Can you overcoat antifouling?

Existing antifouling can often be overcoated if it adheres firmly, is clean and is compatible with the new product. Cracks, blisters, flaking or an unknown system require closer inspection.

When is direct overcoating possible?

A direct maintenance coat is possible when the existing coating is closed and sound and the combination is approved in the compatibility table. Clean and prepare the surface exactly as specified in the new product's data sheet. A small test patch can provide an indication but does not replace the manufacturer's compatibility information.

When is a barrier or adhesion coat needed?

On a sound but unknown or not directly compatible existing coating, Seajet 015 Underwater Primer can be used as an adhesion or barrier coat. The required coat number and overcoating interval depend on the substrate and data sheet. Primer cannot stabilise loose or poorly adhering layers.

When must the existing coating be removed?

• The coating flakes, cracks or fails an adhesion check.
• Many thick and uneven old layers have built up.
• Blisters, corrosion or damage to gelcoat, laminate, wood or metal are visible.
• The new system requires a complete rebuild from the substrate.

Use a removal method suitable for both substrate and coating. Collect sanding dust, stripper and paint residues and dispose of them according to local rules.

Preparation in the right order

1. Remove fouling and dirt at a designated wash area.
2. Check the type and adhesion of the existing coating.
3. Remove loose areas and feather sound edges.
4. Clean, sand and dry as specified in the data sheet.
5. Apply primer or barrier coat if required.
6. Apply antifouling in the specified number of coats.

Temperature, humidity, dew point and overcoating and launch times are product-specific. Wear the personal protective equipment listed in the safety data sheet. The configurator considers the existing coating when selecting the system.