength anaerobic gel
• Thixotropic gel-like material
• Fills gaps up to 0.25 mm
• Uncured, it resists 1.35 MPa at a 0.05 mm gap straight after assembly
• Cures on active metals and on passive substrates with low copper content
• Tolerates minor surface oils, cleaners with surfactants and corrosion inhibitors
• Positive fluorescence under UV light for inspection

Key specifications

Available sizes

Selecting the right option

For a flexible flange sealant that follows minor flange movement see Loctite 515 Master Gasket Flexible Sealant, or for a blue flexible gasket paste see Loctite 5127 Flexible Anaerobic Gasket Eliminator - 50ml (38657). Loctite 510 Gasket Eliminator Flange Sealant is another Loctite flange sealant in the range; check its data sheet for strength and gap fill.

Using it

The Henkel data sheet gives active metals, such as mild steel, and passive substrates with low copper content, such as aluminium, as suitable surfaces. The sealant tolerates minor surface oils, cleaners with surfactants and corrosion inhibitors.

Gap fill is up to 0.25 mm. With a pen roller, the instant sealing limit is a 0.125 mm gap.

An activator can be used as a secondary cure. Cure speed depends on the materials, the gap and the temperature; the cure-speed graphs are in the Henkel data sheet.

Storage and handling

Store unopened in a dry location, optimally between 8 °C and 21 °C. Storage below 8 °C or above 28 °C can adversely affect the properties of the product.

Limits and safety

Not recommended for pure oxygen or oxygen-rich systems, for chlorine or other strong oxidisers, or for plastics, particularly thermoplastics. Check any aqueous wash before use. Strength falls to 15% after 500 hours in unleaded gasoline at 23 °C (5% at 5,000 hours), and Henkel's data show it falling to 50% in 5W30 motor oil and 40% in ATF at 150 °C.

Frequently asked questions

What strength is Loctite 518?

Medium strength. Lap shear on grit-blasted mild steel is 8.4 N/mm² after 24 hours at 23 °C (ISO 4587).

Does Loctite 518 work on aluminium?

Yes, on aluminium with low copper content as well as active metals such as mild steel. Lap shear on aluminium is 5.4 N/mm² after 24 hours at 23 °C.

How soon will Loctite 518 hold pressure?

Uncured, it resists 1.35 MPa at a 0.05 mm gap straight after assembly (0.14 MPa at 0.125 mm, 0.10 MPa at 0.25 mm).

What gap can Loctite 518 fill?

Up to 0.25 mm. With a pen roller, the instant sealing limit is a 0.125 mm gap.

Can Loctite 518 be used with petrol or hot oil?

Not where it will sit in fuel: strength falls to 15% after 500 hours in unleaded gasoline at 23 °C. In 5W30 motor oil and ATF at 150 °C it falls to 50% and 40%.

Does Loctite 518 have approvals?

The current Henkel data sheet lists no approvals; contact AIMS if you need a certificate for a specific application.

Related products

See also: Loctite 515 Master Gasket Flexible Sealant, Loctite 5127 Flexible Anaerobic Gasket Eliminator - 50ml (38657), Loctite 510 Gasket Eliminator Flange Sealant, Loctite 7471 Primer T Surface Preparation Activator Aerosol 133g, Loctite SF 7649 Activator for Anaerobic Adhesives 133ml.