Repairing coloured gelcoat and matching the colour
How to repair a chip in coloured gelcoat and match the colour so the repair is as invisible as possible.
Repairing coloured gelcoat is far harder than white, because the biggest challenge is not the filling technique but hitting the colour. Gelcoat on a hull fades over time under UV, so the original factory shade no longer matches the faded surface around the repair. Colour matching is therefore a process of matching the current state, not a specification from years ago. It is a job that demands patience and an eye — hence the advanced rating.
Start by assessing and preparing the damage. Sand out the chip or scratch, removing loose and cracked material, and gently chamfer the edges so that the new gelcoat keys well. Degrease the surface thoroughly. If the damage reaches the laminate, rebuild the structure first with resin and cloth, with the gelcoat acting as the top layer. A clean, dry, degreased base is the condition for a lasting repair.
Match the colour by trial on samples, not on the hull. Start from the gelcoat closest in colour (white, cream or the builder's base) and correct it with tinters, adding colour drop by drop and noting the proportions. Watch out for two traps: gelcoat looks slightly different once cured than it does wet, and colour must be judged in daylight, ideally right next to the place being repaired. Make a small sample, cure it and only compare it with the hull once it is dry.
The key technical decision is waxed or unwaxed gelcoat and how the top layer is cured. Gelcoat only cures properly with no oxygen present — so either the last coat is made with a wax solution added (surfacing agent), or it is covered with PVC/PET film pressed onto the surface, which excludes oxygen and gives a smooth, fully cured finish. Skipping this step leaves a sticky, under-cured surface that cannot be sanded.
Dose the hardener (MEKP peroxide) strictly as the maker specifies — usually a very small percentage. SAFETY NOTE: MEKP is corrosive and dangerous to the eyes; work in gloves and goggles and keep it away from accelerators (cobalt), because mixing them directly risks a violent reaction. Too little hardener leaves gelcoat that will not set; too much means accelerated fading and cracking. Mix only as much as you will use, because the working time is short.
Application: put the gelcoat on slightly proud of the surface, because the layer shrinks and will be sanded. On small chips, enclosing it completely with film helps. Once cured, wet sand with progressively finer grits (from P400 through P800 to P1500–P2000), levelling the repair with its surroundings. Work carefully at the edges, so as not to sand through the sound gelcoat around the repair.
Finishing means polishing with a cutting compound and then wax or polish, which restore the shine and blend the repair with the rest of the surface. A well-executed repair in coloured gelcoat can be almost invisible, but realistically — on a badly faded hull a perfect match is very hard and sometimes the better answer is to repaint a larger, naturally bounded section. Patience in matching the colour and correct curing of the top layer decide the final result.
Material prices — products and options
Indicative prices in EUR (incl. VAT), as of July 2026. Products widely available in Europe; prices depend on the shop, the pack size and consumption. The links lead to example shops that ship across the EU. Dollar amounts are converted at 1 EUR = 1.1622 USD (ECB, 7 September 2026) and rounded — treat them as a rough guide, not a price in a US shop. Imperial values in brackets are conversions of the metric figure.
Base gelcoat in a colour close to the surface being repaired
- Yachtcare — Gelcoat VT Repairkit
complete kit: 180 g (6 oz) of gelcoat + hardener, film, paper, spatula€32–40 (≈$37–46) - Yachtcare — Gelcoat Crack Repair (RAL)
gelcoat in ready-made RAL shades (9010, 1013, 9001, 5011) for small scratches€9–11 (≈$10–13) - HP-Textiles — topcoat / gelcoat in RAL
gelcoat/topcoat tinted to the RAL palette, for larger areas (approx.)€25–45 (≈$29–52) - R&G — Gelcoat + hardener
clear/coloured gelcoat for tinting with pastes, packs from ~0.5 kg (1.1 lb) (approx.)€20–35 (≈$23–41)
Tinters for correcting the shade
- HP-Textiles — FPN opaque pigment paste
concentrate for gelcoat and resins, many shades, 20–100 g (0.7–3.5 oz, approx.)€5–12 (≈$6–14) - HP-Textiles — set of 7 × 20 g (1 oz) pigment pastes
a set of colours for mixing your own shades (approx.)€18–28 (≈$21–33) - R&G — universal pigment pastes
opaque pastes for polyester and epoxy resins (approx.)€6–15 (≈$7–17)
MEKP hardener and accurate measuring cups
- R&G — MEKP hardener
peroxide for gelcoats and polyester resins, 30–100 g (4 oz) bottle (approx.)€6–14 (≈$7–16) - Yachtcare — VT Gelcoat Filler (with hardener)
filler/gelcoat with a separate hardener included€20–22 (≈$23–26) - HP-Textiles — measuring cups and stirrers
graduated cups and sticks for accurate dosing (approx.)€3–8 (≈$3–9)
A wax solution (surfacing agent) or PVC/PET film to exclude oxygen
- R&G — wax additive (surfacing agent) for gelcoat
paraffin dissolved in styrene, allows the surface to cure (approx.)€8–16 (≈$9–19) - Yachtcare — Hostaphan film (in the Repairkit)
PET film that keeps oxygen out during curing (part of the kit)€32–40 (≈$37–46) - HP-Textiles — PVA/PET release film
sheet or roll of film to cover fresh gelcoat (approx.)€4–12 (≈$5–14)
Wet-and-dry paper in grits from P400 to P2000
- CROP — wet-and-dry paper set P320–P800
grits for the initial levelling of the repair (approx.)€6–10 (≈$7–12) - CROP — wet-and-dry paper set P1000–P3000
finishing grits before polishing (approx.)€7–12 (≈$8–14) - 3M — Wet or Dry P2000 (sheets)
professional wet-and-dry paper, multi-pack (approx.)€15–30 (≈$17–35)
Cutting compound and wax/polish
- Farécla — G3 rubbing compound
removes P1500 and finer marks, by hand or machine, 400 g (14 oz)–1 kg (2.2 lb)€13–20 (≈$15–23) - 3M — Perfect-It polishing compound
cutting and finishing system for gelcoat and paint (approx.)€20–35 (≈$23–41) - Protective wax/polish for gelcoat
protective layer that preserves gloss after polishing (approx.)€12–25 (≈$14–29)
Degreaser, sanding tools and spatulas
- R&G — degreaser / cleaner for laminate
surface preparation before applying gelcoat (approx.)€6–14 (≈$7–16) - Spreaders and sanding blocks
plastic spreaders and blocks for wet-and-dry paper (approx.)€4–15 (≈$5–17) - HP-Textiles — laminating accessories
brushes, rollers, disposable spreaders (approx.)€3–10 (≈$3–12)
Nitrile gloves and safety glasses
- CROP — nitrile gloves (100 pcs)
resistant to styrene and solvents, pack of 100€13–16 (≈$15–19) - Safety goggles
eye protection when sanding and working with gelcoat (approx.)€3–10 (≈$3–12)
Price sources: SVB24 (Yachtcare), HP-Textiles, R&G Faserverbundwerkstoffe, Farécla (G3), CROP / nonpaints.com, Compass24