Antifouling & Primer

The boat material and existing old paint are decisive factors. Depending on its condition, GRP often requires a suitable primer (and a barrier coat for osmosis prevention). Steel requires anti-corrosion primers; aluminum requires special, approved systems (incorrect products can lead to corrosion). Wood requires suitable primers and flexible systems depending on its structure. Check the data sheet and approvals—especially for aluminum.

Choose based on water area (freshwater/brackish water/saltwater), time spent at anchor (permanently moored vs. trailer boat), and sailing profile (displacement/planing, speed). In areas with heavy fouling or during long periods of inactivity, a more effective antifouling is advisable; for trailer boats or short seasons, a lighter system may suffice. Important: The antifouling must be compatible with the substrate/primer.

Identify the existing coating (hard vs. self-polishing), check its condition (chalking, cracks, flaking), and then prepare the surface accordingly: thoroughly clean/degrease, sand, and remove dust. If the existing coating is unknown or has poor adhesion, an isolating/adhesive primer is often the safest option. Loose layers must be removed—new antifouling is only as good as the substrate.

Application and film thickness according to the data sheet: the right roller, even distribution, and the recommended recoating intervals are crucial. Recoating too early or too late is a common mistake. Pay attention to minimum temperature, humidity, and drying times. Additional coats are often advisable for edges, the waterline, and heavily stressed areas.

Only if the manufacturer expressly approves it. Without approval, there is a risk of adhesion and compatibility issues (softening, flaking, barrier coats required). If you want to use different systems, a suitable sealer/adhesion primer is often the safe solution.

Common causes of problems include: incorrect substrate (e.g., aluminum without an approved system), failure to degrease, sanding that is too smooth or dusty, incorrect application intervals, conditions that are too cold or damp, or a “mixed application” without primer. If you follow the system properly, the durability will be significantly better.

Store in a cool, dry, frost-free place and keep tightly sealed. Seal containers well (to allow solvents to evaporate), protect from sunlight, and follow the safety data sheet. Stir residues thoroughly before reuse; observe shelf life/pot life (for 2K products).