Sea-Line Universal Yacht Primer 1K – Universal One-Component Boat Primer

Sea-Line Universal Yacht Primer 1K is a versatile single-component primer that stands out for its ease of use and broad range of applications in the marine field. Its chlorinated rubber base gives it excellent flexibility and adhesion to various substrates, making it suitable for fiberglass (polyester/epoxy composites) as well as wood and steel. This primer acts as an intermediary layer that improves the bond between different types of paints and coatings, especially when transitioning from one system to another (for example, from an epoxy primer to a one-component topcoat, or when painting new layers over old paint). Sea-Line 1K Primer dries quickly and requires no complex mixing or special skills – it is ideal for boat owners who want to do their own paint touch-ups or maintenance.

• Functions & Uses: As a multipurpose primer, it has several key applications:
  – Primer coat: Applied on bare or cleaned surfaces of fiberglass, steel, or wood, it provides an initial protective and adhesive layer. On steel it offers basic corrosion protection (chlorinated rubber primers have traditionally been used as anti-rust primers), though for long-term underwater metal protection an epoxy system is recommended. On wood it seals the pores and isolates natural oils (except teak – high oil content teak requires special treatment) before painting or varnishing. On GRP/gelcoat it lays down a thin “bite” layer that helps subsequent paints adhere well and spread evenly without peeling.
  – Tie-coat/Intermediate layer: Universal Primer 1K is excellent for repainting projects – when you’re going over an old paint (e.g. unknown or 1K paint) with a new system, this primer acts as a sandwich layer. It sticks to the old surface and provides a fresh keyed surface to which the new paint will adhere strongly. This helps avoid potential incompatibility or poor adhesion between the old and new coatings.
  – Barrier over antifouling: It can be used to isolate an old antifouling paint before applying a new one (especially if the old coating is of unknown type or already inactive). One or two coats of the 1K primer will seal in the remnants of old antifouling and provide a smooth, inert surface for the new antifouling to grip – this prevents any adverse reaction between different antifouling brands and improves durability.
• Characteristics: The primer is grey in color (matte), which provides a neutral base for almost any topcoat color. It applies easily by brush or roller; thin it with the dedicated Thinner for 1K Primer/Varnish/Enamel (up to ~10% for brush/roller, ~20% for spraying) to achieve the desired consistency. It dries to touch in about 1 hour (at 20°C) and can be recoated after roughly 5 hours. It’s rain-resistant in ~4 hours and fully waterproof (cured) after ~16 hours. For launching, allow at least 24 hours drying. At a dry film thickness of ~65 μm per coat, two coats are typical for good coverage. The primer does impart some anti-corrosive properties, but as a single-component product, its primary role is adhesion rather than heavy-duty corrosion blocking – for submerged metal parts it is best used over an epoxy system.
• Compatibility: Sea-Line Universal Primer 1K is compatible with all Sea-Line one-component paints and varnishes (e.g., the one-part yacht enamel, one-part marine varnish, etc.). It can be overcoated with two-component paints as well, BUT generally applying 2K paint over a 1K primer in high-stress or immersion areas isn’t recommended, as the softer 1K layer could undermine the harder 2K finish – therefore use 1K primer mainly under 1K finishes or as a temporary barrier. This primer can be directly overcoated with antifouling paint, since chlorinated rubber coatings historically make good bases for antifouling. The primer does not require sanding between coats or before painting, provided you stay within the recoat intervals – the surface remains slightly textured and matte to ensure good intercoat adhesion. If more than a few days (usually 7+ days) have passed since application, a light scuff with fine sandpaper (P320-P400) will refresh the surface for painting.
• Available Packaging: It comes in 0.75 L and 2.5 L cans to cover both small and larger projects. This primer is the perfect choice for those looking for an easy “one-can” solution (no hardener mixing) to prime their boat and enhance the longevity of their paint system.