Gelcoat colours for glass-reinforced plastic boats

Glass-reinforced plastic boat colours

The top layer of glass-reinforced plastic structures on boats is gelcoat, which is a polyester-based gel-like coating. During the manufacturing process, gelcoat is sprayed or brushed into the mould before the actual structure is laminated. The thickness of the gelcoat surface is typically 0.4-0.8 mm.

White gelcoat is most commonly used on boats, but the gelcoat can also be coloured using pigment-containing pastes.

Colour resistance and discolouration of gelcoats

The colour resistance of gelcoat surfaces is affected mostly by UV radiation from the sun. UV radiation is always high on the sea and lakes, so it will inevitably affect the surface colour and gloss of all boats over time. Small differences in colour are further accentuated, for example, when the canopy protects only part of the boat from the sun.

In addition to UV radiation, boat colours are affected by local air pollutants (from traffic, industrial emissions and soot) and the mechanical wear of surfaces by fenders and along access routes.

The discolouration of surfaces is purely cosmetic and does not affect the structural durability or performance of the boat. Discolouration caused by UV radiation in particular must be taken into account if the surface of the boat needs to be repaired, in which case the colour of the patch material must be adapted to the actual surface colour of the boat.

Maintenance and care instructions for gelcoat surfaces

In order to minimise discolouration and maintain gloss, the most important steps are regular washing and waxing. To repair worn or faded surfaces, the first step is to carefully wash the boat and then apply cleaning waxes, after which the boat should be waxed again using a quality boat wax.

If these cleaning products are not effective enough, lightly abrasive methods may be used. When treating glass-reinforced plastic surfaces with boat care products, always follow the instructions provided by the manufacturer.

During the production process, the quality of glass-reinforced plastic is kept as uniform as possible through careful working methods, extremely accurate dosing of hardener and dyes, and always keeping the raw materials at a constant temperature. The primary selection criteria are their long-term qualities, such as weather, chemical and colour resistance.

Maintenance and care instructions for glass-reinforced plastic boats

  • Keep your boat clean and wax it thoroughly with a quality boat wax at least once a year.
  • Wash your boat before winter storage and protect it from the weather and dirt outside the boating season.
  • Avoid washing the boat with strong acidic and corrosive substances and solvents to avoid damaging the gelcoat surface. Products containing chlorine in particular can damage the surfaces of glass-reinforced plastic boats.
  • Use mechanical polishing only at low speeds to prevent the gelcoat surface from overheating. Vigorous grinding and heated surfaces can cause permanent damage to the surface layers of the glass-reinforced plastic. Carefully follow the instructions provided by the manufacturers of the materials and tools being used and, if necessary, consult a professional.
  • Do not use abrasives or waxes that contain silicone. If silicone penetrates into the pores of the material, it can cause adhesion problems if the glass-reinforced plastic structure needs to be repaired at some point.

Detailed instructions are available from boat care product manufacturers: 

Discolouration of gelcoat surfaces and warranty issues

Minor changes to the boat’s outer surfaces caused by weather and UV radiation and that do not affect the structural durability or performance of the boat are not considered defects covered by the warranty. Similarly, changes due to normal wear and tear, such as a loss of gloss, are not considered defects.

Although small changes in colour are not considered defects, all issues reported by customers are investigated separately. All warranty issues are handled by our dealers.