Loctite surface sealants from Henkel

With its Loctite surface sealants, the adhesive manufacturer Henkel provides an excellent alternative to conventional solid sealants.

In the following article, you will find out what surface sealants are, their advantages, selection criteria and the purchase options in the online store of the Swiss Henkel distributor abovo. We also provide information on the application of Loctite surface sealants.

What are surface seals?

A surface seal is a liquid sealant that is applied to a surface in the form of a viscous mass – similar to an adhesive – in order to connect this surface to another. As a rule, these surfaces are so-called flanges. By joining these flanges tightly together with the help of the surface seal, two components are usually connected to each other in such a way that no media can escape from inside or outside, in particular no liquid or gaseous media.

Liquid gaskets differ from conventional flange gaskets in that the latter use solid materials – such as paper, cardboard, metal, rubber or plastic – to ensure tightness, which is why they are also known as solid gaskets. As they do not adhere to the flange surface but achieve the seal by compression, i.e. by pressing the two flanges together using screws or clamps, they are also known as compression gaskets. A distinction is made between flexible solid gaskets – such as those based on silicone – and non-flexible solid gaskets – such as those based on paper.

While liquid gaskets are virtually self-forming, solid gaskets have to be produced precisely for the respective application, e.g. punched out in the case of paper-based gaskets.

The areas of application for surface sealants include

Flanges, e.g. on pipes
Pump housing
Plastic housing
Motors
Gearbox
Oil pans

Under the following link you will find an interesting webinar from Henkel-Loctite with explanations on the subject of surface sealants and a demonstration of various Loctite surface sealants on a flange: “LOCTITE Webinar Surface Sealants“

Advantages of gaskets over solid gaskets

Liquid gaskets have a number of advantages over conventional solid gaskets. However, we will first look at the disadvantages of solid gaskets, which include the following disadvantages:

Setting after a certain operating time makes readjustments necessary
Each solid gasket must be punched out or molded to fit the respective geometry, which requires a high stock level
Corrosion/ mating surface corrosion
Susceptibility to leaks due to: basically no 100% surface contact, irregular surfaces, setting behavior makes gaskets thinner, migration (pressing out of the gasket), flange deformation due to high clamping forces, flange bending due to different materials, damage in the area of the threaded hole due to breaking, tearing, tearing in, pressing out

The advantages of liquid surface sealants include the following:

Due to viscosity, sealant can penetrate even the finest surface irregularities
No readjustment necessary as zero gap
longer service life of the end products
Greater reliability and therefore fewer failures
High-performance sealing possible; resistant to high pressures after curing
Lower storage costs, as one product can be used for many different flange geometries
Good to excellent chemical resistance (depending on the surface sealing product)
High heat resistance
Easy disassembly with appropriate cleaning agent

Selecting the right surface seal

The following criteria are decisive when deciding which surface seal to choose:

Size of the sealing gap
Material of the parts to be sealed (metal, plastic or combination)
Flange type (torsion-resistant or flexible)
Curing system (anaerobic or humidity)
Oil resistance
Water/glycol resistance
Operating temperature range
Container size
Dosing devices

Buy Loctite surface sealant from abovo

In the online store of the Swiss Henkel–distributors abovo you can various Loctite surface sealants from Henkel whose properties are presented in the following table:

	Loctite 518	Loctite 5188	Loctite 510	Loctite 5205	Loctite 573	Loctite SI 5910
max. gap	0.25 mm	0.25 mm	0.25 mm	0.25 mm	0.1 mm	1 mm
Flange material	Metal	Metal	Metal	Metal	Metal	Metal or plastic
Flange type	Torsion-resistant	Torsion-resistant	Torsion-resistant	Torsion-resistant	Torsion-resistant	Flexible
Curing system	anaerobic	anaerobic	anaerobic	anaerobic	anaerobic	Air humidity
Application temperature range	-55 to +150 °C	-55 to +150 °C	-55 to +200 °C	-55 to +150 °C	-55 to +150 °C	-55 to +200 °C
Container size	25 ml syringe; 50 ml, 300 ml cartridge	50 ml, 300 ml, 2 l	50 ml, 250 ml, 300 ml cartridge	50 ml, 300 ml	50 ml, 250 ml	50 ml, 300 ml cartridge; 80 ml tube; 200 ml pressure can
abovo online store	Order	Order	Order	Order	Order	Order

Application notes for surface sealants

For the use of Loctite surface sealants, the manufacturer Henkel gives in its pocket book Loctite Repair Expert the following application instructions:

1. preparation

The first preparatory step is to clean the surface to which the surface sealant is to be applied.

To remove old seals, use the Loctite SF 7200 adhesive and sealant remover is recommended. is recommended. After applying this component cleaner to the old seal, the seal residue should be removed using a wooden or plastic scraper. The surface should be deburred.

You may also be interested in the following article: “Component cleaner: LOCTITE SF 7200 adhesive and sealant remover“

Before applying the new surface sealant, the surface should be cleaned with the help of surface cleaner Loctite SF 7063 degrease and clean the surface.

On the other hand, an activator should be used in this initial preparation phase if the curing speed of the Loctite 518 and Loctite 510 surface sealants is too slow due to passive metals or low temperatures of below 5 °C. An activator is not required for the surface sealants Loctite SI 5980 and Loctite SI 5990.

2nd application

For small and medium-sized flanges, the surface sealant should be applied to one side of the flange with a continuous, closed bead. Make sure that the bead is applied close to the inner edge of the flange. The bead should circle around holes. If there are small scratches, these can be filled with the surface sealant.

For large flanges, a roller can also be used for applying Loctite 510 and Loctite 518 surface sealants.

3. assembly

In a third step, the flange surfaces can now be mounted, whereby the screws should be tightened as soon as possible.

4. disassembly

If you want to dismantle the flanges connected with the surface seal, you can first remove the screws with normal hand tools. The flange can then be lifted off with the help of jacking screws, cast-on tabs or recesses. If parts are corroded or seized, Henkel recommends the use of Loctite LB 8040 Freeze & Release.

You may also be interested in the following article: “Loctite overview for download: Loctite repair expert pocket book“

Advice on Loctite surface sealants from Henkel

We at abovo will be happy to help you select the right Loctite surface sealant for your application.

Abovo has been an authorized distributor of Henkel Adhesive Technologies products for over 15 years; initially in the Henkel Electronics division and since 2022 also in the Henkel Industry division.

The best way to contact the Loctite surface sealing experts at abovo is by telephone or e-mail: