It depends.

Recommendation: Complete Removal

We generally recommend complete removal of old antifouling layers. This creates the best substrate for a durable F2 coating and ensures long-lasting adhesion.

Alternative: Surface Preparation

However, if you do not completely remove old layers, this is acceptable as long as the existing surface is smooth and stable. Products where this is possible (as long as the surface is undamaged) include: VC 17m, VC Offshore, Hempel Mille NCT, Seajet 037 Coastal, and International Ultra 300.

• Sanding: Sand the surface evenly with K120–220 grit sandpaper until it is smooth and stable.
• Cleaning: Then thoroughly clean the surface with F2 EcoDegreaser to remove all residues and sanding dust.
• Sealing: Use F2 Primer as a sealing and adhesive substrate.

Important Note: Moisture

Moisture in the hull – for example due to osmotic problems, trapped moisture in old coatings, or condensation – must be completely removed before applying F2. Trapped moisture can cause blistering or partial peeling of the coating as the moisture attempts to expand or escape.

Important Note: Silicone Antifoulings

F2 is not compatible with silicone antifoulings. Silicone antifoulings must always be completely removed as F2 does not adhere to these surfaces.

Yes, F2 is suitable for application on aluminum hulls.

The coating does not contain metallic components that could react with aluminum. Additionally, F2 provides waterproof protection that protects aluminum and reduces the risk of corrosion.

Nevertheless, we recommend applying a special anti-corrosion primer under the coating.

Yes, F2 EcoHull provides protection against osmotic processes.

The F2 coating is designed to be waterproof. It creates a barrier that effectively prevents water penetration into the hull. This significantly contributes to protection against osmosis, which occurs due to moisture in the laminate.

Recommendation for Additional Protection

Although F2 already provides protection, for maximum safety we always recommend using a classic two-component epoxy primer as a base coating. This primer provides a completely dense and robust barrier against osmosis.

Primer Selection

When selecting a two-component epoxy primer, it is important to consider the following:

• Ideally, use a solvent-free primer. Such primers can be directly overcoated with F2 Adhesive Coat when they are ready for the next layer application.
• If your primer contains solvents, it must be aired for several days before applying F2 Adhesive Coat. For optimal adhesion, it is advisable to lightly sand the surface after airing.

Yes, this is possible. F2 can be easily applied directly over existing two-component primer (2K primer). In this case, additional F2 Primer is not required.

Surface Preparation:

• Check primer type: If it is a solvent-free primer, you can skip airing and re-sanding.
• For solvent-containing primer: If the primer contains solvents, it must be aired for several days after application until the solvents completely evaporate.
• Re-sanding: For optimal adhesion, we recommend lightly sanding the surface after airing.
• Thorough cleaning: Ensure the surface is dust-free before beginning F2 application.