Sea-Line Brush & Roller Thinner for Polyurethane Paints (2K) – 1L

Sea-Line Brush/Roller Thinner for Polyurethane (also known as Brushthinner 2K PU) is specially developed to adjust the viscosity of two-component polyurethane paints and varnishes when they are applied manually – with a brush or paint roller. In hand painting, controlling the paint’s viscosity is critical: if the paint is too thick it can leave brush marks and won’t level well; if it’s too thin, it may run and form a coat that’s too thin. This thinner helps achieve the perfect balance. It ensures the paint is fluid enough to spread and level smoothly, yet viscous enough not to “sag” on vertical surfaces.

By adding Sea-Line Brush/Roll Thinner to the paint (according to instructions, typically 5-20% for brush/roller), you extend the working (open) time of the mixture. This means the paint stays workable longer, which is beneficial when coating larger sections or working in warm conditions – the paint won’t start to gel or dry before you’ve finished brushing out the area. The extended open time allows wet-on-wet application and on-the-fly touch-ups during painting without showing lap marks or variations in gloss.

Using the Sea-Line brush/roller thinner also aids in the paint’s initial set after application, without compromising the full cure. This is important for reducing the wait time between coats and for achieving a hard, durable finish. By using the original thinner, you maintain complete chemical compatibility – the paint+thinner mixture behaves predictably and cures correctly. Generic thinners carry the risk of unwanted side effects or defects (e.g., slower drying, softer film or poor adhesion), so Sea-Line advises using the dedicated thinner for best results.

Applications and usage recommendations:

• Hand Painting Yachts and Boats: This thinner is indispensable when varnishing or painting hulls, decks, wooden rails, and fittings with two-component polyurethane coatings by hand. It helps achieve a professional result even with brush application by minimizing brush marks and contributing to a mirror-like finish.
• Hobbyist & Professional Use: Suitable for DIY boat owners painting small craft or refurbishing wooden elements (e.g., tillers, oars, or marine furniture), as well as professional painters working on larger surfaces. The thinner provides ample time for the paint to flow out, allowing professionals to achieve a spray-like factory finish without actually spraying.
• Compatible Products: Use Sea-Line Brush/Roll Thinner with all Sea-Line two-component polyurethane paints and clear coats – for example, Polyurethane Topcoat (colored paint) or High-Gloss Clear Coat (transparent varnish). For optimal results, follow the recommended dilution percentages given in the technical datasheet of the specific product (typically 5–25% when brushing/rolling, depending on the paint).
• Working Conditions: It is best to apply paint at temperatures between 15°C and 25°C. In higher temperatures, paint can thicken or “flash off” too quickly; adding this thinner slows the drying slightly so you have time to brush it out evenly. In cooler temperatures, properly using the thinner also helps – it improves flow and leveling because very thick paint in cold conditions can leave ridges or drag marks. Adjust the amount of thinner based on ambient conditions (a bit more in heat, a bit less in cold) as needed for ideal performance.