Preparation
Typical problems are dust, dirt, grease, oil, rust, flaking paint etc. The preparation selected will depend on the type of substrate (metal, plastic, wood, etc), the operating conditions in service, the degree of surface deterioration and the practicalities of any particular installation. Note that cured polyurethane sealants cannot be removed with chemical cleaners, only by mechanical techniques such as cutting, scraping or grinding.

Mechanical Cleaning
Mechanical preparation will be required if, for example, corrosion is apparent, weak surface layers prevail, or surface degradation is showing. The level of cleaning will be determined by the type of surface and the degree of deterioration.

Preparation techniques include the use of abrasive nylon pads, abrasive paper/fabric, wire brushing, abrasive wheels, wet or dry grit blasting or steam cleaning/jet washing. Following mechanical treatment, additional cleaning with solvents may also be required.

De-dusting, Degreasing
If compressed air is used to remove dust from surfaces, the air should be filtered to remove traces of oil. The use of vacuum cleaners is even better for dust removal. All non-porous surfaces must be cleaned prior to Sikaflex® application.

Only Sika recommended cleaning materials should be used. Solvents such as white spirit and alcohol based are not recommended as they can hinder cure or affect subsequent adhesion.
Always use clean, lint-free (preferably disposable) wipes and change them frequently to ensure that the contamination is removed from and not redistributed onto the surface.

Once clean, the substrates should be left to dry completely before proceeding to the next operation.
Note: Certain alcohol based solvents, including Sika® Aktivator 205, are not recommended for use on absorbent substrates as trapped solvent in the surface will inhibit the cure of Sikaflex®

Priming
Priming is a means of transforming a surface, either chemically, physically or both, into an ideal condition for successful bonding, thus ensuring long term performance. The simplest form of priming is wiping the prepared surface with a conditioner (such as Sika® Aktivator) which reacts with the surface providing improved “wetting” characteristics and more reactive sites.

Porous and rough surfaces require a primer with “film forming” properties to re-profile the surface, producing a denser, more even bond line.

Primers must always be allowed to dry thoroughly before application of the Sikaflex® adhesive. If left too long, primed areas must be reactivated.

Primed surfaces should be protected from contamination by dust, dirt, grease, vapours, moisture etc, until the bond is formed.

KEY:
Ab – Abrasive nylon pad
Gr – 80 grit paper
205 – Sika Aktivator 205
SA – Sika Aktivator
209N – Sika Primer 209N
SMM – Sika MultiPrimer Marine

NOTE: For Sikaflex 290iDC use on teak, as per recommendation in table.

Notes on Sika Priming & Surface Preparation Products

Sika Aktivator 205
Sika® Aktivator 205 is an alcohol solution containing a bond activating substance designed for the activation of surfaces prior to bonding and sealing with Sikaflex products.
Sika Aktivator 205 is used to activate the following non-porous substrates: metals, plastics, glazed ceramics, painted surfaces.

Sika Aktivator
Sika® Aktivator is an activating agent used to improve adhesion. It is specifically formulated for the treatment of bond faces prior to application of various Sika® polyurethane adhesives.

Sika® Aktivator improves adhesion on substrates such as glass, ceramic coated glass, the cut face of old polyurethane adhesive, polyurethane pre-applied windows and two pack paint systems.

Sika Primer 209N
Sika®Primer 209N is a black pigmented liquid of low viscosity which dries by reaction with atmospheric moisture. It is used to prime painted surfaces and plastic substrates prior to bonding with Sikaflex® products.

Sika® Primer 209 N is suitable for application to the following substrates: Plastics: Acrylic (PMMA) Polycarbonate (PC) ABS, etc. Because plastics vary so much in their chemical composition, preliminary trials are necessary. Always seek manufacturer’s advice before using primer on plastics that are prone to stress cracking, such as acrylics, polycarbonates or ABS.

Sika Remover 208
Sika® Remover 208 is used to remove traces of uncured Sikaflex® products as well as for cleaning painted substrates.
Sika® Remover 208 can be used to remove uncured excess material of Sikaflex® adhesive or sealant from application tools or from soiled surfaces.
Sika® Remover 208 can also be used for the pre-cleaning of strongly contaminated non-porous substrates.