Yacht Fairing and Surface Preparation

Yacht surface fairing and preparation, with particular emphasis on removing corrosion from steel and aluminium, applying suitable anticorrosive primers and protecting the substrate before finishing.

Surface Fairing and Alignment

We undertake shaping of new structures, fairing of older or uneven surfaces and replacement of damaged or delaminated fairing compounds on hulls and decks. Preparation is specified according to the substrate, its condition and the intended coating system.

Anticorrosive Preparation of Metal Surfaces

Steel and aluminium alloys used in hulls, superstructures and yacht fittings are continually exposed to moisture, salt and temperature changes. On steel, porous corrosion products occupy a greater volume than the original metal, generating stresses that cause coating blistering and delamination. They also retain water and salts, encouraging further corrosion. On aluminium, chloride ions can disrupt the natural protective oxide layer, causing localised corrosion that accelerates inside cavities in the affected surface.

Corrosion Removal and Surface Profile

Before coating, corrosion products, loose coatings and water-soluble contaminants must be removed. Depending on the metal and specification, appropriate abrasive blasting or other mechanical cleaning methods are used. The surface profile must allow complete primer wetting, provide a greater effective bonding area and mechanical anchorage, without excessive peaks that cannot be adequately covered.

On abrasive-blasted steel, the surface profile is measured using replica tape (ISO 8503-5) or assessed with surface-profile comparators (ISO 8503-2). The surface density of water-soluble salts is checked by Bresle extraction (ISO 8502-6) followed by conductivity measurement (ISO 8502-9). Acceptable limits are defined by the coating specification.

Clean steel must be primed within the permitted interval, before surface rust appears (flash rust). Humidity, substrate temperature relative to the dew point and residual salts must be controlled. Aluminium needs preparation methods suited to the specific alloy, without contamination from ferrous abrasives.

Selecting Anticorrosive Primers for Steel and Aluminium

The anticorrosive primer and its pigments must be selected for the specific metal, not simply because the primer is epoxy-based. Depending on the coating system, steel primers may use phosphate-based inhibiting pigments or iron oxides as barrier pigments. A conventional red-oxide primer designed for steel should not be used on aluminium without verified compatibility. Aluminium alloys require suitable surface preparation and primers containing corrosion inhibitors specifically selected for the substrate. An unsuitable primer or contamination with iron-bearing residues can accelerate local corrosion and coating delamination.

On some metal substrates, a dedicated adhesion primer or chemical pretreatment may be applied first (etch primer), but only where specified by the selected system. Appropriate epoxy primer, epoxy fairing compounds and high-build epoxy coatings are then used to shape the surface and create a protective barrier before the finishing coats.

Galvanic Corrosion and Localised Coating Repairs

When dissimilar metals such as steel, aluminium and stainless steel fittings are in electrical contact and simultaneously wetted by seawater, a galvanic couple can form. Electrical isolation, suitable protective coating of interfaces and checks of cathodic protection help reduce galvanic currents and localised corrosion.

If a scratch permits water to penetrate beneath a coating, simply painting over it will not solve the problem. Delaminated coatings and fairing compounds are locally removed until sound substrate is exposed. The repair then involves cleaning, restoring the specified surface profile, applying new anticorrosive primer, compatible epoxy fairing compound and the prescribed protective and finishing coats.

For metal surfaces on yachts, selection of the anticorrosive coating system depends on the substrate metal and its exposure conditions. ISO 12944 distinguishes highly corrosive marine atmospheric exposure (C5 and CX) from immersion in seawater without cathodic protection (Im2) or with cathodic protection (Im4). The primer, anticorrosive pigments and protective coatings must be specifically suited to steel or aluminium and the complete coating system.

Yacht Fairing FAQs

When does a yacht need fairing?

Fairing may be needed when hull or deck surfaces have uneven areas, waviness or damage, or when newly built sections must be blended smoothly into existing surfaces before painting.

What is the difference between fairing and refinishing?

Fairing shapes and levels the surface. Refinishing involves preparation and application of the final paint system. They are often consecutive stages of the same project.

How are fairing materials selected?

Material selection depends on the substrate, project requirements and compatibility with subsequent primers and coatings. The existing surface condition determines the preparation required.